Vegetable production is essential for food and nutritional security but faces significant challenges associated with conventional agricultural practices, particularly the excessive use of chemical fertilizers. Although these inputs ensure high productivity, they have contributed to soil degradation, water pollution, greenhouse gas emissions, and nutritional erosion of food. These factors compromise crop quality, food quality, and the sustainability of agricultural systems. In this context, the use of biofertilizers and rock powders emerges as a sustainable alternative, promoting soil health, increasing nutrient availability, and enhancing crop resilience, while also contributing to waste recycling and sustainable resource management. Thus, the study aimed to evaluate and recommend sustainable agricultural practices focused on the use of biofertilizers and rock powders (mining co-products) in the organic production of vegetables in Chã Grande, Pernambuco, Brazil. The experiment was conducted on three properties managed by female farmers, using a randomized block design with a 3x3 factorial arrangement. An organic compost, a digestate from biogas production, and two types of mining co-products, characterized as amphibole and basalt, were tested. Under this context, four successive planting cycles were carried out, with the cultivation of American lettuce (Lactuca sativa L.), arugula (Eruca sativa L.), and coriander (Coriandrum sativum). Throughout the cycles, productivity, nutrient extraction by the crops, and soil attributes were estimated. The results indicated that organic inputs applied in isolation promoted the greatest short-term increases in productivity. In contrast, mining co-products, whether applied alone or in association with organic inputs, were strongly associated with increased soil respiratory activity and microbial growth, as well as with the reorganization of carbon among the different soil fractions. Furthermore, organo-mineral interactions promoted higher macronutrient contents in plant tissue and contributed to the formation of a more complex and functional soil–plant system. By promoting the use of sustainable inputs, this research aligns with the United Nations Sustainable Development Goals (SDGs), fostering food security, environmental conservation, and economic resilience.

To meet global food demand and overcome the problem of phosphorus (P) fixation in soils, producers use excessive amounts of phosphate fertilizers. This generates great concern, as the overuse of these inputs can impact natural resources, such as the depletion of phosphate rocks. Viticulture plays an important role in the Brazilian economy, and the São Francisco Valley, located in the states of Bahia and Pernambuco, stands out in the production and export of the fruit and its derivatives. Thus, to maintain vineyard productivity, high doses of phosphate fertilizer are applied, which can result in environmental problems. In this context, Phosphorus-Solubilizing Bacteria (PSB) emerge as a viable and sustainable alternative to make the nutrient available in the soil and meet part of the plants' demand. However, the literature presents few studies focusing on soil health after PSB inoculation in the field, especially in table grape cultivation. Thus, this research aimed to evaluate soil health using chemical, biological, and enzymatic indicators after inoculation with BSP, isolated from soils of the Brazilian semi-arid region, in grape cultivation in the São Francisco Valley. The experiment was conducted on a commercial farm producing premium table grapes. The vines were inoculated with BSP first after drastic pruning, and a second inoculation was performed during the berry filling period. The factorial arrangement was 7 x 2 + 2, composed of seven types of BSP (PL1A, PL1B, LU10E, PL18E, PL1A+PL18E, PL1B+LU10E and the commercial product BiomaPhos®), two phosphorus doses (0% and 50% P), and two controls: an absolute control (without inoculation and fertilization) and a fertilized control (without inoculation and with 100% of the recommended dose). The experimental design was a randomized complete block design (RCBD) with four replications. At the end of the experiment, soil samples were collected at depths of 0-20 and 20-40 cm. Chemical (pH, available P, exchangeable K+, total N, and TOC), microbiological (RBS, CBM, PBM, qCO2, and qMIC), and enzymatic (alkaline phosphatase, beta-glucosidase, arylsulfatase, and urease) attributes were analyzed. The results showed that inoculations with BSP promoted increases in several attributes related to soil health. Available phosphorus in the fertilized control treatment showed a content of 213.31 mg kg⁻¹, while BSP LU10E showed 427 mg kg⁻¹ of available P with a 0% P dose; with a 50% P dose, 444.18 mg kg⁻¹ was obtained. Therefore, there were increases of 100.50% and 108.23%, respectively, with the inoculation of this bacterium. BSP PL18E, with 50% of the P dose, provided a CBM of 101.90 mg kg⁻¹ in the subsurface (20-40 cm), while the value of this same variable with the application of 100% of the recommended P dose was 31.50 mg kg⁻¹, representing an increase of 223.49%. Alkaline phosphatase enzyme activity was significantly improved with inoculations, mainly with the PL1B+LU10E consortium (50% P), which showed a value of 2907.66 μg p-nitrophenol g⁻¹ h⁻¹, while the 100% control showed 1122.83 μg p-nitrophenol g⁻¹ h⁻¹, an increase of 158.96%. It is concluded that the use of native BSP from the Brazilian semi-arid region is efficient in making phosphorus available and promotes improvements in soil health, in addition to enabling a 50% reduction in mineral phosphate fertilization in table grape cultivation in the São Francisco Valley.

Tropical soils represent one of the most complex and dynamic ecosystems on the planet, due to their formation under conditions of extreme weathering and pedogenic processes such as rubification and xanthization, which result in physical and chemical characteristics that impact agricultural management practices. Therefore, the overall objective of this study is to investigate the genesis of the rubric character in soils of the 'Sea of Hills' (Mar de Morros) environment in the Zona da Mata of Pernambuco, aiming to understand its relationship with mineralogy, climate change, soil fertility, and its taxonomic significance. The study area comprises Latosols (Oxisols) located in the Zona da Mata region of Pernambuco. Chemical and physical soil parameters were evaluated, along with mineralogical composition via X-ray diffraction (XRD), selective iron extraction, total chemical composition by X-ray fluorescence (XRF), micronutrients, lithological discontinuity, micromorphology, and statistical analyses. The four soil profiles exhibited strong morphological and pedogenic similarity, featuring deep profiles with colors ranging from yellowish to reddish. Chemically, the soils showed strong acidity, low exchangeable base content, and high potential acidity and exchangeable Al3+. The Cation Exchange Capacity (CEC) was low, consistent with highly weathered soils dominated by kaolinite and Fe/Al oxides, with low phosphorus availability and high fixation controlled by the soils' oxidic mineralogy. Organic carbon contents were higher at the surface, gradually decreasing with depth. Selective extraction of iron and aluminum revealed a higher concentration of crystalline oxides in the red horizons and a higher content of low-crystallinity oxides at the surface, influenced by organic matter. Micronutrients were influenced by chemical characteristics primarily related to soil fertility. Mineralogical attributes confirmed the relationship between iron oxides and physical, chemical, and morphological features. Micromorphology revealed pedofeatures indicating that Fe mobility is mainly governed by pore hydrology and preferential flow. Multivariate analysis confirmed the separation of soil attributes related to the red and yellow horizons. The soils studied in the Mar de Morros environment of the Pernambuco Zona da Mata were classified as Latossolos Amarelos Distróficos (Dystric Yellow Latosols) according to the SiBCS, with distinctions at the fourth categorical level related to the presence of the rubric character, and as Ferralsols according to the WRB system. The profiles feature a thick latosolic (oxico) B horizon, low clay activity, a reduced silt/clay ratio, and a predominance of kaolinite and crystalline iron oxides, confirming an advanced weathering stage and intense desilication. It was observed that the rubric character, as defined by the SiBCS, applies to soils showing subsoil reddening, characterized by a moist color with a hue redder than 5YR and a value $\le 4$. However, the current definition of this character presents operational limitations, especially regarding the 'value' criterion, necessitating a revision of the rubric character’s wording to ensure greater coherence between taxonomic classification and the chromatic variability observed in highly weathered soils. Overall, chemical, physical, mineralogical, and micromorphological evidence indicates that the rubric character results from the interaction between parent material, weathering intensity, desilication, and the dynamics of iron forms.

In the Northeast of Brazil, the coastal plateaus stand out as an important agricultural hub, especially in the cultivation of sugarcane. In this geological formation, crops are established on predominantly sandy and dystrophic soils, which may have hardened horizons at different depths. These horizons influence water percolation, favoring periods of saturation and altering the soil's redox conditions, which directly affects the availability of nutrients such as iron (Fe) and manganese (Mn). During dry periods, crops grown in this region are more susceptible to deficiencies of these micronutrients due to their lower mobility and availability in the soil. Conversely, during the rainy season, the presence of hardened and dark horizons (Bh) can promote temporary soil saturation and increase the availability of Fe and Mn, especially under reducing conditions. Sugarcane grown in this edaphic environment often exhibits symptoms such as leaf chlorosis characteristic of iron deficiency and longitudinal streaks associated with manganese deficiency, the manifestations of which may vary throughout the growth cycle. In this context, the objective of this research is to evaluate doses of Fe and Mn in different redox environments, influenced by the rainfall water regime, and their effects on the nutrition, photosynthetic pigments, biochemistry, and productivity of sugarcane grown in the sandy soils of the coastal plateaus of the Northeast. The experiment was conducted on sandy soil classified as Hydromorphic Spodosol, in a commercial area belonging to Usina Japungu, located in the municipality of Santa Rita–PB, cultivated with sugarcane, in the fourth ratoon cycle of the RB92579 variety. The treatments were arranged in a randomized block design, with three blocks, using a factorial scheme (6 x 2) + 1. There were 6 doses of Fe (1.5; 3.0; 6.0; 9.0; 12.0; and 15.0 kg ha-1), using FeSO4 as the source, 2 doses of Mn (1.5 and 3.0 kg ha-1), using MnCO3 as the source, plus a control treatment that did not receive any micronutrient application. Evaluations were carried out at three points corresponding to rainfall variation in the region, identified as the rainy period (May/June/25), the beginning of the dry season (August/September/25), and the peak of the dry season (November/December/25). In the plants, chlorophyll fluorescence and photosynthetic pigments were analyzed to assess photosynthetic efficiency, as well as electrolyte leakage to evaluate the plant's antioxidant response. At the end of the cycle, the plant's response to the treatments was evaluated through growth biometrics and quantification of agro-industrial productivity. In all three evaluation periods, the addition of Fe and Mn promoted an increase in the production of photosynthetic pigments. Chlorophyll fluorescence, in turn, was negatively affected during the period of highest rainfall, with the highest doses showing a possible toxic effect of these micronutrients. Plants subjected to the lowest doses of Fe and Mn showed a reduction in electrolyte leakage, indicating less damage to cell membranes. Despite the beneficial effects observed on photosynthetic efficiency and the mitigation of oxidative stress, the vegetative growth and productivity of sugarcane were not significantly influenced by the application of Fe and Mn to the soil. However, 1:1 or 2:1 type relationships proved to be more promising, as they provided improvements in the plant's photosynthetic and antioxidant dynamics with lower input requirements, without compromising productivity.

The Brazilian semi-arid region is characterized by soils with distinctive properties re sulting from the interaction between climate (low annual rainfall <600 mm yr⁻¹ and high evapotranspiration) and diverse parent materials. In this context, the alluvial soils of the Mox otó River floodplain, within the Jatobá Basin (Ibimirim, Pernambuco), represent systems with high productive potential for irrigated agriculture; however, they present limitations related to salinity and uncertainties regarding the dynamics of essential nutrients such as potassium (K). This thesis aimed to investigate: (1) the origins of salinization and its pedogenetic effects, and (2) the mechanisms of potassium fixation and release as a function of the mineralogy of dif ferent particle-size fractions. Two representative alluvial soil profiles were sampled and sub jected to chemical analyses (ionic composition, electrical conductivity, total elemental con tents by X-ray fluorescence, exchangeable and soluble potassium, cation exchange capacity, and selective Fe extractions), mineralogical analyses (X-ray diffraction, mineral saturation in dices, scanning electron microscopy coupled with energy-dispersive spectroscopy, and mi cromorphology), and K fixation experiments in the air-dried fine earth, fine sand, silt, coarse clay, and fine clay fractions. The results presented in the first chapter demonstrated that sali nization is predominantly controlled by geochemical and hydrogeological factors rather than by irrigation practices. Surface horizons exhibited extreme salinity with ionic signatures dom inated by Na–Cl and Ca–SO₄, whereas irrigation waters showed substantially lower electrical conductivity and distinct chemical composition. Geochemical modeling and stratigraphic evi dence indicated the dissolution of underlying evaporitic/lacustrine deposits and upward transport via water table fluctuation as the primary mechanism of salt input. Pedogenetic re sponses included pronounced gypsification (gypsum precipitation in biopores, surface crusts, and subsurface horizons, with saturation indices >1), incipient calcification at depth, and in termittent gleying associated with temporary reducing conditions. The second chapter re vealed that the soils exhibit total K₂O contents (3.9–4.1%) substantially higher than those typ ically reported for highly weathered tropical soils (1–2%), confirming periodic deposition of sediments enriched in K-bearing minerals. Exchangeable and soluble K contents were classi fied as high, although only 4% of total K is readily available. Contrary to the initial hypothe sis, the silt fraction (rather than the clay fraction) constituted the main compartment of K fixa tion, mediated exclusively by vermiculite. The clay fraction exhibited net K release, attributed to illite alteration. The mineralogical transformation sequence biotite → vermiculite → illite → kaolinite reflects progressive weathering stages that directly influence K dynamics. It is concluded that an integrated understanding of pedogeochemical processes controlling both salt accumulation and nutrient dynamics provides a scientific basis for more realistic taxo nomic classification, improved environmental risk assessment, and the development of more effective management strategies for irrigated agriculture in the Brazilian semi-arid region.

Não se aplica.

The use of silicon (Si) has stood out as an effective tool for reducing the impacts of water stress on plants. However, there is still a need to investigate the sources, residual effects and ideal doses for sugarcane cultivation. In this sense, this research aimed to evaluate the physiological, nutritional and growth responses of the crop to the residual effect of fertilizer derived from amorphous silica (FSA) in mitigating the damage caused by water stress in ratoon sugarcane. The experiment was conducted in randomized blocks with a 4 x 2 factorial scheme, with four replications, during a period of 150 days after cutting (DAC) corresponding to four residual rates of fertilizer derived from amorphous silica, corresponding to 0.0; 78.0; 117.0, and 156.0 kg ha-1 of Si and two levels of soil moisture (40% and 80% of the maximum water retention capacity). Evaluations were carried out on growth parameters (height - SH and stalk diameter - SD, number of plants - NP and leaf area - LA), biomass (fresh mass - LFM and leaves dry mass - LDM; fresh mass - SFM, and stalk dry mass – SDM), biochemical (chlorophyll fluorescence, photochemical quantum efficiency - Fv/Fm, chlorophyll quantification – Chl a+b and carotenoids), physiological (water relations and gas exchange) and nutritional (Si, N, P, K and C in the plant). The water regime of 80% of MWRC with a dose of 156 kg ha-1 promoted increases in SH (+27.60%), SD (+5.87%), LA (+126.10%), LDM (+34.05%) and SDM (+78.40%), respectively, compared to 40% of MWRC. At 140 DAC the Fv/Fm ratio presented values of 0.66 and 0.71 for 40 and 80% of MWRC, respectively, at a dose of 156 kg ha-1. Chl a+b levels showed increases of 66.28% (40% of MWRC) and 55.21% (80% of MWRC) at a rate of 156 kg ha-1 compared to 0 kg ha-1. At 140 DAC, the water regime of 80% of MWRC with 156 kg ha-1 promotes increases in photosynthesis (+16.93%), transpiration (+25.35%) and internal CO2 concentration (+ 34.46%), in relation to 40% MWRC. The leaf Si contents were 2.47 and 6.64 g kg-1 for rates 0 and 156 kg ha-1, respectively. A rate of 156 kg ha-1 combined with 40% MWRC promoted an increase in contents of N (+27.14%), P (+84.60%) compared to a rate of 0 kg ha-1, respectively. The order of extraction and export of macronutrients and Si by the variety RB041443 was: K > N > Si > Ca > P > Mg, in both MWRC. It is concluded that the residual effect of increasing silicon rates mitigated the impacts of water stress in ratoon sugarcane by promoting osmotic adjustment, reducing electrolyte leakage and leaf water potential, and improving gas exchange, photosynthetic pigments, and chlorophyll fluorescence. These effects contributed to greater biomass accumulation and increased foliar nutrient content. These findings provide a technical basis for improving the sustainable management of sugarcane in regions with irregular rainfall distribution, resulting in greater drought tolerance and improved crop performance.

