Banca de DEFESA: CAIO NUNES GONÇALVES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CAIO NUNES GONÇALVES
DATE: 28/02/2025
TIME: 08:00
LOCAL: UFRPE
TITLE:

Sewage sludge and sewage sludge biochar: effects on soil quality and early sugarcane development

KEY WORDS:

Organic matter. Plant nutrition. Thermal processing. Organic waste. Sandy soil.

PAGES: 96
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Manejo e Conservação do Solo
SUMMARY:

The increase in daily waste generation due to population growth has contributed to pressure on environmental resources. As a result, numerous degradation processes occur in an accentuated manner, contributing to considerable decreases in the organic matter content of soils. In addition, sugarcane cultivation has been associated with a sharp increase in these processes, especially in sandy soils, requiring the adoption of strategies to mitigate these harmful effects, such as the addition of organic waste. Sewage sludge, rich in nutrients, appears to be a promising option in agriculture, but caution is required due to the risk of contamination. In this regard, thermal processing of sludge constitutes an interesting strategy, given the great potential of biochar. Thus, 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 at the Federal Rural University of Pernambuco, 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 a control treatment). Soil samples were collected at 7, 15, 30, 60 and 120 days to evaluate microbiological parameters (Cmic, C-CO2, qCO2 and qMic), NH4+, NO3- and available P. In the final evaluation, the total organic carbon (TOC), particulate organic carbon (PMOC), TOC and PMOC stocks were evaluated, the diagnostic leaf was collected for nutritional evaluation and the plant was collected to estimate dry matter production. The initial development of sugarcane was evaluated by biometric analyses, with four measurements performed every 30 days after planting. The results demonstrated that the isolated application of sewage sludge (L40) demonstrated more satisfactory results, with 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 a greater microbial efficiency in the use of C from this organic source and at this applied dose. The greatest effects on NH4+ and NO3- contents were noted 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 contents, 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 showed the highest levels of TOC (14.72 g kg-1) and TOC stock (45.32 ton ha-1) compared to the others, except when compared to L40. In contrast, B20 showed the lowest value for CMOP and CMOP stock, approximately 41.52% and 34.66% lower than the control, respectively, which demonstrates the great stability of the biochar used. For sugarcane nutrition, there was a limitation in plant nutrition, 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 higher than 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. Thus, it can be stated that the applied dose of sludge and its biochar can influence the chemical and microbiological characteristics of the soil, with emphasis on L40, which enabled positive results in most of the parameters evaluated.

COMMITTEE MEMBERS:
Presidente - ADEMIR DE OLIVEIRA FERREIRA
Interno - ***.952.028-** - FELIPE JOSÉ CURY FRACETTO - USP
Externo à Instituição - RENATO LEMOS DOS SANTOS - IFPE