Shallow solums, defined as solums with depths of less than 50 cm, occupy vast areas of the semi-arid region of Pernambuco. In the current context of climate change, the search for sustainable land use strategies that meet the needs of small farmers in semi-arid regions has gained prominence. Among the components of semi-arid landscapes, shallow solums stand out; however, their agricultural potential is often underestimated due to their limited depth, leading many funding agencies to consider them unsuitable for agriculture. Although various characteristics of the regolith are recognized as contributing to the agricultural potential of soils, the influence of the saprolite underlying shallow solums remains poorly understood. Therefore, this study aims to characterize the morphological, mineralogical, physical, and chemical attributes of shallow solums and their respective saprolites derived from crystalline rocks in the semi-arid region of Pernambuco. To this end, samples of shallow soils and their respective saprolites were collected from different crystalline rocks in three profiles located in the municipalities of Gravatá, Serra Talhada, and Floresta (PE), aiming to cover a climatic gradient with different semi-arid contexts. In the field, morphological descriptions and classifications of the solum–saprolite systems were carried out. Deformed and undeformed samples were then collected for physical, chemical, and mineralogical analyses in the laboratory, following the standard methodologies of Embrapa (2017). In the physical properties, an increase in clay content was observed in the saprolitic horizons of the Entisol, while in the Planosol and Luvisol, the highest clay contents were found in the Bt horizon and remained high in the saprolites. Total sand was higher in the A horizon and in the saprolites, with a predominance of the coarse fraction. Dispersed clay content followed the clay levels, being higher in the Bt and Cr1 horizons of profiles 2 and 3, and lower in profile 1. The degree of flocculation was low in all profiles, especially in profile 3, indicating a greater risk of dispersion and erosion. Soil bulk density was lower in the solum horizons of profiles 1 and 2, and in all horizons of profile 3, with greater limitations found in the saprolite. Porosity was higher in the solum horizons and reduced in the saprolite. The chemical attributes revealed high levels of exchangeable bases in the saprolitic horizons, with a potential CEC ranging from 98.8 mmolc kg⁻¹ in the Litholic Entisol to 504.5 mmolc kg⁻¹ in the Chromic Luvisol, as well as low concentrations of Al³⁺, low exchangeable sodium percentage (ESP), and high phosphorus values, especially in the Haplic Planosol, reaching 387 mg kg⁻¹. These characteristics indicate that saprolites can enhance nutrient retention capacity and the availability of essential elements for crop development in areas with shallow solums. The presence of roots in the saprolite reinforces the importance of these horizons beneath shallow solums. Mineralogical analysis showed that the saprolites contain 2:1 clay minerals, such as smectites and vermiculites, as well as primary minerals from the mica and feldspar groups, which can serve as nutrient reserves. It is concluded that, although shallow solums present specific limitations, particularly related to physical attributes, the saprolitic horizons reveal favorable chemical characteristics that can contribute to expanding the agricultural use of these soils in the semi-arid region. These potentialities are especially relevant for peasants and small farmers who manage such areas in the drought polygon.

Population growth has led to a significant increase in daily waste generation, putting pressure on environmental resources and causing degradation processes that result in reduced organic matter content in soils. This problem is aggravated by sugarcane cultivation, especially in sandy soils, requiring mitigating measures. The application of organic waste has emerged as a solution, with particular emphasis on sewage sludge and biochar, which have great agricultural potential. In this context, the objective of this study was to evaluate the impacts of the use of sewage sludge and its biochar on the chemical and biological characteristics of a sandy soil, as well as on the initial development of sugarcane. The experiment was conducted in a greenhouse with a completely randomized design containing 7 treatments (sewage sludge biochar at a dose of 20 t ha-1 (B20); sewage sludge at a dose of 40 t ha-1 (L40); mineral fertilizer (NPK); 40 t ha-1 of the combination of biochar + sludge in the proportions 50%:50% (B50:L50), 75%:25% (B75:L25), 25%:75% (B25:L75); and control). Soil samples were collected at 7, 15, 30, 60 and 120 days to evaluate microbiological (biomass carbon (Cmic), basal respiration (C-CO2), metabolic quotient (qCO2) and microbial (qMic)) and chemical (ammonium (NH4+), nitrate (NO3-) and available phosphorus (P)) parameters. Total organic carbon (TOC) and particulate organic carbon (CMOP) and their stocks were also evaluated, in addition to the collection of diagnostic leaves for nutritional evaluation and of the plant to estimate dry matter production. The initial development of sugarcane was evaluated through biometric analyses, consisting of stalk height (AC), stem diameter (DC) and number of tillers (NP), with four measurements every 30 days after planting. Sewage sludge alone (L40) showed better estimates of Cmic (273.34 mg kg-1), qCO2 (0.27 mg C-CO2 mg-1 Cmic day-1) and qMic (2.71%) at 15 days, indicating that there was greater microbial efficiency in the use of C from this organic source and at this applied dose. The highest values of NH4+ and NO3- were for treatments B25:L75 (12.15 mg kg-1 at 7 days) and L40 (38.51 mg kg-1 at 30 days), respectively. For P levels, all treatments with sewage sludge and biochar were efficient in its availability, with emphasis on B75:L25 (62.36 mg kg-1) at 15 days. Treatment B20 presented the highest TOC contents (14.72 g kg-1) and TOC stock (45.32 ton ha-1) in relation to the others, except when compared to L40. On the other hand, B20 showed the lowest value for CMOP and CMOP stock, with approximately 41.52% and 34.66% lower than the control, respectively, which demonstrates the great stability of the biochar used. There was a limitation in the nutrition of sugarcane, with results lower than the minimum recommended levels. However, the results were similar to NPK and higher than the control, which confirms the nutritional value of sewage sludge and its biochar. The biometric parameters did not show significant differences, except for AC, with higher values for B20 (209 cm) and NPK (206 cm) at 120 days. For dry matter, all treatments were superior to the control, with a difference of up to 99.40% being noted between B75:25 and the control, with the highest and lowest average values, respectively. It is concluded that the applied dose of sewage sludge and its biochar can influence the chemical and microbiological characteristics of the soil, with emphasis on L40, which allowed positive results in most of the parameters evaluated.

The determination of heavy metals in soil is fundamental for studies of environments under suspicion of contamination. Spectrometry, using equipment based on atomic absorption (AA), optical emission (ICP-OES) or mass (ICP-MS), is the most widely used technique for this purpose. However, for determination, it is necessary to open the sample with concentrated acids, generating hazardous waste and destroying the sample. The aim of this study was to evaluate the performance of portable X-ray fluorescence equipment FRXp in determining the elements Ba, Cr, Cu, Fe, Pb, Mn, Ti, V and Zn in soils, compared to ICP-OES. A total of 142 soil samples from the metropolitan region of Recife were used, which were crushed and sieved (200 mesh), and had their metal concentrations determined using both instruments. The results indicated that FRXp showed a high correlation for Ba, Cu and Mn and approximate values for Cu and Mn. However, V, Zn and Cr showed low coefficients of determination and weak correlations in the validation, demonstrating that the FRXp was not effective for their quantification despite the calibration used. The greatest discrepancy was observed for Ni, whose values were inconclusive due to the low content of the element in the FRXp samples. The differences between the methods can be attributed to matrix effects (chemical or physical) and the detection limits of FRXp. It is concluded that, although FRXp has potential for Ba, Cu and Mn analysis, its accuracy depends on rigorous calibration and individualized approaches for each metal, soil type and element content in the sample.

Corn (Zea mays L.) is widely cultivated in Brazil, with its production reaching over 130 million tons in 2023. However, this high productivity requires intensive use of fertilizers and irrigation. A solution to reduce fertilizer dependency and its negative impacts is the inoculation of microorganisms, such as arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB), as well as the addition of biochar, which can enhance the activity of these microorganisms in soil. Thus, this study hypothesizes were: (I) PSB inoculation increases P bioavailability in maize cultivation under greenhouse conditions; (II) AMF inoculation enhances phosphorus uptake in maize; and (III) the application of sewage sludge biochar to the cultivation substrate has positive effects on maize development. The study aims to evaluate the effect of co-inoculation of AMF and PSB, along with the addition of sewage sludge biochar to the plant-growing substrate. The experiment was conducted in a greenhouse at the Federal Rural University of Pernambuco, using a completely randomized experimental design with a factorial arrangement, comprising eight inoculation treatments and two doses of biochar, with four replications. After 62 days, the experiment was collected, and soil, aerial plant parts, and roots were stored. Plant growth parameters, nutrient content in plants and soil, enzymatic activity, and microbiological aspects such as mycorrhizal colonization, microbial biomass carbon and phosphorus, and basal respiration were evaluated. The results partially supported the hypothesis that the co-inoculation of AMF and PSB promotes growth and nutrient absorption, as the co-inoculation resulted in higher mycorrhizal colonization rates and increased nitrogen absorption, but did not promote higher phosphorus accumulation in the plant. Moreover, biochar had a negative effect on AM development and the production of glomalin-related soil proteins, despite promoting higher carbon in the microbial biomass in soils with B. cereus and AMF.

Brazil is the world’s largest producer of sugarcane, playing a pivotal role in the supply of both biofuels and food, with strong implications for the socioeconomic landscape. Although the main production hub is located in the Center-South region, Northeastern states such as Alagoas, Pernambuco, and Paraíba also stand out. The expansion of monocropping has intensified soil-related problems, particularly in sandy soils—characterized by low organic matter content, low water retention capacity, and high permeability. In this context, the application of organic material through conservation practices, such as the use of cover crops, is recommended. Grasses of the genus Brachiaria are particularly suitable due to their high adaptability, efficient nutrient cycling, and substantial biomass production. Therefore, investigating these systems in sandy soils is essential, with emphasis on different seeding densities of Brachiaria grass, in order to optimize management practices and promote the sustainability of agricultural production through the selection of the most appropriate densities. Based on this premise, the objective of the present study was to evaluate the effect of Brachiaria as a cover crop in sugarcane cultivation on soil aggregation and carbon storage in sandy soil. The study was conducted at the Giasa Sugar Mill, located in Pedras de Fogo, Paraíba State, using a randomized block design in a split-plot arrangement with four replications. The main plots consisted of seeding densities of Brachiaria grass: 0 (D0), 10 (D10), 30 (D30), and 50 (D50) kg ha-1 of sown seeds. The subplots were defined by soil sampling depths: 0-10 cm (P1), 10-20 cm (P2), and 20-40 cm (P3). Both undisturbed soil blocks and disturbed soil samples were collected. The experimental area was subjected to physical and chemical characterization. Total organic carbon (TOC), particulate organic carbon (POC), and mineral-associated organic carbon (MAOC) contents and stocks were determined, along with the distribution of macroaggregates by size classes using wet sieving. Data were analyzed through analysis of variance (ANOVA) with the SISVAR software. The F-test was applied, and when significant at the 5% level, the LSD test was used for mean comparison. The contents and stocks of carbon fractions were analyzed individually to assess the effect of seeding density. Significant effects were observed for the different carbon fractions in both contents and stocks, with D10 and D30 standing out. Regardless of treatment, MAOC accounted for the largest share of carbon, ranging from 88.51% (D30) to 90.73% (D10). Seeding density influenced the mean geometric and mean weighted diameters, while depth affected the aggregate stability index. In the extra-large macroaggregate class, D10 and D30 exhibited the highest proportions. Overall, across all macroaggregate size classes and sampling depths, the highest stocks of TOC and POC were associated with seeding densities of 10 and 30 kg ha -1 of Brachiaria grass. The proportion of extra-large macroaggregates was greater in the surface layers. The use of Brachiaria as a cover crop in sugarcane cultivation positively influenced soil aggregation and carbon accumulation in its fractions under sandy soil conditions in the short term. Seeding densities between 10 and 30 kg ha-1 of Brachiaria are recommended for cover crop systems, as they provided superior performance in most of the evaluated variables.

Anthropic activities have been and continue to be responsible for the exponential emission of carbon dioxide (CO₂) into the atmosphere, contributing to climate change. One of the mitigation strategies for atmospheric CO₂ involves soil carbon storage under conservation management systems, such as silvopastoral systems, which can be enhanced by the use of leguminous trees. Understanding soil carbon stocks is directly related to the dynamics of soil organic carbon and to microbial activity, which drive nutrient cycling and the formation of soil organic matter (SOM). Thus, the objective of this study was to quantify nitrogen and total carbon stocks, as well as carbon associated with SOM fractions, and to evaluate microbiological indicators in a silvopastoral system composed of signal grass (Urochloa decumbens Stapf.) intercropped with the leguminous tree sabiá (Mimosa caesalpiniifolia Benth.). The study was carried out in Garanhuns, Pernambuco, Brazil, in an experimental area of 9,18 ha, using a randomized block design with three replicates evaluating: silvopastoral system formed by signal grass and double lines of sabia spaced 25m, sabiá monoculture, and signal grass monoculture with and without fertilization. In the silvopastoral system, four distances were considered concerning the double row of legumes: 0 m (between the double rows), 3 m, 6 m, and 12,5 m. Soil samples were collected at 0-10, 10-20, 20-40, 40-60, and 60-100 cm layers to estimate carbon and nitrogen concentrations and stocks, SOM fractions, microbial biomass, and basal respiration. Soil depth had an effect (p < 0,1) on microbiological indicators, C and N concentrations, and soil organic carbon fractions. Systems influenced (p < 0,1) the accumulated N stock in the 0-40 cm layer, and both systems and distances from the double row of legumes affected the hot-water-extractable carbon fraction (p < 0,1). Distances from the double row of legumes affected the 0-100 cm stocks of hot-water-extractable carbon, as well as the 40-100 cm stocks of particulate organic carbon. Microbial biomass carbon ranged from ±199 mg kg⁻¹ (20-40 cm) to ±140 mg kg⁻¹ (60-100 cm) in the silvopastoral system. Basal respiration remained below ±46 mg kg⁻¹ day⁻¹ throughout the profile and, together with qCO₂, did not indicate oxidative stress for the microbiota. In the silvopastoral system, the accumulated stocks were ±119 Mg ha⁻¹ of C (0-100 cm) and ±7.90 Mg ha⁻¹ of N, with ±4.55 Mg ha⁻¹ in the 0-40 cm layer, equivalent to the observed for fertilized signal grass monoculture. Shorter distances from the double row of legumes favored greater labile carbon stocks (0-100 cm), while particulate organic carbon totaled about 6.27 Mg ha⁻¹, with the highest accumulation at 40-100 cm observed 6 m from the rows (±2.73 Mg ha⁻¹). Silvopastoral systems with legumes increase N stocks and favor soil C sequestration. In addition, these systems promote lower CO₂ flows and favor the stabilization processes of organic matter, through carbon associated with minerals and the humin fraction.

The objective of this research was to evaluate the nutritional status of the mango cultivars Tommy Atkins, Kent and Palmer using the DRIS and CND methods, and to verify the correlation of the DRIS indices with attributes of different soil types in the Sub-Middle region of the São Francisco Valley. The study was carried out in commercial mango orchards on five farms of the company Agrobras Agrícola Tropical do Brasil Ltda. 85 mango plots were selected, 33 of which were from Tommy Atkins, 32 from Kent and 20 from Palmer. The database consisted of productivity and leaf contents of the nutrients N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, Mo and Ni. To separate the reference population, three criteria were used as the database cutoff point, based on the mean productivity + standard deviation: criterion 1 (mean); criterion 2 (mean + 0.5 standard deviation); and criterion 3 (mean + standard deviation). The high-productivity population was used to establish the DRIS standards. The means, standard deviations and variances of each nutrient and of all possible bivariate relationships between nutrients were calculated. All variance ratios between low and high productivity groups were also calculated. The bivariate relationship with the highest variance ratio was selected as the DRIS norm. After establishing the DRIS norms, the DRIS functions and finally the DRIS indices were calculated. To use the CND method, the following were calculated: the filling value, the geometric mean of the nutrients studied, the multivariate relationship between nutrients, the CND norms and the CND indices. The average nutritional balance index (IBNm) was also calculated. The DRIS and CND indices were interpreted according to the Fertilization Response Potential (FRP). Optimal levels of each nutrient were estimated by regression analysis between the nutrient concentration in the leaf and its respective DRIS and CND index. The optimal ranges were established based on the optimal content ± 2/3 of the standard deviation of the nutrient in the reference population. The chi-square test was applied to assess whether there was an association between the DRIS and CND diagnoses. Principal component analysis (PCA) was used to verify the relationship between DRIS indices and soil attributes of three farms. Criterion 2 proved to be the best method for dividing the database. Specific DRIS standards for each of the studied cultivars were established. Optimal nutrient contents and optimal ranges, at the leaf level, were established for each cultivar. The DRIS and CND methods showed high agreement in nutritional diagnosis, but the DRIS method proved to be more sensitive in detecting nutritional imbalances, since it was more correlated with the nutritional indices compared to CND. The most limiting nutrients by deficiency were Cu, Mn, Zn and Mo, while the most limiting nutrients by excess were Cu and Mn. The DRIS indices ICu and IK, IS, IMn and INi showed positive and negative correlations with the P, K, Ca, Mg, Cu, Mn, Zn and T contents, respectively, for the more clayey (Agrobras 01) and more sandy (Hidrotec) soil conditions. Future studies should be conducted with the aim of establishing specific DRIS standards considering not only the cultivar, but also each soil type. Experiments should focus on validating the established DRIS standards.

Soil contamination by heavy metals is a significant environmental and agricultural issue, arising from mineral resource exploitation and industrial activities, with severe impacts on public health and sustainability. The persistence of these pollutants in soils, particularly in underdeveloped countries, necessitates the investigation of effective and accessible strategies to mitigate their effects. This study aimed to evaluate the potential of biochar in remediating soils contaminated by heavy metals, focusing on reducing the mobility of these pollutants, improving soil fertility, and promoting the growth of cultivated plants. Additionally, it examined the effects of modifications applied to biochar on its influence on these attributes. Soil incubation experiments were conducted using different types of biochar (rice husk, sugarcane bagasse, sewage sludge, and filter cake), assessing which biochars showed the highest potential for metal immobilization in soil. Subsequently, vegetables were cultivated in soil polluted by cadmium (Cd) and amended with biochar, and sorghum was grown in soil contaminated by metallurgical slag and treated with biochars. Soil and plant samples were analyzed to determine the levels of heavy metals, nutrients, and biomass. Furthermore, the influence of silicon (Si) in mitigating metal toxicity was evaluated. The results demonstrated that biochar application reduced the availability of cadmium (Cd) and lead (Pb) in soil by transferring them to less bioavailable fractions and decreasing their absorption by plants. Improvements in soil fertility were observed, including increases in pH, soil organic matter, and nutrient availability. Plant growth was also enhanced, with increased biomass production and silicon absorption, which augmented tolerance to heavy metal effects. Biochars derived from sewage sludge (BLE) and filter cake (BTF) yielded the best results. This study highlighted the potential of biochar as a sustainable tool for remediating contaminated soils and promoting food security and environmental protection. Combining biochar with phytoremediation emerges as an effective strategy for recovering degraded areas.

Semiarid region has edaphoclimatic conditions that prevent the accumulation of soil organic matter (SOM). SOM is a key attribute for assessing soil health and quality. Therefore, conservation practices such as the use of mulch, intercropping with adapted species, and reuse of treated sewage water should be used in the Brazilian semiarid region. Thus, the objective of this study was to evaluate the development and productivity of forage cactus (Opuntia stricta) and intercropping with buffel grass (Cenchrus ciliaris L.) and sorghum (Sorghum sudanense (Piper) Stapf.), as well as to determine the contents and stocks of labile and recalcitrant C in the soil in areas with 0, 8, and 12 Mg ha-1 of mulch, irrigated with treated sewage water. For this purpose, a survey was carried out at Fazenda Primavera, Parnamirim-PE. The experiment was divided into two distinct moments: one that evaluated forage cactus without intercropping and another considering intercropping. Soil samples were collected in the experimental area and in the native vegetation area (VN) (Caatinga) at 0-10, 10-20 and 20-40 cm. VN was used as a comparative basis. Analyses of total carbon (TOC), particulate carbon (POC) and associated with minerals (MAOC), carbon extracted in hot water (C-aq H2O) and carbon extracted in permanganate (C-KMnO4) and their respective stocks (Est) were performed. In addition, the production of fresh matter (FM) and dry matter (DM) of forage cactus, sorghum and buffel grass was quantified, as well as biometric evaluations of forage cactus. The results for the first moment showed that management with treated sewage water and the use of 8 and 12 Mg ha-1 of mulch favor higher productivity and EstC, surpassing the results of areas without mulch, especially when using 12 Mg ha-1. For EstC the behavior was NV > SS12 > SS8 > SV > NC. For EstPOC SS12 > SS8 > SV > NC > NV, for EstMAOC NV > SS12 = SS8 = SV < NC. For EstC-aq H2O and EstC-KMnO4, the treatments did not present statistical difference compared to NV or among themselves. The FM and DM productivity of the cactus forage with 12 Mg ha-1 of mulch was 3.3 and 3.4 times higher in relation to NC. Regarding the second moment: at the total stock level (0-40 cm), the use of 8 Mg ha-1 of mulch favors a value 37% higher than 0 Mg ha-1 (with sorghum); for buffelgrass, no significant increases were observed with the use of mulch rate. The productivity of the intercrop was higher for forage cactus+sorghum with 12 Mg ha-1 of mulch. The FM ranged from 104.7 to 169.5 Mg ha-1 (forage cactus+sorghum), and for forage cactus+buffelgrass, the DM was between 73.6 and 108.7 Mg ha-1 (both 8 and 12 Mg ha-1 of mulch, respectively). For forage cactus+sorghum, the DM ranged from 4 to 10 Mg ha-1, and for cactus forage+buffelgrass, the MS ranged from 3 to 5 Mg ha-1, both in relation to the treatment without mulch. The different cuts of sorghum and buffel grass show that the use of 12 Mg ha-1 favors greater productivity, especially the second cut, reaching values of 12.2 and 4.6 Mg ha-1 (FM and DM of sorghum, respectively) and 11.9 and 5.3 Mg ha-1 (FM and DM of buffel grass, respectively). Therefore, in semi-arid conditions, the above-mentioned conservation practices are viable alternatives to promote sustainable development.

Population growth has increased the demand for food, leading to the generation of large volumes of agricultural and agro-industrial residues. The sustainable management of these residues poses a challenge to the implementation of efficient and sustainable agricultural practices. In this context, the reuse of residues particularly in the form of biochar, a carbon-rich product can enhance soil properties and reduce environmental impacts. Although biochar stands out for its versatility in agricultural and environmental systems, its interaction with soil microorganisms, especially those belonging to the Trichoderma genus, still needs to be better understood. Trichoderma species are widely recognized for their efficiency in the biological control of phytopathogens and their role as plant growth promoters. However, studies addressing the interaction between biochar and Trichoderma remain scarce, requiring further investigation to understand their impacts on soil microbiota. To fill this gap, the present study aimed to evaluate the effects of biochar produced from grape stalks and fermentation residues, applied in combination with Trichoderma aureoviride URM 5158 and Trichoderma hamatum URM 6656, in soils cultivated with grapevines. Field experiments were conducted using a randomized block design with nine treatments and three replicates. Chemical and microbiological soil attributes and grapevine productivity were evaluated. The results showed that the application of biochar and Trichoderma in soil cultivated with Cabernet Sauvignon grapes led to changes in the structure and diversity of microbial communities. Interestingly, soil chemical variables such as pH, Na⁺, and K⁺ attributed to the biochar input played a modulatory role in the structure of microbial communities, favoring certain groups over others. At the phylum level, fungal communities were predominantly composed of Ascomycota, Basidiomycota, Chytridiomycota, and Glomeromycota key phyla in organic matter decomposition and nutrient cycling. On the other hand, when evaluating the effects of biochar and Trichoderma application on Malbec grapevines with regard to soil chemical and enzymatic attributes, our results revealed that both treatments significantly altered soil properties. The greatest increases were observed with the co-application of grape fermentation biochar (GFB) and T. hamatum (GFB+Th), resulting in expressive increases of 569.23% in microbial biomass carbon (MBC), 60.73% in total organic carbon (TOC), and 86.70% in potassium (K) content. Additionally, the isolated application of GFB biochar increased acid phosphatase activity by 38.76%, while its co-application with T. hamatum enhanced β-glucosidase activity by 56.46%. These findings are relevant to viticulture, as they indicate that the combined use of biochar and Trichoderma may serve as an effective strategy for improving soil health by promoting microbiological balance and increasing nutrient availability.

Mangroves provide valuable ecosystem services and perform essential ecological functions. However, they are increasingly threatened by anthropogenic pressures, particularly contamination from toxic compounds originating from urban, industrial, and port activities. In this context, some of the most relevant contaminants are Polycyclic Aromatic Hydrocarbons (PAHs), Rare Earth Elements (REEs), and heavy metals, all of which exhibit significant geochemical dynamics in mangrove soils. This study aimed to assess the contamination, vertical distribution, and potential sources of PAHs in mangrove soils impacted by the oil spill that occurred along the northeastern coast of Brazil. It also sought to evaluate the soil and geochemical factors influencing their retention and mobility, as well as to analyze the presence, behavior, and distribution patterns of REEs and heavy metals associated with redox dynamics and iron geochemistry in these soils. Eight soil profiles were collected along the Ipojuca River estuary in Pernambuco, Brazil, and sectioned into six layers. Integrated analytical approaches were used, including gas chromatography, mass spectrometry, and physical, chemical, and sequential iron extraction analyses. The results indicated moderate PAH contamination, with a predominance of high molecular weight (HMW) compounds linked to both pyrogenic and petrogenic sources. The vertical distribution of PAHs showed higher concentrations in surface layers, influenced by edaphic characteristics such as total organic carbon (TOC) content and particle size. REEs and heavy metals were correlated with amorphous iron forms and sulfides, highlighting the role of iron geochemistry in their retention and mobility. The alternation between redox conditions in mangrove soils, typical of tidal environments, was crucial for the coprecipitation and release processes of these contaminants. This study contributes to advancing the understanding of geochemical processes in tropical mangroves and their associated environmental risks, providing a scientific basis for monitoring, remediation, and conservation strategies for these sensitive ecosystems.

From the 1980s onwards, the semi-arid region of Bahia was projected as a promising area for sugarcane cultivation. However, the region is very dependent on irrigation and the most commonly used technique is fertigation. The distribution of fertilizers in this type of irrigation is used according to the accumulation of nutrients. The data currently used in the region are based on crops under different conditions, such as rainfed and conventional irrigation, different cultivars, or even data from regions with completely different climates from the semi-arid northeastern region. In addition, soils and the possibility of perennial crops, with longer cycles, require more detailed studies that can guide the adequate supply of fertilizers. Thus, it is believed that the sugarcane varieties and cultivation cycles (plant and ratoon) have different nutritional demands, interfering with the efficient management of nutrients in fertigation, especially in different soils. In this context, the objective of this work is to evaluate nutrient demand, biomass accumulation and nutritional efficiency of sugarcane varieties cultivated under fertigation in different cultivation cycles and soils. The study will be carried out in the agricultural area of Usina Agro Indústrial do Vale do São Francisco S.A – AGROVALE, located in the mesoregion of Vale do São Francisco in the semi-arid region of Bahia. The experimental area will be composed of three types of soils, Orthic Haplic Vertisol, Sodic Haplic Cambisol and Tb Eutrophic Haplic Cambisol. Where the nutritional demand and efficiency of two sugarcane varieties (VAT902012 and RB961003) will be evaluated during two cycles (cane plant and ratoon). The soils will be characterized physically and chemically and the varieties will be sampled at 60, 120, 160, 200, 260 and 360 days after planting (DAP), where the biomass will be measured and the levels of N, P, K, Ca, Mg, S, Fe, Cu, Mn, Zn, B, Mo, Si and Na. Nutrient demands by sugarcane development stage will be measured by variety, crop cycle and soil type. Combining these data with
those of biomass production, the nutritional efficiency of the varieties per cycle and per cultivation environment will be calculated. The project should generate important information that could guide the use of fertilizers in sugarcane in the semi-arid region of Pernambuco. Agricultural use cannot be dissociated from environmental concern because it is what guides the sustainability of the ecosystem. The inadequate use of fertilizers due to the high demand for nutrients in a high productivity system needs to be carefully evaluated, so that its management is rigorously sustainable.

A comprehensive understanding of the dynamics of various elements and processes occurring in the soil profile is only achieved through the joint study of the soil-saprolite system. This is especially true for rare earth elements (REE), whose unique characteristics allow them to participate in chemical processes and reactions essential to the pedosphere. REE comprise a group of 17 chemical elements, corresponding to Sc, Y and the 15 lanthanide elements, from lanthanum to lutetium. These elements are commonly divided into two groups: light rare earth elements (LREE: La-Sm) and heavy rare earth elements (HREE: Eu-Lu). However, knowledge about the distribution and behavior of these elements in the soil profile is limited, especially in tropical regions, where weathering and pedogenesis processes are intense and variable. In this way, a climate gradient can provide crucial information about the response of these elements to climate variation and its implications for soil and vegetation. Thus, studies that associate climate and REE geochemistry are relevant to the scientific community because they can serve as indicators of important geochemical changes to the environment. Aiming to study the geochemistry of REE in the soil profile, samples were collected from 3 soil profiles (P1 at the base, P2 in the intermediate position and P3 at the top), distributed at different altitudes and, consequently, under a climatic gradient, from a climate drier and hotter at the base to a wetter and colder climate at the top of the Triumph Massif. These samples were prepared and subjected to analysis to determine the content of: 1) total clay, 2) organic carbon (TOC), 3) major elements (Al2O3, BaO, CaO, Cr2O3, Fe2O3, MgO, MnO, P2O5, K2O, SiO2, Na2O e TiO2), 4) minor elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu and Y), 5) pedogenetic Fe (Fed) and 6 ) forms of iron linked to low crystallinity phases (Feo). Chemical weathering measurement indices were calculated, relationships between REE were calculated, normalization of REE in relation to the “upper continental crust” (UCC) was performed and the content of total clay, TOC and pedogenetic iron forms were correlated with the contents of LREE and HREE in the respective soil profiles. The relationship between climatic variation and the geochemistry of the profiles was evident and influenced the attributes measured in the profiles in the three positions: 1) the highest levels of larger more mobile elements such as K were determined in P1, due to lower rainfall in this position, 2) the weathering indices indicate more intense weathering in the position with the highest precipitation in P3, 3) the normalization of the REE indicated the enrichment of the LREE, depletion of the HREE and positive Eu anomaly in P1 and P2, thus as uniformity in P3, probably due to greater humidity at the top, 4) the climatic gradient affected the distribution of pedogenic iron forms in the profiles and Feo had higher content in P1, under semi-arid climate, just as Fed had higher content in P3 under climate humid, 5) the clay content varied from P1 to P3, due to the effect of climate on weathering, 6) organic matter was incorporated in different ways, depending on the position of the profile in the climatic gradient, with a drastic decrease in depth in P1 and moderate in the other profiles, 7) LREE correlated well with clay content, Feo and Fed and 8) HREE correlated well with TOC. The data indicate that the climate gradient significantly shapes the geochemistry of syenite-derived soil profiles, making this an important result for studies that aim to relate climate to REE geochemistry in soil profiles around the world.

The vegetation of the Brazilian semi-arid is predominantly constituted by Caatinga. In recent years, changes in the use of land, through anthropic practices such as livestock, firewood extraction and mineration, have contributed for the degradation process of these areas, strongly affecting the soil's capacity of store carbon. The benefits of revegetation in degraded areas involve the entirety of the ecosystem and contribute to environmental balance. Based on this context, this research aimed to evaluate the quality and carbon input of soils in areas under native Caatinga vegetation, pasture, and in the process of revegetation for five years with native species and Atriplex nummularia. In all areas, soil samples were collected at the end of the dry and rainy seasons. Ten mini trenches 50 cm deep were opened, and soil samples were collected (0-5, 5-10, 10-30, 30- 50 cm), for the purpose of evaluate the physics, chemical and biological attributes of the soil. The pH in water (1:2,5), electrical conductivity and soluble cations (Ca2+, Mg2+, Na+, K+) in the soil samples will be determined. Soil density, granulometry and total porosity will also be determined to evaluate the physical attributes. The contents of total organic carbon (wet oxidation), carbon stock, water-soluble carbon, and labile carbon will be determined according to the depth of the soil in areas under different vegetation covers. To evaluate the biological quality, the contents of total organic carbon (wet oxidation), carbon stock, carbon management index, permanganate oxidizable carbon as a function of soil depth in areas under different vegetation covers. For the biological analyzes, samples were collected only in the 0-5 cm layer and determined the microbial biomass carbon, soil metabolic quotient (qCO2), microbial (qMic) and mineralization (qMin), respirometry, and humic substances, the AH: AF and HUM ratio being calculated. The results indicated that the soil has a sandy texture, with higher density for degraded pasture and revegetation areas. There were salt concentrations and cation accumulation in the revegetation due to the history of degradation of the regenerated area. CBM and C-Mic and RB differed between seasons, where the dry season presented higher contents, The TOC and POC contents were higher in the rainy season and the POC still varied between the areas, Caatinga> Revegetation> Degraded pasture, respectively. In relation to the humic substances, in the surface layer, HUM> AH> AF. They also differed between seasons, presenting higher values in the humid season. As well as the TOC stock, the lowest OC values in the degraded pasture area suggest that management is negatively impacting soil organic matter and quality. In general, it is possible to observe improvements in the area under revegetation, even with the adversities that occur in the experimental area and that the areas may take decades to be regenerated.

Sugarcane ethanol is an alternative renewable fuel source with a higher energy balance than other crops, but its production generates a large volume of vinasse that requires appropriate management. The application of vinasse can favor the biological characteristics of the soil, mainly the activity of enzymes related to carbon (C) and sulfur (S) cycling due to its high organic matter content. Furthermore, it can be an alternative for partial or total replacement of mineral fertilizers, or a vehicle for nitrogen fertilizer. Nitrogen (N) added to vinasse consists of the enrichment technique that favors fertilizer distribution. There is evidence that the association of vinasse with N-urea fertilizer reducing reduce ammonia (NH3) emissions into the atmosphere, but losses can still be significant. The use of compounds that inhibit the urea hydrolysis process has the potential to reduce NH3 losses. However, , there are no studies using urease inhibitors (UI) in enriched vinasse, as well as the short-term effect on biological activity after adding vinasse enriched with urea and urease inhibitors. Therefore, the present study aims to evaluate the efficiency of urease inhibitors in reducing NH3 emissions from the application of vinasse enriched with N-urea and the potential of management in increasing the activity of β-glucosidase and arylsulphatase. The study was conducted in the Northeast region of Brazil under controlled greenhouse conditions. The experimental design followed the randomized block model. The treatments were: 1) Control; 2) Urea - UR; 3) Vinasse + Urea – V + UR; 4) V + UR + NBPT and 5) V + UR + H3BO3. The ammonia volatilization observed with the use of solid urea was 12.55% of the applied N, stimulated by the high urease activity in the straw and urea-N retention in the straw. The addition of urea to vinasse was efficient in reducing NH3 losses and presented losses of 1.83% of the applied N. Urease inhibitors (NBPT and H3BO3) were not efficient in reducing NH3 volatilization when compared to the application of V + UR. The addition of urea-enriched vinasse (with or without IU) increased β-glucosidase activity but did not alter arylsulphatase activity. In this sense, mixing V with UR can be considered an advantageous strategy to reduce NH3 volatilization and increase the activity of enzymes related to C cycling in soils cultivated with sugar cane in northeastern Brazil. However, the addition of UI did not bring additional benefits from this management system.

Soil quality represents the system's ability to maintain its ecosystem functions, with land use and management having an impact on altering its patterns by changing the system's properties. The aim of the study was to assess changes in soil quality and litter in different land use systems of native Caatinga vegetation, according to soil properties and changes in its use. Six bimonthly soil samples were collected from July/2023 to May/2024 in the 0-20 cm layer in areas under different land uses in the municipality of Caruaru-PE. At the Instituto Agronômico de Pernambuco (IPA), samples were taken from areas under native forest (FN₁), tillage with the use of fire (LWF) and tillage without the use of fire (TIL). At Fazenda Santa Maria (FSM), samples were collected from areas under native forest (FN₂), pasture with high animal stocking (PHS) and pasture with low animal stocking (PLS). Leaf litter was only collected in the native areas. Soil quality indices (SQI) were calculated for physical, chemical and biological properties, as well as ecosystem functions. Leaf litter production, water content, C:N ratio, microbiological properties and material stability were assessed. The soils under uses FN₁ and FN₂ had the best SQI, followed by uses TIL and PLS with intermediate indices and LWF and PHS with the lowest SQI. Leaf litter production was 4,30 t ha^-1 and was lowest in the rainy season. The litter from FN₁ had a lower C:N ratio and higher humidity, microbial biomass and basal respiration, contrary to what was observed for FN₂. The change in land use led to a reduction in the quality of its properties and the ecosystem functions assessed, with the loss of organic carbon acting as a key element in this process. The microbiological activity of the material was higher in the dry season, with its presence and dynamics acting on the soil properties. It can be concluded that land use conversion and the exclusion of litter are factors that reduce soil quality and its ability to maintain ecosystem functions. The adoption of management practices with less impact on soil properties, or the preservation of native forests, are measures that maintain its environmental quality.

In the quest for sustainable and efficient soil management solutions in agricultural ecosystems, understanding the interaction between polymers and various soil types emerges as a fundamental field of study. In particular, polyacrylamide (PAM), an anionic polymer commonly used to enhance soil physical properties and control erosion, presents specific challenges in its application, especially regarding its penetration and effectiveness in the cohesive layers located in soil subsurfaces. This study addresses the interaction of PAM with two soil types, Argissolo Amarelo Distrocoeso epirredóxico and Latossolo Amarelo Distrocoeso, focusing on the dynamics and attenuation of the polymer in the soil profile. The research was conducted in distinct environments - the Tabuleiros Costeiros and Cristalino Meridional - where the physicochemical and mineralogical properties of the soils were evaluated to understand their influence on PAM mobility. Using the Sips isotherm model for adsorption modeling and the Attenuation Factor to analyze the persistence of PAM in the soil, the study integrates chemical, physical, and mineralogical analysis methods for comprehensive understanding. Various treatments were applied, including the addition of silicate and the removal of cementing agents, to observe their influences on PAM adsorption. The research demonstrated that PAM mobility in soils is strongly influenced by the soils' hydraulic, chemical, and mineralogical properties. Moreover, silicate treatments proved effective in enhancing PAM penetration, particularly in the cohesive horizons, highlighting the need to adopt integrated approaches that simultaneously consider the chemical, physical, and mineralogical interactions of the soil to optimize PAM efficacy. These findings expand the understanding of PAM use in agricultural practices and pave the way for more efficient and sustainable soil management methods.

The ultramafic complex in Niquelândia, Goiás, hosts Brazil's largest nickel reserve and is home to endemic plant species capable of accumulating over 1000 mg kg-1 of Ni in their leaves, known as nickel hyperaccumulators. These plants represent a sustainable alternative to ore extraction. The microbiome plays a fundamental role in plant adaptation to the environment, acting as an amplifier of their adaptive capacity. The aim of this study is to investigate the microbiome of the nickel hyperaccumulator plant species Justicia lanstyakii and Lippia lupulina in the ultramafic complex of Niquelândia, using Illumina amplicon sequencing. Additionally, data published in the last five years were analyzed for a meta-analysis of the microbiome in ultramafic soils worldwide, aiming to identify a possible microbial signature in these  environments. A total of 1080 ultramafic soil samples were analyzed globally through meta- analysis, using high-throughput Illumina sequencing data. Research articles available in the  Scopus and Web of Science databases were selected for this analysis. Moreover, amplicon sequencing was performed to investigate the microbiome associated with the rhizosphere of the nickel hyperaccumulator plant species Justicia lanstyakii and Lippia lupulina from the ultramafic complex of Niquelândia, as well as the bulk soil of the plants. Our results revealed significant diversity of phyla, including Acidobacteria, Actinobacteria, Chlorobi, Chloroflexi, GAL15, Mixococota, Nitrospirae, Planctomycetes, Proteobacteria, and Verrucomicrobia, highlighting the richness of these soils. Bulk soil samples showed a predominance of phyla such as Acidobacteriota (23.5%), Spirochaetota (19%), and Chloroflexota (15.93%). In the rhizosphere of J. lanstyakii, the main associated phyla were Actinobacteriota (35.57%), Acidobacteriota (25.5%), and Verrucomicrobiota (17.97%), while in L. lupulina, they were Actinobacteriota (34.73%), Acidobacteriota (21.07%), and Verrucomicrobiota (13.17%). This study highlighted not only the diversity and structure of these microbiomes but also emphasized the notable enrichment and formation of more complex interactions.

The formation of soils in the semi-arid region of northeastern Brazil is strongly influenced by the parent material, due to the low intensity of climatic effects. As a result, the soils formed in this region are predominantly young, showing a greater correlation with their parent material. This region hosts the greatest diversity of soils in the country, including Vertisols, known for their potential for contraction and expansion. The study of Vertisols is essential to understand the mechanisms of carbon stabilization in the soil, especially in the semi arid region, where soil diversity is high, and climatic effects are less pronounced. The stabilization of organic matter is crucial for maintaining fertility and for carbon sequestration, contributing to agricultural sustainability and climate change mitigation. The main objective of this research is to morphologically, physically, chemically, and mineralogically characterize two profiles of Vertisols, aiming to better understand the carbon stabilization and the different mechanisms involved in this process in the semi-arid region. Two soil profiles were selected and collected in Madalena – CE. Disturbed and undisturbed samples were taken and subsequently classified and described morphologically. Profile 1 was classified as ORTHIC EBANIC VERTISOL and profile 2 as ORTHIC HAPLIC VERTISOL. The physical, chemical, and mineralogical characterization included detailed analyses to identify the properties and behaviors of the soils under study, such as physical fractionation of organic matter, FTIR, DSC/TG, and distribution of carbon stock along the profile. Although profiles 1 and 2 have, they exhibit different forms of stabilization. Profile 2 has a greater amount of organic groups compared to profile 1, which directly influences the stabilization of organic matter. On the other hand, profile 1 shows a more pronounced organo-mineral relationship, probably due to calcium (Ca) bridges, which play a significant role in stabilization. The evaluation of the properties of Vertisols significantly contributes to advancing knowledge about these soils in the caatinga ecosystem. This study provides a solid basis for future research, helping to understand the potentialities and limitations of Vertisols in terms of agricultural use and environmental conservation.

Water scarcity is a growing problem worldwide, making it impossible to carry out agricultural practices and economic development, especially in arid and sub-humid regions. The use of wastewater from sewage can be a sustainable measure for this problem, but the inadequate management of this effluent can negatively affect the microbiota. In this sense, the objective of the present work was to evaluate the impact of irrigation with water from reused domestic sewage, mulch and intercropping on the microbiota of soil cultivated with cactus pear. The experiment was installed in the experimental unit in Parnamirim - PE, semi-arid region of Pernambuco. The treatments were a factorial arrangement between two consortiums (Sudanese sorghum – Sorghum sudanense (Piper) Stapf. and buffel grass (Cenchrus siliaris L) and four cover conditions (no cover - SC, natural vegetation - VN, 8 tons of sorghum straw and 12 tons of sorghum straw) with four replications, whose soil received treated domestic sewage effluent water. Soil samples were taken at 0, 4, 8 and 12 months during the monitoring of the experimental area, at depths 0-10 and 10-20 cm. In addition to the chemical and physical characterization of the soil, the following were determined: i- carbon stock (EC), ii- microbial biomass carbon (CBM), iii- microbial biomass nitrogen (NBM), iv- basal respiration of soil (RB), v- metabolic quotient (qCO2) and microbial quotient (qMIC).Irrigation and mulch promoted an increase in basal respiration from 8 and 12 months after the beginning of irrigation with residual water. A positive effect of consortiums was also observed due to the increase in CBM, but this requires a temporal continuity of the biological analyses. The qCO2 made it clear that there was less activity by microbial biomass, which may be a reflection of disturbances caused by the proposed modifications. The qMIC indicated that the microbial biomass was not efficient in the use of carbon over time, and makes clear the need for more time to evaluate the biological attributes.

Sugarcane is one of the most relevant crops in Brazil, mainly because of its great economic importance. With an estimated production of 596.1 million tons in the 2022/2023 harvest, the Brazilian sugarcane agroindustry is an important global exporter of sugar and alcohol. To improve the profitability of the sector, circumvent the labor shortage, and comply with environmental legislation, in the production process, total or partial mechanized harvesting about the traditional method, with previous burning of the sugarcane plantation, has presented itself as the best option, from the economic and environmental quality point of view. From the physical attributes of the soil, it is possible to measure its quality, when modified by different agricultural systems, and to guide management strategies and maintenance of the physical quality of the soil, avoiding its degradation. The objective of this study was to evaluate the structural physical quality of the soil in areas under sugarcane cultivation, with mechanized harvesting systems (raw sugarcane) and previous burning of the sugarcane field. The soil samples for the physical tests were collected in structured (aggregates and volumetric cylinder) and unstructured (auger/shovel: fine air-dried soil - FADS) forms. Thus, the aggregate samples were used to determine the tensile strength of the soil (TS), via bench penetrometer; as well as for the aggregate stability index (ASI) tests, via the wet method. The aggregates for TS were moisture balanced at room temperature; while the aggregate stability parameters (weighted mean diameter, geometric mean diameter, and aggregate stability index) were determined using the Yoder apparatus. Samples in the volumetric cylinder (≅ 100 cm³) were used in the tests of total porosity (saturation method), pore size distribution (macro and micropores, via tension table), and soil density (volumetric cylinder method). In contrast, those in FADS were used to determine particle size and organic carbon of soils. In the aggregates assays two size groups were used, each with three equivalent diameter classes (eq.), being: the first group, measuring 22 and 44 mm, used in the TS assays; and the second, with 5.32; 11.5, and 17.6 mm, for the ASI ones. Each aggregate size class was also used in the tests to determine the representative elemental volume (REV), defined for each attribute studied (TS and ASI). Thus, the delimitation of the REV was based on the size of the aggregate, from which the increase in its volume did not influence the results of the analyzed attribute. Thus, this research found that harvesting under burning promoted changes in the structure of the soil, even on a short time scale, represented by the burning of the vegetation cover in the environment and consequently reducing soil organic matter (SOM), the native forest area presented the best structural values being followed by the cane area without the burning process. The REV was kept in standard sizes (5.32 mm for the wet tests and 22 mm for the TS tests) following the standard established in the literature.

Studying technosols is crucial to understanding their potential for waste management, recovering degraded areas, agricultural production, carbon sequestration, and sustainable use of natural resources. The largest scheelite mine in South America is located in the tropical semiarid region of Northeast Brazil. However, the tailings from this mining activity have been accumulating in the open since the 1940s, causing several environmental problems. Although technosols derived from mining tailings are widely studied in the world, information on the pedogenesis of these soils is scarce in Brazil, especially in the Brazilian semi-arid tropical environment. In this scenario, the objectives of this study were: to understand the pedogenesis of technosols originated from scheelite mining over a chronossequence (0, 2, 5, 10, and 40 years) in the Brazilian tropical semiarid region; ii) to understand the macro and micromorphological evolution of these technosols; iii) investigate changes in their physical, chemical and mineralogical properties of the evaluated technosols; iv) identify the main pedogenetic processes in the studied technosols; v) classify the technosols taxonomically, according to the WRB, with a proposition to the SiBCS. The profiles of technosols constructed from scheelite mining tailings showed macromorphological evolution over the 40-year chronossequence, with increased thickness of surface horizons, clear development of colors and structures, and a more advanced stage of homogenization of their horizons. These results demonstrate the rapid pedogenesis of technosols derived from scheelite mining in the Brazilian semi-arid tropical environment. According to the WRB, the 2-, 5-, and 10-year-old profiles of technosols were classified as Spolic Technosol (Loamic, Alcalic, Calcic, Humic), while the 40- year-old profile was described as Spolic Technosol (Loamic, Alcalic, Calcic, Hyperhumic). Based on micromorphological investigations, substantial developments of specific pedogenetic processes were observed, such as bioturbation, melanization, and pedalization. Over the four decades, there was a progressive increase in the melanization process, accompanied by a high accumulation of organic carbon. Regarding the 0-30 cm depth range, the technosol profile derived from scheelite mining, with 40 years old, showed a carbon stock (131.38 Mg ha-1) superior to the main classes of natural soils in the Brazilian semi-arid region and stored three times more carbon than the average of Brazilian soils. Therefore, the studied technosols have great potential to sequester carbon in the Brazilian tropical semi-arid region and may play an important role in reducing atmospheric CO2 levels and mitigating climate change. he high natural reserve of nutrients in the primary minerals of the fine sand, coarse sand, and clay fractions, such as biotite, feldspars, actinolite, and talc, demonstrates the high potential of these technosols in providing essential elements to plants in the medium term and overcoming the main limitations nutrients for the development of the agricultural activity. Furthermore, the great diversity of minerals (biotite, plagioclase, apatite, microcline, actinolite, epidote, vesuvianite, powellite, carbonate minerals, titanite, and opaque minerals) in the waste-forming materials (tactite, marble, and gneiss) used to build technosols also can be important sources of slow release of nutrients, capable of maintaining the fertility of technosols in the long term. The presence of kaolinite and smectite in all technosols of the chronossequence, including the initial tailings, indicates that the profiles began their development enriched in these phyllosilicates. The formation of goethite was associated with reduced iron activity in the solution, with increased moisture and high concentrations of organic carbon in technosol horizons. Linear discriminant analysis showed a high potential for discriminating technosols originating from scheelite mining tailings, corroborating the rapid pedogenesis of the profiles over the 40-year chronossequence. In light of the scarcity of information on the construction of technosols derived from mining activity in a tropical semi-arid environment, this work provides promising results not only for the scientific community, but also for policy makers on the importance of efficient management of mining tailings. to recover degraded areas, agricultural production and manage waste in semi-arid environments.

Ultramafic soils originate from mafic or serpentinized mafic rocks and correspond to approximately 3% of the earth's surface. Due to its mineralogy, it has high levels of heavy metals and low fertility, which makes it unproductive for agricultural activity. An alternative to low productivity agriculture is agromining, which consists of obtaining economically important metals, such as nickel, through phytoextraction carried out by hyperaccumulating plants. They are able to retain high levels of metals in their tissues. Research has reported that these microorganisms may favor the development of hyperaccumulators by providing nutrients and substances that confer tolerance to the high concentration of metals in the soil. Therefore, the objective of this work was to elaborate a collection of Plant Growth Promoting Bacteria (PGPB) from ultramafic soils and from metal hyperaccumulating plants. For this, bacteria were isolated from samples of rhizospheric soil, from the hyperaccumulator plants Lippia lupulina and Justicia lanstyakii, and from adjacent soil, from Niquelândia - GO. The rhizobacteria were isolated in 10 % TSA medium, had the growth promotion mechanisms characterized and were identified through sequencing of the 16S rRNA gene. Thus, a collection composed of 66 bacteria tolerant to 7.5mM NiSO4 6H2O was obtained. Of this total, 18% produced Indole Acetic Acid (IAA), 26% solubilized calcium phosphate, 47 % performed Biological Nitrogen Fixation (BNF) and 17 % produced siderophores. 45 were genetically identified, of which 31% belong to the genus Bacillus sp., 22 % Alcaligenes sp., 15,55 % Providencia sp., 4 % Enterobacter sp. and 2 % Priestia sp. Therefore, it can be inferred that the elaborated collection has potential for use in future research to improve agromining and phytoremediation of soils contaminated by heavy metals.

The regolith can be composed of soil, saprolite and/or sediments, covering the entire “mantle of weathering” present on the rocks. Regoliths formed by soil-saprolite systems are frequently observed in the pedosphere, the unified study of soil and saprolite makes it possible to understand the dynamics of several geochemical processes that occur in the soil, including those associated with rare earth elements (REE), whose behavior is influenced by the physical, chemical, mineralogical and biological attributes of the regolith. REEs move throughout regolith and are found in multiple minerals, which are released into the soil-saprolite system during weathering processes. Phosphate minerals, among which monazite is found, stand out among those that carry and release REE. Its dissolution releases, in addition to REE, phosphorus, which is one of the main sources of phosphorus readily available to plants. Although there is scientific evidence of the importance of saprolite for understanding the processes that occur in regolith, studies that approach saprolite as part of the regolith or that deeply investigate its properties and potentials are scarce. Therefore, seeking to understand the dynamics and associations that REE make up in the regolith, the present study aimed to investigate the REE geochemistry and its relationship with physical, mineralogical and chemical attributes of soil-saprolite systems, with emphasis on its relationship with the elevated levels of available P in these gneiss-derived regoliths. For this purpose, three points were selected for sampling soil-saprolite systems under a climatic gradient in the State of Pernambuco, in which deformed and undisturbed samples of soil and saprolite were collected for chemical, physical, mineralogical and micromorphological analyses. The three profiles were classified as Cambissolo Háplico Tb Eutrófico léptico over Gneiss Schistadap (Zona da Mata), Planossolo Nátrico sálico típico over Gneiss Schistadap (Agreste) and Luvissolo Crômico Órtico típico over Gneiss Schistarap (Sertão), with all regoliths presenting shallow soil. Physical analyzes showed limitations regarding porosity in the profiles, with all of them presenting low porosity and sand and silt content greater than clay in most horizons. Routine chemistry showed high levels of all plant nutrients, with emphasis on the sodium content observed in P2, and the available phosphorus found in the saprolite of all profiles. The three profiles showed higher proportions of Si, Al, Fe, Ca, Na, Mg and K, consistent with the characteristic geochemical composition of the source rock (Gneiss), these elements were also identified via scanning electron microscopy. The applied weathering indices showed values that indicate moderate weathering in all profiles, not being sensitive in detecting the effect of the climatic gradient, with the highest values being found in the diagnostic horizons and decreasing in depth. Various associations of REE with phosphate minerals such as possibly monazite and/or xenothym were detected by study with energy dispersive X-ray spectroscopy. A negative correlation was identified between well crystallized iron oxides and light rare earth elements, as well as organic matter with these same elements, a positive correlation was also identified between light rare earth elements and available phosphorus. Based on the analyzes carried out, it is possible to infer that the high level of available phosphorus is correlated with REE, especially the light ones, which are associated with phosphate minerals such as monazite.

Ultramafic soils are formed from weathering rocks rich in ferromagnesian minerals and with a low silica concentration. These soils have high levels of magnesium (Mg), iron (Fe), manganese (Mn), and potentially toxic metals such as nickel (Ni), cobalt (Co), and chromium (Cr). Due to nutrient impoverishment, ultramafic soils are unsuitable for agriculture; however, some plants adapted to these soils, called hyperaccumulators, accumulate high Ni concentrations in their tissues. The agromining technique uses these plants to obtain biominerals by incinerating their aerial parts. An example of a Ni hyperaccumulator plant is the South African species Berkheya coddii, which has high biomass and a high Ni concentration in leaves. This study aimed to i) investigate the effects of citric acid application on Ni solubilization in ultramafic soil and its accumulation in B. coddii and ii) evaluate the biomass production and Ni accumulation in this species in response to applying mineral (NPK) and organic (bovine manure and sewage sludge biochar) fertilizers. The results showed that citric acid application affected the biogeochemical dynamics of the soil-plant system, increasing the metal bioavailability in the soil and the extraction, translocation, and accumulation of Co, Mn, and Fe by B. coddii. On the other hand, citric acid did not significantly increase the Ni content in the aerial part of the plants. Mineral fertilization and manure considerably increased plant biomass but negatively affected shoots' Ni content. Applying biochar did not affect the biomass production of the plants or the Ni content accumulated in the aerial part.

The onion (Allium cepa L.) is one of the most widely grown and consumed vegetables in the world and has great commercial value. Silicon is considered a beneficial element, providing plants with resistance, rigidity to plant cells, tolerance to water stress, protection against heavy metal toxicity and inducing resistance to insect pests and fungi. The soil is of essential importance for life support functions and the soil microbiota plays a fundamental role in carrying out these functions, so the use of silicate fertilizer has an impact on the soil's microbial community, improving its conditions and leading to higher crop yields. In this sense, microbiological indicators are used to monitor soil degradation and evaluate management strategies to guarantee agricultural productivity, especially in economically important regions such as the São Francisco Valley. Thus, it was hypothesized that silicon fertilization in onion cultivation increases soil microbial biomass and activity. The aim was to evaluate soil quality based on microbiological indicators under onion cultivation with silicon application in the São Francisco Valley at doses of 0 (control), 75, 125, 175 and 225 kg ha-1 , with four replicates. For this purpose, the carbon of the microbial biomass, the basal respiration of the soil, the microbial, metabolic and mineralization quotients were determined and the activity of the enzymes was quantified: alkaline phosphatase, arylsulfatase, β-glucosidase and glomalin. Fertilizing with silicon increased microbial biomass and soil microbial activity, with the highest values for biomass carbon being observed at doses of 75 and 125 kg ha-1 (345.60 and 327.22 mg kg-1 , respectively), due to the higher concentration of C in the soil. The application of silicate fertilizer led to an increase in basal soil respiration (C-CO2), with the highest C-CO2 values observed at a dose of 225 kg ha-1 (56.98 mg kg-1 ), due to the C/N ratio. Silicon had no influence on total organic carbon (TOC), microbial quotient (qMic), easily extractable glomalin and total glomalin. The application of silicate fertilizer led to an increase in the mineralization and metabolic quotients, with the highest qCO2 values being observed at a dose of 225 kg ha-1 (0.21 mg kg-1 ) and the highest qMin value being obtained at a dose of 225 kg ha-1 (0.92 mg kg-1 ). The application of silicate fertilizer led to an increase in the enzymatic activity of alkaline phosphatase, while arylsulphatase and β-glucosidase decreased as the doses increased. The highest doses (225 kg ha-1 ) were more efficient. Silicon acts on the soil microbiota, influencing microbiological attributes and as a mitigator of biotic and abiotic stresses in plants, promoting an improvement in onion crop productivity.

The Amazonian Dark Earth (ADE) are soils of anthropogenic origin that present high fertility and organic matter content, differently from the soils of the region, contributing to the increase of microbial activity. Thus, the present work aimed to evaluate microbial diversity, metabolic processes and biogeochemical transformations related to the maintenance of fertility and sustainability of ADE and its biotechnological potential through molecular and crop-dependent techniques. The soil of the ADE profile and the adjacent soil (ADJ) were collected in the Eastern Amazon region, in the municipality of Bragança, Pará State, to perform chemical, microbiological and grain size analyses. The prospection of ADE profile bacteria was performed by serial dilution method and, subsequently, the isolates were tested "in vitro'' for plant growth promoting mechanisms: Indole-Acetic Acid (IAA) production, siderophores, phosphate solubilization and biological nitrogen fixation (BNF). In addition, 52 isolates were selected for DNA extraction, amplification of the nifH and acdS genes, and sequencing of the 16S rRNA gene. Total soil DNA was extracted, quantified and sent for metagenome sequencing. The ADE soil was classified as dystrophic Gleysols A-Cg and chemical characterization revealed acidic pH in both the ADE profile and the adjacent soil (ADJ), increased nutrients at depth, low base saturation, and high aluminum saturation. The A horizon of the ADE soil had the highest levels of glomalin. Of the 466 isolates from the ADE soil profile, 84 solubilized phosphate, 113 produced IAA, and 13 produced siderophores. Of the 149 isolates selected for BNF, only 3 were negative. As for the presence of the nifH and acdS genes, of the 52 isolates, 23 and 12 were positive, respectively. Sequencing of the 16S rRNA gene revealed the predominance of the Bacillus and Pseudomonas genera among the samples in the ADE profile. Metagenomic analysis revealed the presence of Acidobacteria, Proteobacteria, Chloroflexi and Actinobacteria as the dominant phyla in the ADE and ADJ samples. As for the classes, Actinobacteria, Alphaproteobacteria, Deltaproteobacteria and Betaproteobacteria, were the most present and the orders Rhizobiales, Acidobacteriales, Ktedonobacterales, Streptomycetales and Burkholderiales stood out in all samples. A great diversity of bacterial families was observed, mainly, Acidobacteriaceae, Streptomycetaceae, Solibacteriaceae and Bradyrhizobiaceae. The predominant genera and species were Streptomyces, Bradyrhizobium, Candidatus Sulfopaludibacter, and Candidatus Sulfotelmatobacter; Acidobacteria bacterium, Chloroflexi bacterium, Candidatus Bathyarchaeota archeon, Terrabacteria group bacterium ANGP1, Actinobacteria bacterium, Alphaproteobacteria bacterium, Gammaproteobacteria bacterium, and Planctomycetes bacterium, respectively. As for the metabolic and functional profile of the samples, evidence was found of proteins and enzymes related to the glycolysis, pentose, Krebs cycle, electron transport chain, carbohydrate cycle, N, S cycle, methane, arsenic and mercury pathways. Overall, the results found in the present study revealed the high potential of microorganisms obtained in the TPA and their ability to perform important ecological functions ensuring the proper functioning of the ecosystem.

Ultramafic soils are anomalous environments in terms of heavy metal content (mainly Ni, Co, and Cr) and can generate economic returns through mineral extraction. However, conventional extraction techniques are responsible for strong environmental impacts. In this scenario, hyperaccumulator plants can remove high amounts of metals from enriched substrates in an economical, ecological, and profitable way through agromining. Although promising, this approach requires species prospecting, soil management strategies, and risk assessment to ensure environmental sustainability. Thus, this work aimed to develop a method to monitor Ni levels in plants by portable X-ray fluorescence (XRFp) and to evaluate the natural and induced accumulation of the metal in five tropical hyperaccumulators and their respective potentials for agromining in Brazil. Additionally, to investigate the environmental, ecological, and human health risks by exposure to soil particles and consumption of vegetables grown in this setting. To this end, 14 species with different Ni accumulation patterns were used for calibration using FRXp. Brazilian (Pfaffia sarcophylla, Lippia lupulina and Justicia lanstyakii), Mexican (Blepharidium guatemalense) and African (Berkheya coddii) species grown on ultramafic soils were evaluated for Ni contents and spatial distribution of metals in leaves by synchrotron light-based X-ray microfluorescence (μFRX-SR). Petrographic analyses were performed on the source materials and the ultramafic soils were characterized chemically, physically and mineralogically. The available, pseudo-total, total, sequential and bioaccessible Ni, Co and Cr contents were determined. The carcinogenic and non-carcinogenic risks to human health, the bacterial community of the soils, and the effect of citric acid doses on metal availability were also evaluated. Our results showed that calibration model for FRXp was efficient in predicting Ni in plants (R² = 0.94). Brazilian hyperaccumulators showed low potential for commercial agromining However, the high Ni accumulation of B. guatemalense and B. coddii (> 1.0 %) makes these species candidates for tropical agromining. Furthermore, the application of citric acid (40.0 mmol kg-1) to ultramafic soil increased by 25.0 % the foliar Ni accumulation by B. guatemalense and by 60.0 % the metal content in the bio-ore. The species evaluated showed a similar pattern of spatial distribution of metals, and preferential accumulation of Ni in the phloem and epidermis, suggesting defense mechanisms against herbivory. In the soil, the total metal contents (mg kg-1) for the districts of Niquelândia and Buenos Aires, respectively, were Co (373.5 and 349.2), Cr (1844.5 and 2485.5) and Ni (9597.5 and 1428.5). Environmental and human health risks were estimated and considered acceptable due to higher retention of metals in Fe oxides and in the residual fraction. However, high ecological risks were described for both soils and unacceptable cancer risk from consumption of vegetables grown in these environments. The highest metal tolerance was observed in the phyla Proteobacteria, Bacteroidota and Firmicutes. Therefore, our results indicate efficient Ni monitoring by FRXp and high potential for natural and induced Ni agromining in Brazil. Furthermore, management that intensifies erosion and mobility of metals and food crops on these soils should be avoided to ensure food security and environmental sustainability.

The soil is an open system formed by organic and inorganic constituents that can be evaluated by diffuse reflectance spectroscopy. Thus, the present study aimed at testing different combinations of preprocessing and calibration methods for the prediction of chemical elements (Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sb, V, Zn, Sc, La, Ce, Pr, Nd, Sm, Eu, Y, Gd, Tb, Dy, Er, Ho, Yb, Lu), group of elements (LREEs, HREEs, LREEs/HREEs, REEs), granulometric attributes, pH, cation exchange capacity and total organic carbon from the spectra obtained in the near-infrared region (NIR) as pedoindicator attributes. The soil samples were select to representa the geological and pedological diversity of the northeast Brazil. We hypothesized that (i) regarding the prediction of chemical elements in soils derived from different parent materials, the choice of the mathematical model is more important than the choice of pre-processes and (ii) under the same geological, pedological and climatic context, mathematical models of soils in the NIR range from other areas can be used for the prediction of chemical elements in areas where only spectral signatures exist. The states of PE, PB, and RN were select for this research because they represent the pedological and geological diversity of Brazil, which increases the applicability and scope of the results. All 13 soil orders in the Brazilian System of Soil Classification occur in the study area. Measurements in the NIR length range (1000-2500 nm) were performed in a Fourier transform FTIR/ NIR spectometer (Frontier/Perkin Elmer), coupled with a near Infrared reflectance accessory (NIRA). The Random Forest (RF) model had the best performance. Furthermore, it was also found that the choice of the model was more relevant than the choice of pre-processing. The better prediction of REEs compared toheavy metals can be observed by the higher values of the predicted residual deviation (RPD) and the ratio between the performance and the interquartile distance (RPIQ) and the lower values of the associated errors. Future studies must to further explore the combination of models with different computational natures rather than testing various preprocessing techniques with single models. The predicted values for geographic regions where only spectral signatures existed showed moderate spatial dependence, except for Pr, Sm, and Tb, which showed strong spatial dependence. This reinforces the quality of the predicted maps for REEs, which are essential for identifying areas susceptible to environmental impacts - an important step in establishing environmental policies for the protection of human health and the environment

The Brazilian semiarid is inserted in several environmental problems that impede the potential growth of agriculture with the presence of poorly developed soils of infertile nature or with accumulation of salts. Even with the adversities raised, techniques for improving soil quality and the applicability of saline water, frequent in these regions, have sharpened the search for management strategies, aiming at better coexistence and use of resources from this environment. In addition, soil fertility can be increased in an environmentally sustainable way with organic fertilization techniques based on plant and animal waste. The species Helianthus tuberosus L. is cultivated in the most diverse regions of the world and, due to its rusticity, it is able to coexist in adverse environments with problems of salinity, water deficit and low fertility. Given this context, the research aimed to evaluate the potential for cultivation of the species Helianthus tuberosus L. (cv. “Stampede”) in different soils under irrigation with increasing proportions of saline waste in a protected environment; and, under field conditions, evaluate its productive potential under different sources of fertilization. The research was carried out in two stages, the first being conducted in a protected environment for 70 days, in a randomized block design (DBC), in a 3 x 6 factorial arrangement, with the factors consisting of three different soils - S (S1 - Serra Talhada; S2 – São Bento do Una and S3 – Caruaru), through irrigation with six different proportions of saline waste and local supply water (A1 – 100% supply water; A2 – 95% supply water + 5% saline waste ; A3 – 90% supply water + 10% saline waste; A4 – 80% supply water + 20% saline waste; A5 – 60% supply water + 40% saline waste and A6 – 30% supply water + 70% saline waste), with four replications in blocks, totaling 72 experimental units. Biometric and physiological variables were measured at 15 and 35 days after application of saline treatments and, at the end of the experiment, biomass production, nutritional contents in plant tissues and soil analysis. The second experiment was conducted under field conditions, in an area belonging to the Instituto Agronômico de Pernambuco (IPA), in the municipality of Caruaru, for 120 days. A randomized block design (DBC) was adopted, with treatments consisting of a control (without fertilizer application) and four sources of fertilization (mineral fertilization with NPK; fertilization with goat manure; organic compost; mixture of goat manure + organic compost), in four repetitions, totaling 140 plants in the total area. Monthly biometric measurements were carried out on the plants and, at the end of the cycle, the productive potential of the crop was analyzed by means of biomass production, nutritional status of the plant, photosynthetic pigments, soluble solids content, enzymatic activity; as well as chemical analyzes of the soil. The increasing proportions of saline waste directly influenced the morphological and physiological variables of the plants, with significant decreases under the most saline waters, indicating the sensitivity of the plant to excess salts. The effects of salts on irrigation water varied according to the different soils used. Plants cultivated in Caruaru soil tolerated salinity up to irrigation water with 20% saline waste. There was a greater accumulation of Na⁺ and Cl^- in the aerial part of plants irrigated with waste from the desalination plant. The species Helianthus tuberosus L. showed positive cultivation potential in non-salinized soils and under irrigation with low proportions of saline waste in the irrigation water. Morphological characteristics and biomass production were positively influenced under NPK fertilization, composting and the combination of compost + goat manure. The nutritional status of the plant partitions was increased in all treatments with fertilization compared to the treatment without fertilization, with potassium (K) and calcium (Ca) having greater accumulation. Soil fertility was enhanced with fertilization and plant cultivation, favoring phosphorus (P) and calcium (Ca) levels, increasing CEC and soil pH. The total productive potential of the tubers was higher in the treatments with mineral fertilization and compost, but the other treatments with goat manure and the combination compost + goat manure also showed higher values than the treatment without fertilization.

The soils of the semi-arid region are going through a process of natural degradation, but enhanced by human action. However, it is difficult to measure/quantify this degradation, based on a standard quality index. With this, the objective was to generate a Soil Quality Index (IQS) when subjected to different forms of use, integrating physical, chemical and biological attributes in Cariri Paraíba, in Taperoá-PB. Four areas were chosen that were being subjected to different forms of use: irrigated tifton grass (CI), forage cactus (PA), rainfed buffel grass (CB) and riparian forest (MC). Nine composite soil samples were collected from each form of land use, in the surface layer (0-20 cm), to evaluate chemical, physical and biological attributes. The chemical attributes evaluated were: pH, EC, PST, Ca2+, Mg2+, K+, Na+, (H + Al), SB, T, V, Cu2+, Fe2+, Mn+, Zn+ and B. The physical attributes evaluated were: coarse sand (AreiaG), fine sand (AreiaF), silt, clay, soil density (Ds), particle density (Dp), clay dispersed in water (ADA), degree of flocculation (GF) , degree of dispersion (GD), aggregate stability index (IEA), aggregates larger than 2 mm (AGRI), total porosity (Pt), mean measured diameter (DMP), geometric mean diameter (DMG), macroaggregates (MacroA, mesoaggregates (MesoA) and microaggregates (MicroA).The biological attributes evaluated were: total organic carbon (TOC), soil microbial biomass carbon (C-BMS), soil microbial biomass nitrogen (NBMS), carbon/ microbial biomass nitrogen (C-BMS/N-BMS), soil basal respiration (RBS), metabolic quotient (qCO2) and microbial quotient (qMiC). The data were subjected to the Shapiro-Wilk normality test and homogeneity of variance tests with Levene's test. After a preliminary analysis, the need for parametric analysis such as ANOVA and Tukey test was noted. A principal component analysis (PC) was carried out and the IQS was established for all areas with different land uses, considering the chemical, physical and biological attributes separately, in addition to establishing the IQS considering all attributes together. A classification was also generated for the IQS, assigning interpretations as low, medium and high. The IQS was most influenced by physical attributes, especially those that are more directly impacted by chemical attributes, such as salinity indicators (EC, PST and Na+). Therefore, the IQS was more dependent on the structure and degree of dispersion of the soil. The areas occupied by buffel grass and cactus presented IQS equal to and greater than 0.9, respectively. The area irrigated with tifton grass presented the lowest IQS, suggesting that these areas in semi-arid soils are adequately monitored, mainly due to the chemical quality of the water used in irrigation, linked to good management of organic matter. In all areas, biological attributes had little influence on the IQS, suggesting that the use of organic matter is a mandatory condition for whatever land use in the semi-arid region. The joint assessment of chemical, physical and biological attributes better reflects the “status” of the soil and is more appropriate for establishing its quality index, suggesting that these attributes be interpreted in a contextualized way, for a more adequate assessment of land use. The IQS of all areas with their different uses was considered high, when the chemical, physical and biological attributes were jointly evaluated, suggesting that the uses are being adequate in the studied environment, as long as the organic matter management recommendations are observed, recommended to these semi-arid environments in a continuous and dynamic way.

Infrared reflectance spectroscopy has shown potential for use in environmental studies. It can assist in monitoring and preventing contamination in different environments. However, its application in mangroves is scarce, thus proving to be a viable alternative for monitoring these ecosystems vulnerable to environmental contamination. In this sense, this study aimed to evaluate the potential of near-infrared spectroscopy in predicting heavy metals in mangrove soils in the estuary of the Botafogo-PE River. For this, composite samples were collected in the 0-5 cm depth, obtaining 61 samples, in which spectral readings were taken in the near-infrared range (NIR, 1000-2500 nm). Pre-processing was applied to the data to improve the accuracy of the models, and partial least squares (PLS) regression was used to build the prediction models for the following attributes: clay content, MOS content, pH, Eh, Cr, Cu, Hg, Ni, Pb, and Zn concentrations. The performance of the models was evaluated using the root mean square error (RMSE), adjusted coefficient of determination (R²adj), bias, Ratio of Performance to InterQuartiledistance (RPIQ), and Lin's correlation coefficient of agreement (CCC) for the validation set. The best results were obtained after applying the following preprocessing: Savitzky-Golay (SG) and Multiplicative Scatter Correction (MSC). The predictive models that presented the best performances were: Cr (R2adj = 0.82; RMSE = 6.78; CCC = 0.85; bias = - 0.15; RPIQ - 1.4) when the SG preprocessing was used, and Pb (R2adj = 0.85; RMSE = 2.35; CCC = 0.85; bias = -0.3; RPIQ = 1.44) when the MSC was applied. The variables pH and Eh showed the lowest performances for both preprocessing. The results provide evidence that near infrared spectroscopy can be used efficiently to predict the studied metals, mainly Cr and Pb, which presented the best results, presenting itself as a technique to complement traditional analyses.

Rocks and sediments exposed on the earth's surface are subject to conditions that promote weathering reactions, among the factors that control these reactions, the climate is the main catalyst of the reactions, mainly through precipitation. The rock alteration has clays as one of its main products; clays are particles (< 2 μm) of minerals that play a fundamental role in soil dynamics, they present a wide variety of species that differ according to their formation environment. Arid and semiarid soils generally have clays with complex mineralogy, the mineral species vary from primary minerals inherited from the source material to secondary minerals formed during pedogenesis. The reactions formation and transformation of clay in soils is discussed in different environments, however few studies describe these processes and their resulting mineral phases in semi-arid climates. This work aimed to characterize the mineral phases of clays and identify their main formation processes in two Luvissols formed from the weathering of crystalline rocks (amphibolites) in the semi-arid region under two precipitation conditions (drier and wetter). Different x-ray diffraction techniques XRD were used (Modeling of oriented patterns, analysis of non-oriented patterns in the region of the 060 planes), thermogravimetric analyses, Fourier transform infrared spectroscopy (FTIR), and selective chemical extractions. The results showed the presence of mineral phases formed mainly from the weathering of hornblendes, biotites and feldspars; phyllosilicates are mainly composed of interstratified kaolinite-smectite phases in transformation, having a higher layer proportion of smectites in the drier environment and kaolinites in the wetter environment; both soils presented oxy-hydroxides phases composed of hematite and goethite, with higher Hm/Gt ratios in the wetter environment. The differences between the mineral phases of the two soils explain the variation of physical and morphological characteristics found in the Luvissols of the semiarid region.

The regolith, which encompasses soil and saprolite, plays an ecological role in the relationship between plant species, groundwater cycle and geochemical processes relevant to the ecosystem. CO2 emissions into the atmosphere are a matter of concern for society, and regolith is a recognized sink. The formation of carbonates “mineral carbonation” occurs naturally in regoliths through reaction of CO2 with mineral dissolution products, potentially acting on carbon sequestration. In the literature, the formation of carbonates by the weathering of basaltic rocks is well known. However, in this study, our hypothesis is: Regolith profiles derived from acidic metamorphic rocks located under a semiarid climate in the state of Pernambuco have geochemical, mineralogical and structural characteristics that favor the process of carbonate formation in the saprolite. The study focused on three equidistant regolith profiles along 900 meters in the municipality of Jataúba, inserted in the geomorphological domain of the Borborema Complex, state of Pernambuco. Soils and saprolites were classified, morphologically described, structurally evaluated and collected. In the deformed and undisturbed samples collected from autochthonous horizons, chemical and physical analyzes, mineralogical analyzes by X-ray diffractometry (XRD), geochemical analyzes by X-ray fluorescence (FRX) and micromorphological analyzes by scanning electron microscopy (SEM) associated with energy dispersive X-ray spectroscopy (EDS) were performed. Field tests showed a strong reaction of saprolite to HCl and electron micromorphology showed calcium precipitates around altered feldspars. The compact structures of the horizon overlying the saprolite and the virtually preserved rock underlying the saprolite must have favored the formation of carbonates by keeping the H2CO3 solution in contact with the altered minerals. In addition, the biotite and plagioclase-rich melanosomes inherited from the gneiss by the saprolite have mineralogical and geochemical characteristics similar to those observed in basic rock saprolites. We infer that the increase in the levels of Ca2+, Na+, Mg2+ and H2CO3 in the solution is favored by the regime of rainfall + evapotranspiration and that the origin of the CO2 necessary for the formation of carbonates in saprolites is atmospheric and by respiration of microorganisms. The present work serves as a reference for future studies to estimate the contribution of carbonate formation in saprolites from the northeastern semi-arid region to CO2 sequestration.

Ultramafic soils originate from the weathering of ultrabasic rocks, rich in mafic minerals and ferromagnesian silicate minerals. Due to the difficulty of developing agriculture in these areas, there is an opportunity to commercially phytomine ultramafic soils to produce a biomass that can generate a bio-ore, Hyperaccumulator plants have been used to this aim. However, nonaccumulating plant species with high biomass production can be chemically induced by chelating agents to mobilize metals from the soil to the shoot, a common practice in phytoextraction from contaminated soils, but not tested for phytomining yet. In this sense, the present study aimed to evaluate the effects of citric acid on the induced extraction of Ni, Cr and Co by maize plants (Zea mays) cultivated in an ultramafic soil and to determine the redistribution of these metals between soil fractions as a result of the application of the acid. Emphasis was given to the element Ni, due to the high commercial value of this metal and the possibility of its recycling from plant biomass. The experiment was carried out in a greenhouse with application of citric acid to the soil at concentrations of 0, 5, 10, 20 and 40 mmol kg-1 of soil, in three successive croppings. The results showed that the available concentrations of Ni, Cr and Co increased by the rates of citric acid after each of the croppings. The sequential extraction showed that the acid increased the percentages of Ni and Co in the exchangeable fraction of the soil. The chelator had no effect on the available concentrations of Cr, which was mainly retained in the residual fraction. The application of citric acid at doses of 20 and 40 mmol kg-1 of soil resulted in the highest concentrations of Ni in the aerial part of the plants, with no significant difference between these two rates. Therefore, 20 mmol kg-1 recommended to induce Ni phytoaccumulation. Despite the considerably high Ni concentrations in the shoots (500-600 mg kg-1), assisted phytomining using maize plants, for the soil and concentrations tested here, is not an alternative to the use of hyperaccumulators due to the low Ni shoot concentrations.

Mangroves act important role in environment because operate as mitigating place in case of environmental disasters such as storms or erosion. These ecosystems are an important spawning area and nursery for marine biota. Beyond that, acts as key role in carbon capture and have a wide microbial diversity. Despite that importance, mangroves ecosystems have been adversely affected by human activities, primarily the high load of organic and inorganic contaminants. These activities are responsible for changes in the physical-chemical, geochemical and biological parameters of this ecosystem. The soil samples used in this study (P1 and P2) were collected in the mangrove swamp of the Botafogo River estuary, located in Itamaracá, Pernambuco, Brazil. This estuary has the worst mercury contamination rates recorded on the entire Brazilian coast, this pollution was caused by improper waste disposal from an old chlorine-soda factory installed in the region, named Brazilian agrochemical (Agroquímica do Brasil). Soil sample collection were analyzed in laboratory and provided results of pH levels, Eh (redox potential), Soil Organic Matter (SOM) and Granulometry. The purpose of the research is to isolate and morphologically characterize bacteria from soils contaminated with mercury (Hg) collected in the Botafogo River estuary. And, in addition, to test the resistance of these Bacterial isolation to different concentrations of inorganic mercury (Hg) in culture media. For this, the process of isolation of bacteria was adopted in selective rich medium with Hg, in the form of HgCl2, in doses 0; 2.5; 5; 10; 50 and 100 mg L-1. Luria-Bertani broth was adopted in this study. As a result, a total of 115 isolation were obtained, which were submitted to morphological and molecular characterization and gram stain. Bacterial strain resistant to a concentration of 100 mg L-1 of iHg in solid medium (11 isolation) were submitted to minimal inhibitory concentrations (MICs) tests, resulting in MICs between 50 and 100 mg L-1. The strains that showed the highest MICs were isolated from the soil sample with the highest Hg concentrations. The isolation most resistant to iHg were identified based on the 16S rRNA region and showed greater similarity to the genus Enterococcus, Bacillus and Pseudomonas.

The adoption of technologies that use the process of biological nitrogen fixation (BNF) can contribute to
low carbon agriculture, by guaranteeing inputs of this nutrient with substitution or reduction of the use of inputs
dependent on fossil energy for its production. In this sense, consortia with nodulating legumes and inoculation
with plant growth-promoting bacteria (GPCP) are practices that have the potential to contribute N to cropping
systems, enabling productive and environmental gains. Based on this, the objective of this research was to evaluate the effect of adopting these two technologies on the development, productivity, N balance and income of sugarcane crops in two producing regions in Northeast Brazil. The effect of inoculation with different growth-promoting bacteria on the development and histological characteristics of the roots of sugarcane seedlings (variety RB92579); the effect of inoculation with different growth-promoting bacteria and intercropping with nodulating legumes on the N balance (fixed amounts versus exported amounts of N) on the development and agricultural and industrial productivity of sugarcane (variety RB92579); grain yield of legumes intercropped with sugarcane and to estimate the economic benefits of different cropping systems in two producing regions in Northeast Brazil. For this, three experiments were set up, one in a greenhouse and two experiments that were replicated in the field in two different locations, the Sugarcane Experimental Station of Carpina (EECAC), in the municipality of Carpina, PE, and another Usina Miriri, in the municipalityp of Rio Rinto, PB. In the first experiment, sugarcane was cultivated in
tubes containing an inert and sterile substrate, receiving inoculations with endophytic diazotrophic bacteria
previously isolated from sugarcane, under monoxenic conditions, or without inoculation with mineral nitrogen
fertilization or without inoculation and without fertilizing. The bacterial strains used were IPA CC23-
(Paenibacillus sp.), IPA CF62 (Paenibacillus sp.) and IPA CC44 (Burkholderia sp.). The treatments were
distributed in randomized blocks with 4 replications, being evaluated biometric and histological attributes of the
seedlings. Field experiments were carried out in a factorial arrangement using a randomized block design; in which the treatments corresponded to the intercropping of sugarcane with different grain-producing leguminous species (cowpea and peanut in both experiments, and also soybean, only in one of the experiments) and different N sources for the crop from sugarcane (inoculation with the diazotrophic bacteria strain IPA CF62, inoculation with Embrapa's mix of diazotrophic bacteria and mineral fertilizer). Control treatments without intercropped legumes (single cultivation) and control without application of N source in the sugarcane furrow were included. In these field experiments, legume symbiosis (natural nodulation and amount of fixed N), grain yield, N balance and legume economic yield were evaluated in different systems. Biometric attributes were also evaluated during the time of cultivation, contributions of FBN and the transfer of fixed N, biomass production, agricultural and industrial productivity of sugarcane, in addition to the economic return of the adopted managements. In tubes, it was observed that sugarcane seedlings that received nitrogen fertilization produced more biomass, followed by seedlings inoculated with the strains IPA CF62 and IPA CF44. Histological aspects such as root hair densities were influenced by the inoculation of IPA CF62 and IPA CF44 strains. The studied strains showed greater growth promotion in relation to the other treatments. In relation to legumes, cowpea presented a greater contribution of FBN, greater production of biomass and grains and, consequently, greater economic return. In sugarcane, intercropping with cowpea associated with inoculation with the IPACF62 strain showed higher economic returns. The use of the technologies studied is promising for a more sustainable cultivation of sugarcane.

Maize is the main cereal produced in Brazil and in the world, being widely used in human and animal food and in the production of biofuels. Biological nitrogen fixation (BNF) and the use of processes mediated by the endophytic communities of this grass are alternatives for the availability of nutrients and other mechanisms to promote plant growth, with the potential to promote higher yields and economy of inputs dependent on fossil energy. Due to its social and economic importance, there is a wide availability of maize genotypes, recommended for the different growing regions. The objective of this work was to estimate the BNF and the qualitative composition of the communities of endophytic bacteria of maize genotypes, identified as the most productive for the conditions of the Brazilian Northeast, cultivated in different edaphoclimatic conditions. Three field experiments were carried out in the municipalities of Araripina, Serra Talhada and Vitória de Santo Antão, in the state of Pernambuco, all without the use of bacterial inoculants. In the semiarid region, the genotypes BRS 4107, BRS 5026, BRS 4105, POTIGUAR, COPACABANA, BR 5036, BR 5037, MUCURIPE, IPR 164 and BR 2121 QPM were cultivated. In Zona da Mata, the genotypes were 1L1411, 1P2224, DKB 390 PRO 2, 1F640, DKB 310 PRO 2, CMS 36, SÃO JOÃO, BRS 3042, 1P2227 and 1M1804. Despite the difficulties in selecting reference plants to estimate BNF in grasses, significant differences were observed between the isotopic compositions of N in the maize leaves and the N in the soil available for the crop (estimated using two different approaches) in two experimental areas. This result demonstrates that the technique of natural abundance of 15N can indicate maize genotypes with the greatest potential to benefit from BNF, useful information in plant breeding programs for the crop. Thus, it was verified that different corn genotypes recommended for higher productivity for the Northeast region of Brazil absorb N fixed by diazotrophs naturally established in the rhizosphere or endophytically. The genotypes BR 5036 and BRS 4105, in the Semiarid region, and DKB 310 PRO2 and 1F640, in the Zona da Mata, presented the highest proportion of fixed N. However, the ability to accumulate fixed N of the genotypes tested in the semiarid region is strongly impacted by soil and climate conditions and water stress, which restricted BNF in Serra Talhada. The communities of endophytic bacteria of uninoculated corn plants harbor genera with reports of presenting mechanisms that promote plant growth, such as FBN, production of phytohormones, suppression of phytopathogens, tolerance to abiotic factors and solubilization of nutrients. The maize genotype has no significant influence on the composition of the endophytic microbiome, but the place of cultivation does. The roots have a greater diversity of endophytic bacteria, probably due to the compounds excreted by it. The genera of endophytic bacteria with the highest occurrence in corn roots and stalks are Leifsonia, Bacillus, Klebsiella and Streptomyces, followed by Bradyhizobium, Paenibacillus, Enterobacter and Sphingomonas, regardless of the plant genotype or the soil and climate conditions of the place of cultivation. Pseudomonas, Acinetobacter, Geobacillus, Enterococcus and Mycobacterium occurred in smaller amounts, always with greater relative abundance in the roots. The results of this work emphasize the importance of further studies on the communities of bacteria in association with corn, the processes mediated by them and their interactions with the plant genotype and cultivation conditions, which will be fundamental for the establishment of managements that include techniques biotechnological tools to increase and sustain this important crop.

With a global extension of 130 million hectares, Planosols have been recognized and studied around the world. In Brazil, more specifically in the northeastern semi-arid region, these soils have been the subject of large studies. Planosols are characterized by having a plain B horizon, a striking feature of these soils is the enrichment of clay in the subsurface horizons. Soil clays are represented by clay minerals which are abundant components in fractions < 2mm. They play a significant role in soil functioning, as they control geochemical and soil formation processes. In the northeastern semi-arid region, studies of clay genesis and interstratified phases in soils that allow for evidence of formation/transformation processes are incipient. Therefore, knowing the representativeness of Planosols formed on an expressive lithology in the semi-arid region of Brazil, the aim of this research was to advance in the understanding of the clays minerals genesis of these soils formed on a granitic/gnessic suite under a semi-arid climate. For this, the crystallochemical characterization of fractions 2-0.2mm and < 0.2mm was carried out based on XRD techniques, XRD modeling, FTIR, EDX, Mössbauer spectroscopy and thermal analysis. Two profiles were selected for the study in the municipality of Lagoa do Ouro, one located in the lowest part (P1) and the other in the highest part of the landscape (P2). The results showed that the climatic conditions associated with the drainage of the study site favored the formation of interstratified mineral phases, indicating an incipient weathering. The main route of formation of phyllosilicates end members in these soils goes through the following route: Micas (biotite and muscovite) – Interstratified (Ilite-Vermiculite, Ilite-Smectite, Kaolinite-Ilite, Kaolinite-Ilite) - end members: Ilite + Smectite + Kaolinite /Halloysite. The halloysite present is probably formed from the alteration of feldspars and the presence of gibbsite in both profiles seems to be formed by neoformation in microsites of greater drainage in the soil structure. Through this study, it was possible to detail the mineral phases present in Planosols formed on a granitic/gneissic suite, expanding the understanding of soil pedogenesis in a semi-arid environment, as well as deepening the knowledge of the diversity of minerals, which may support future fertility studies, management and use of these soils.

The consumption of food grown on soils contaminated with cadmium (Cd) is one of the main routes of exposure to the element. The use of amendments to decrease the metal availability in the soil and its uptake by crops is an alternative for reducing Cd in the human diet. In this study, we assessed the application of amorphous silica-derived fertilizer (ASF) to soil arti-ficially contaminated with 10 mg kg-1 of Cd. The work evaluated the ASF influence on the Si and Cd availability in the soil and the transfer of Si, Cd, and nutrients from the soil to cowpea (Vigna unguiculata, var Miranda IPA 207). The Cd concentration in the grains was determined to estimate the risk to human health regarding grains consumption. The greenhouse experiment consisted of six treatments: 5 doses of ASF (0, 225, 450, 900, and 1350 kg ha-1) applied to the soil plus an additional treatment with no soil pH correction and no ASF application. Our results showed that applying ASF increased the Si availability and decreased Cd available concentra-tion in the soil by 65%; consequently, Cd concentration in roots and shoots were decreased. The concentration of N, P, K, Ca, Mg, Fe, Mn, Cu, and Zn increased with the ASF doses, indicating an improvement in plant nutrition driven by the Si fertilizer. Soil cultivation de-creased the pH to 5.6, significantly increasing the availability of cadmium. ASF ameliorates Cd phytotoxicity due to the reduction of Cd accumulation in roots and shoots. The application of 1350 kg ha-1 of ASF to the soil reduced the concentration of Cd in the grains by 39%. However, even with such a reduction, the consumption of grains still poses risks to human health.

Nitrogen (N) is a limiting factor in sugarcane production and is mainly supplied by fertilizers. Fertilizer-N losses in the soil-plant-atmosphere system are high and management alternatives to minimize the environment impacts caused on production field are required, mainly in ratoon cycle, which represents more than 50% of the cultivated area in Brazil. Plant growth-promoting bacteria (PGPB) act in plant hormones production, nutrient solubilization and in process of biological nitrogen fixation (BNF). Molybdenum (Mo) addition enhances these bactereal mechanisms performed by the bacteria, further to act in plant N metabolism, through the assimilation of N and promoting plant growth. The contribution of PGPB in sugarcane varies with the genotype of the plant and bacterial strain. Analysis of plant proteome allows understanding the roles played by Mo and PGPB in sugarcane fertilized with N. The objective was to evaluate the development of two sugarcane varieties (RB867515 and RB92579) inoculated with PGPB UAGC 869 (Stenotrophomonas sp.) and fertilized with two doses of Mo (0 and 0.2 kg ha-1) and N (0 and 80 kg ha-1) at 100 and 340 days after harvest (DAH) of first ratoon cycle. Treatments with statistical effect on biomass production at 100 DAC, differential protein accumulation was evaluated by large-scale mass spectrometry (SHOTGUN). N and Mo increased height and shoot biomass production in both varieties. Inoculation with Stenotrophomonas sp. UACG 869 inhibited the positive effects of nutrients on the biomass production of RB867515. Proteome analysis was performed for N+Mo in RB92579 and for N+Bac in RB867515 due to effect of increasing and decreasing aeral biomass of the respective varieties. The combined application of N and Mo in RB92579 increased the amount of protein related to photosynthetic efficiency, production of plant hormones (auxins and abscisic acid), nitrogen assimilation proteins and stress control (biotic and abiotic), which results in greater shoot and root development in sugacane ratoon. For RB867515 the inoculation of the bacterium Stenotrophomonas sp. UAGC 869 in plants fertilized with N, it promoted greater spend of energy by respiration and inhibited proteins related to photosynthesis. The imbalance in the photosynthesis / respiration ratio resulted in a reduction of plant aerial part development. These results demonstrate the efficiency of Mo in nitrogen nutrition of sugarcane ratoon and the identify new mechanisms in the plant proteome regulated by it, which can be used as an alternative for sustainable management in the second cycle of sugarcane. It was also identified that the efficiency of the interaction between sugarcane and Stenotrophomonas sp. UAGC 869 depends on the variety.

TThe productive sustainability of sugarcane fields depends on adequate nutritional management of sugarcane. Among the nutrients, Nitrogen (N) is the second most absorbed and the one that most limits crop productivity. Leaching losses that occur in sugarcane fields reduce the availability of N for the crop. To meet the need for sugarcane, doses of up to 200 kg ha-1 of mineral N are applied to sugarcane fields, but the recovery of fertilizer N has been limited to 50%. Foliar fertilization can be an alternative to compose more efficient fertilization managements. Whereas, up to 70% of N in the form of N-urea can be recovered by sugarcane within 24 hours. The objective of this work is to evaluate the efficiency of foliar fertilization with N-urea solution in increasing the recovery of N-fertilizer and reducing its leaching losses during sugarcane development. Seven N application managements with doses of 60 kg ha-1, combining reduced fertilization via soil and supplementation on the leaf, plus an extra treatment with application of 120 kg ha-1N via soil, were tested and arranged in three blocks by chance. In the first seven months, N leaching was evaluated. At 162 Day After Planting (DAP), 194 DAP and 224 DAP, the fertilization efficiency, growth and accumulation of aboveground biomass in sugarcane were evaluated. Nitric-N had the greatest participation in the leached solution. The smallest concentrations of N in the leachate and the smallest losses of N by leaching were verified in managements with a dose reduction of 50% (30 kg ha-1) and 25% (45 kg ha-1). In these managements, the N-nitric had greater participation in the leached solution. Foliar fertilization optimized 15N-fertilizer uptake and increased N content and accumulation, biomass production, plant height, and number of internodes. The best responses were identified in the management with a 50% reduction of the dose in the soil with the complementation of two 15 kg ha-1 N applications. In this context, it is concluded that it is possible to reduce the input of N in the soil and complement it via the leaves without compromising the development and accumulation of biomass in the aboveground part of the sugarcane in the sugarcane plant cycle.

The increasing population increase has led conventional agriculture to the intensive use of conventional fertilizers in order to meet the growing demand for food supplements. The intensive use of these inputs, mainly phosphate, potassium and nitrogen fertilizers have caused serious environmental impacts. In this context, the use of organic inputs has become an alternative to the use of conventional fertilizers, as it reduces environmental impacts and preserves the physical, chemical and biological health of the soil. Therefore, this work aimed to evaluate the use of biological fertilizers based on rock powder rich in phosphorus and potassium and on the chemical properties in soil of the coastal plateau, as well as to analyze their effectiveness when associated with nitrogen-fixing bactéria of the genus Bradyrhizobium spp., in nutrition, biomass production and productivity in peanut culture. The experiments were carried out in a greenhouse at the agronomy department of the Federal Rural University of Pernambuco-UFRPE. The soil used in the experiment was an acidic soil with pH 6.5 of the coastal table from the Japungu plant, located in Paraíba, 644.5 km from Recife-PE. The experiment was carried out in a randomized block design in a double factorial arrangement (7 x 2) with five replications. The first level of factor were the sources of nutrition: Biofertilizer- BNPK 100% (10 t ha-1); Biofertilizer-BNPK 150% (15 t ha-1); Bioprotector-PNPK 100% (10 t ha-1); Bioprotector-PNPK 150% (15 t ha-1); conventional fertilizer - FNPK 100% (recommended dose); earthworm humus (12 t ha-1); and control (without fertilization). The second level of factor consisted in the use or not of nitrogen-fixing bacteria of the genus Bradyrhizobium spp. . Plant phytotechnical parameters and crop yield after 90 days of cultivation, chemical analyzes (N, P and K) of soil and plant were evaluated. Among the results found, the phytotechnical parameters of plant yield were influenced by fertilizers. Inoculation with Bradyrhizobium spp. reflected positively on plant fresh mass weight, root/plant dry mass ratio, number of pods, and grain mass. The biological fertilizer based on PK rock powder influenced the levels of phosphorus in the soil and in the plant and nitrogen in the soil, standing out the conventional fertilizer. The earthworm humus influenced the levels of potassium in the soil and in the plant. In view of the results obtained, the recommendation to use a biological fertilizer based on PK rock powder and earthworm compost is an alternative to conventional fertilizers for the cultivation of peanuts.

Brazil is experiencing the greatest success in the use of biological nitrogen fixation (FBN) in agricultural systems and, recently, has been positioning itself on the international scene with the description of new species of rhizobia. The diversity of combinations of types and soil cover makes the Zona da Mata of Pernambuco a region with great potential for studies of rhizobia ecology and for the search for new elite strains for biological nitrogen fixation (FBN). This project aims to estimate the occurrence and diversity of nodule bacteria from different species of the Crotalaria genus to make a collection available for obtaining inoculants for recommendation for green manure in soils in the Zona da Mata of Pernambuco. Initially, a representative sampling of the different edaphoclimatic conditions of the Zona-da-Mata de Pernambuco was carried out, encompassing soils of the main types and uses of soil in the region, at points defined according to the class requirements and soil cover. The soil classes were selected at the 1st categorical level, namely: ARGISSOLO, LATOSSOLO and GLEISSOLO, which together represent about 85% of the region's soils. Four types of vegetation cover, which are predominant in the Zona-da-Mata de Pernambuco, were defined: 1) cultivation with sugarcane; 2) capoeira; 3) other agricultural uses and 4) native vegetation (forest). The natural occurrence of populations of bacteria capable of forming nodules with three species of Crotalaria spp., As well as the development of plants grown in the collected soil samples were determined in experiments carried out in pots in a greenhouse. This experiment was also used as a bait plant test to isolate nodule bacteria from plants grown in soil samples representative of each situation. A collection of 505 nodule bacteria was obtained, which was characterized phenotypically in YMA culture medium. In isolates representative of the phenotypic groups used, an initial genetic profile of the populations naturally established in the studied soils was traced, through the evaluation of the genetic variability of the isolates using the techniques of BOX-PCR and Restriction Analysis of Amplified Ribosomal DNA (ARDRA). The joint analysis of the restriction profiles of the 16S rRNA, obtained from the endonucleases: Alu I, Xba I, Apa I, Xho I, Rsa I, Hae III and Nde I allowed the formation of groups of isolates with similarity, and according to with the distribution of the strains, it consisted of the separation of the isolates in the soil classes. This grouping points to genetic variability of the isolates and indicates a possible existence of taxonomic, among the isolates obtained, not yet known in the literature.

The Ipojuca River is the third most polluted river system in Brazil. High concentrations and fluxes of metals in sediments indicate the contamination pattern, compared with values from catchments impacted by mining. Recent hydrological and morphological changes in the estuarine-marine zone increased the susceptibility of fine particle and metal sedimentation in these environments. It is assumed here that other elements may be transferred, such as radionuclides, and that the identification of sources and controlling soil erosion and sediment transport can reduce the distribution of contaminants to the outlet and the local coastal environment. Accordingly, the objectives of this study were (1) to evaluate the natural contents in soils and the distribution of Th in suspended (SS) and bed (BS) sediments, (2) to evaluate the patterns of delivery of sediments based on the combination of different classifications of potential sources of the fingerprinting method and (3) to evaluate the dynamics of delivery of different sediment sources from the semiarid portion of the Ipojuca River. (1) The mean Th concentration in soils was 28.6 mg kg-1. The estimated quality reference values were at 21 mg kg-1 and 86.3 Bq kg-1. The Th concentration in suspended and bed sediments ranged from 2.8 to 32.9 mg kg-1. The suspended sediments transported 3.42 t year-1 of Th, equivalent to more than 99% of the flux of this element. In the downstream cross section, suspended sediment samples exhibited Th concentrations similar to those observed in rivers impacted by mining activities. However, there was no evidence of anthropogenic impacts on Th concentrations. The flux of sediments from the study area to the ocean is mainly triggered by soil erosion processes in the mid-lower course region. (2) The downstream region (SS = 80.5% and BS = 86.7%), the Oxisols (SS = 65% and BS = 30.8%) and sugarcane cultivation (SS = 62% and BS = 63.6%) were the dominant sediment sources. Combined, the Oxisols and sugarcane areas controlled about 63.5% of the SS and 47.2% of the BS transported, i.e., less than 8% or approximately 280 km² of the catchment. Approaches combining potential sources, based on robust discriminations, tend to provide greater detail of areas under dominant erosion and reduce the scale of containment of these processes. (3) The semiarid lower catchment presented significantly higher contributions than the other regional sources (middle and upper), approximately 69% and 56% of the SS and BS, respectively. There was no dominant source of land use. The Caatinga (SS = 49%; BS = 47%) expressed a mild superiority in relation to the channel bank (SS = 35%; BS = 39%). Therefore, the recovery and conservation of vegetation in the Caatinga and the stabilization of channel banks, especially in the lower stretch, are fundamental for controlling the transport of river sediments in the outlet of this semi-arid catchment. More studies are needed to better assess the conservative patterns of color parameters in semiarid environments. Here, we provide some of the first information on sediment contributions from the main land uses and land cover in the semiarid region of northeastern Brazil.

Biological nitrogen fixation (FBN) is the main input process for this nutrient in natural
ecosystems and in low-input agriculture. Furthermore, the introduction of leguminous
trees inoculated with diazotrophic bacteria can be a strategy for nitrogen acquisition to
recover degraded areas. jurema negra is a legume that occurs widely in several
fragments of caatinga, mainly in areas undergoing regeneration of native vegetation.
This species is capable of forming nodules and acquiring considerable proportions of
its nitrogenous nutrition through symbiosis with rhizobia. However, there is still little
information about the specifics of symbiosis. The objective of this work was to evaluate
the occurrence, characteristics and diversity of microsymbionts of black jurema
naturally established in soils in the semiarid region of Pernambuco. In order to carry
out a representative sampling of the different edaphoclimatic conditions, points were
selected in areas with dense caatinga coverage (with little anthropogenic interference)
and with the main classes of soils occurring in the biome: Argisol, Litholic Neosol,
Quartzarenic Neosol, Regolithic Neosol, Latosol, Luvissol and Planosol. To access the
rhizobian community of the soils, an experiment was carried out in a greenhouse using
black jurema as a bait plant. From the nodules collected in the bait-plant experiment,
391 isolates were obtained, most of them fast growing, with metabolism that acidifies
the culture medium and producing a lot of mucus. As a criterion for authenticating the
rhizobia status of the isolates, the ability to fix nitrogen and form nodules was evaluated
by means of the simultaneous amplification of the symbiotic genes nifH and nodC, and
250 positive isolates were selected by the Duplex-PCR method. The genetic diversity
of the isolates was evaluated by Restriction Analysis of Amplified Ribosomal DNA
(ARDRA) which allowed the formation of two groups, within which 29 subgroups were
formed at 75% similarity. From this grouping, 48 isolates were selected for evaluation
of the genetic profile through BOX PCR and sequencing of 16S rRNA and gyrB genes.
Analyzing the tree based on the 19 isolates with good quality 16S gene sequence, it
was found that the 19 isolates belong to the class of betaproteobacteria belonging to
the genus Paraburkholderia.

The growth of the world population makes the demands for resources essential for human survival to grow, the main one being the production of food, which impacts the soil and watercourses, among them, salinization. Salinization progressively reduces crop yields, especially in arid and semi-arid regions. Thus, the process of salinization of the soil and water sources, reveals itself as one of the main problems of environmental degradation in the semiarid region, limiting agricultural production. The use of salinity-tolerant species has been a valid strategy, recommended to promote the use of lower quality waters and in marginal areas. The research aimed to evaluate the potential for cultivation of Salicornia neei Lag. under irrigation with saline waste water and in soils affected by salts. The experiment was carried out in two stages, the first was carried out in a protected environment, like a greenhouse for 180 days, cultivating Salicornia neei in four different soils (S1 – Haplic Planosol; S2 – Haplic Cambisol; S3 - Fluvic Neosol and S4 - Fluvic Neosol), irrigated with 6 proportions of saline waste and drinking water (A1 - 100% potable water (control); A2 – 15% saline waste + 85% potable water; A3 – 30% saline waste + 70% potable water; A4 – 50% saline waste + 50% potable water; A5 - 70% saline waste + 30% potable water and A6 - 100% saline water), perfoemed in a blocks randomized, with four repetitions. In the second experiment, the plants were cultivated in open field, in saline soil, in the District of Maniçoba, municipality of Juazeiro, Stat Bahia, Brazil. The interaction between the sources of soil × water variation had a significant effect on biometric variables, gas exchange, photosynthetic pigments, soluble and exchangeable ions soil, and on the levels of elements in plants. Thirty isolates were obtained, selected by the presence of microaerophilic film, all with the capacity to produce biofilm, 21 isolates produced indoleacetic acid, 25 isolates were positive for the presence of the nifH gene and none of the isolates were able to solubilize calcium phosphate. Molecular fingerprint analysis includes 17 unique profiles in the collection choose from. The Amplified Ribosomal DNA Restriction (ARDRA) analysis of the single profiles allowed the formation of three large groups with 65% similarity. Seven profiles were selected for sequencing and after analysis it was found similarity with bacteria of the genus Pseudomonas, and Enterobacter. Biomass production and plant gas exchange are reduced with the increase in saline waste in irrigation water. Salt stress promotes an increase in Na + content of root dry matter at the expense of other cations. The microorganisms associated with salicornia are slow-growing and predominantly Pseudomonas and Enterobacter.

The improper disposal of mining waste is a problem worldwide. Slag containing heavy metals can pollute soil and water and contaminate animals and humans. The bahian city of Santo Amaro had a lead smelter that, for years, polluted its territory with the smoke from the chimneys and the slag improperly deposited throughout the city. In order to understand the dynamics of stabilized metals in soils conditioned with biochar, the present work aimed to evaluate the effects of applying biochar to a soil polluted by multiple metals on the bioaccessibility, availability and absorption of As, Cd, Pb and Zn by plants and on the phytoattenuation process, aiming to indicate an economically and environmentally sustainable way for remediation of contaminated soils. For this, an experiment was carried out in a greenhouse with increasing doses of vermin (equivalent to 0, 5, 10, 20 and 30 t ha-1) applied to polluted soil in the municipality of Santo Amaro-Ba and cultivated with corn. After cultivation, the levels of metals in the roots and shoots, nutrients in the shoots, the fractionation of metals in the soil and bioaccessibility tests were determined. In addition to the evaluation of physiological parameters (chlorophyll fluorescence, gas exchange and chlorophyll contents). The results showed that biochar can be indicated as a ameliorating for heavy metals in phytoattenuation or phytostabilization programs in the Santo Amaro contaminated soil, since it promoted a decrease in the mobility and availability of metals in the soil, with an improvement in the production of dry matter and photosynthetic attributes of corn plants.

The Northeastern region of Brazil accounts for 27% of the national fruit production, especially among vines (Vitis spp.), Whose production management is based on the intensive use of fertilizers and agricultural pesticides. Not only cause losses of production due to nutritional imbalances, but also environmental problems such as contamination of the soil by heavy metals and leaching of phosphorus to water bodies. Thus, the objective of the present work was to evaluate the impacts of the intensive use of phosphate fertilizers and their relationship with microbiological attributes of the soil under vines in the São Francisco Valley. The study areas are located in six grape production farms in the irrigated perimeter Senador Nilo Coelho, Petrolina, PE. In each area, three collection points were randomly chosen, where at each point, rhizospheric (SR) and non-rhizospheric (SNR) soil were removed, which were characterized both physically and chemically. The environmental contents of heavy metals were obtained, aiming to compare them with the Quality Reference Values (VRQ) established for Pernambuco. The dynamics, availability and different forms of P in the soil were evaluated using the sequential method of fractionation and the microbiological attributes: P of the microbial biomass, acid and alkaline phosphatase activity, as well as the glomalin content easily extractable from the soil, were determined according to specific methodologies. The management adopted by grapevine farms resulted in a change in soil fertility in relation to fallow areas, with a significant increase in soil organic matter, Ca, Mg and K levels, besides raising P levels to values higher than critical ground level. The heavy metals contents were similar between the cultivated areas and their respective fallow areas, indicating that these values are obtained from the weathering of the source material and the interaction of these elements and the soil. However, the Cu and Zn contents presented higher values than the VRQ, being this behavior attributed to anthropic interference. Excessive application of phosphate fertilizers contributed to a higher P uptake in soils under vines cultivation. It was observed that, in general, inorganic fractions exceeded the organic fractions of P, with the highest soil P contents found mainly in the fraction not labile, and in the labile fraction. It was observed that the availability of P, where Ca concentration and pH are high, negatively influenced the microbial P contents in the studied areas. The activity of the acid and alkaline phosphatases provided a rapid response to the addition of phosphate fertilizers in the environment, presenting great potential of use in the evaluation of soil quality. In addition, the high concentration of phosphorus in the studied areas significantly influenced the levels of glomalin in the soil. These new indexes can be used to establish a tool for soil quality assessment, contributing to a better evaluation of the impacts of P fertilization on soil microbiological attributes of the semi-arid region of Brazil

The Luvisols are considered as a grouping of soils with textural B, clay fraction of high-activity clays, high base status. They are soils with evolution according to the performance of the bissiallitization process combined with the production of iron oxides and the mobilization of clay from the superficial horizon, with accumulations in subsurface horizons. Studies in Luvisols have indicated the formation of clay in situ (argilation) as the main process of formation of Bt, however other processes such as argiluviation and lithologic discontinuity may be of comparable or greater importance in the creation of textural contrast, which characterizes this grouping of solos. In the semi-arid region of Pernambuco, bissiallitization becomes the predominant weathering path, with predominance of clay minerals 2: 1 (smectite and illite), 1: 1 (kaolinite), with illite interstratified with smectites. Fersiallitization and rubification were described as the most outstanding pedogenetic processes. Thus, this study sought to understand the genesis of clay minerals and texture contrast of Luvisols of the semi-arid region of Pernambuco (Brazil), evaluating the morphology, mineralogy and micromorphology along a transect in the semi-arid formed from the amphibolite alteration, as well as classify soils according to the Brazilian Soil Classification System (SiBCS) and WRB / FAO. The following characteristics were considered: being inserted in the semi-arid Pernambucano, native or secondary vegetation, without any kind of influence or anthropic action, mafic metamorphic crystalline basement (particularly amphibolites). The micromorphological analysis of the thin sections indicated no pedofeatures of clay illuviation thus the formation of clay in situ (argilation) responsible for the texture contrast in these profiles. Profile 1 located in Itacuruba (PE) was classified as Luvissolo Chromic Ortic vertissolic solodic saline (WRB- Chromic Vertic Luvisol (hypereutric, protosalic, sodic)), profile 2 as Luvissolo Chromic Ortic vertissolic (Chromic Vertic Luvisol (hypereutric)) and profile 3 as Luvissolo Chromic Ortic typical (Chromic Luvisol (hypereutric)). Profile 1 did not fit into a class cataloged in SiBCS, constituting a new class of Luvissolo.

Sorghum and Caupi are plants moderately tolerant to salinity with physiological and morphological mechanisms that enable their cultivation in soils affected by salt. Studies on such tolerance mechanisms allow a better understanding of adaptive responses of plants and therefore provide information that may be useful in the development of technological responses to the problem of salinity, whether these responses are genetic or in farm management. In the present study, two approaches were taken in the evaluation of plants: photosynthesis and water relations, both of which were based on a randomized block design consisting of 7 treatments (concentrations of 0.10, 20, 40, 60, 80 and 100 mmol L-1 of NaCl in daily irrigation water) and five replications, these approaches have being presented in two chapters. Therefore, sowing of cowpea and sorghum was carried out in buckets of 10L filled withFulvisol. After 15 days of sowing the treatment of increasing NaCl concentration in the irrigation water began, the experiment lasted 55 days for sorghum plants and days for cowpea plants. Soil throughout the evaluation period was maintained at 65% of field capacity in pot. In the first chapter of this work, with the objective of evaluating the water relations of the species and comparing methods for the determination of the osmotic potential, data were collected using the Scholander chamber (water potential and osmotic bypressure-volume curve); And using the osmometer, (reading of the concentration of the sap). The information obtained from the data confirmed the condition of more stress in the irrigated plants with higher concentrations of NaCl and showed variation in the sensitivity of the different methods to estimate the osmotic potential. In the second chapter, the aim of this study was to evaluate the effect of salinity on foliar gas exchange and on the A.M. using IRGA equipment (IRGA Licor-6400) at two moments of the experiment, before the start of saline treatment, 15 daysof sowing in both cultures, and after saline treatment, 40 days of sowing in sorghum and 48 days of sowing in cowpea. There was a reduction of the liquid photosynthesis (A), stomatal conductance (gs) and transpiration (E) in both cultures, indicating that the reduction of gs resulted in a lower water loss per E, but this had a cost in Reduction of A. The data on the physiological behavior of the species on capacity of capture light energy were studied based on assessments of the concentrations of photosynthetic pigments (chlorophyll a and b) and measurements of chlorophyll fluorescence using FluorPen equipment. The results showed that at 40 days there was a decrease in the pigment contents, but the efficiency of photosystem II was little affected in the sorghum. In cowpea at 48 days, reduction in pigment contents and reduction of the efficiency of photosystem II were observed.

In agricultural works containing water erosion, such as agricultural terraces, the flow velocity is calculated for both sandy texture soils and clayey soils only by methodologies developed for sandy soils, such as the Manning equation, which has been underestimated the flow velocity. The objective of this study was to validate the Mirtskhoulava (1966b) critical velocity equation for the condition of concentrated runoff in preformed erosion channels over a clayey textured horizon and to obtain soil cohesion by direct shear; it was also evaluated the shear strength of the soil by means of the shear envelopes in samples of a Bt horizon under field moisture and saturated using multivariate statistical techniques. The tests were performed in 16 preformed channels on the Bt horizon of the Ultisol with high clay content and 5 flow levels were applied. The following analyzes and determinations were carried out: soil granulometry, soil and particle density, soil detachment rate, soil erodibility, soil loss, soil roughness, flow shear stress, direct shear tests and permissible velocity. For the direct shear tests, 32 samples with a preserved structure were obtained to obtain the cohesion parameters and internal friction angle in a direct shear apparatus with a constant displacement velocity of 0.125 mm min-1. The shear stress generated by the applied flux (35-78 Pa) was not sufficient to reach the critical shear stress of the soil (103,60 Pa) in the channels and to initiate the erosive process in the channels. The Manning equation proved to be inefficient to estimate the permissible velocity when compared to the Mirtskhoulava equation, while the presence of parameters related to the cohesive characteristics of the soil in the Mirtskhoulava equation provided greater accuracy in the allowable velocity estimates. The shear stresses were higher for the field moisture condition, whereas for the saturated condition the opposite was verified. From the use of the multivariate, it was possible to detect the importance of the silt fraction in the shear of the samples under saturation condition.

Arid and semi-arid environments may present salty soils, which hamper plant growth, being removed from productive process constituting degradation cores. Under these conditions, glycophyte plants can’t growth because high levels of salts hinder their metabolism, however, for halophytes this is favorable environment and these plants may represent a key to soil reclamation, extracting salts in the vegetable material produced by phytoremediation technique. The study was conducted in a saline sodic INCEPTISOL from the Cachoeira II Irrigation Perimeter, Serra Talhada (PE), with the objective of evaluating changes in soil physical and chemical properties when under cultivation with the halophyte Atriplex nummularia Lindl, compared with chemical correction with gypsum, and plant growth and production monitoring under two spacing in the pruning management every six months. Samples were taken every six months, with four soil samples (0, 6, 12 and 18 months) and three cuts in the plant 50 cm from the ground surface (6, 12 and 18 months) measuring the material produced at each pruning.The experimental design was randomized blocks, four treatments were evaluated: control (no soil management), chemical correction with gypsum (no crop) and two Atriplex nummularia cultivation, one at 1 x 1 m spacing and other at 2 x 2 m spacing, with four replications. The results of soil chemical and physical analysis revealed the contribution of gypsum application and especially the cultivation of atriplex plants in reducing the problems of salinity-sodicity and improving soil physical properties. The biometric analysis and plant tissue showed the Atriplex nummularia potential for phytoremediation, with emphasis on the 1 x 1 m spacing which presented as the best recommendation of cultivation with frequent pruning due to higher plant material yield and extraction of salt per planted area.

The soil organic matter (SOM) comprises the plant residues in various stages of decomposition, microbial biomass, roots and more stable fractions, the so-called humus. The SOM regulates several chemical, biological and physical processes in soil and it is considered a key indicator of soil quality. The replacement of natural vegetation by crops often results in changes in both the quantity and the quality of SOM. The magnitude of these changes varies with soil properties, climate, crops and soil management. Some parameters such as phosphorus and soil organic carbon are not always sensitive to soil changes. Therefore the distribution of P and C fractions are used to better assess the SOM quality. The work aimed to evaluate the changes in chemical characteristics of SOM fractions such as microbial biomass, as well as in P and c organic fractions of a Humic Oxisol under different uses in Pernambuco, Brazil. Soil samples were collected from five different environments (native forest, scrub submitted to sporadic fires, a 30-year pasture use, pasture for 25 years and annual crops) at four depths (0.0-2.5; 2.5-5.0, 5.0-7.5 and 7.5-10.0 cm). The pasture systems for 25 years and annual crops caused negative impacts on most of the parameters. The effect of fire on soil under secondary forest resulted in increased levels of Ca2+ and Mg2+ and decreases in the contents of labile fractions of organic carbon, especially in the superficial layer (0.0-2.5 cm). About humic substances, there was a predominance of C in the humin fraction, followed by fulvic and humic acids in all the soils. Most of the labile and moderately labile P was found in organic forms. It summed up 64 and 88% of total P fractions, being the greatest percentage observed for the soil covered with pasture for 30 years.

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