Banca de DEFESA: VITORIA MARIA VIEIRA BRITO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : VITORIA MARIA VIEIRA BRITO
DATE: 30/04/2024
TIME: 14:00
LOCAL: Google Meet
TITLE:

Carbon stocks and soil attributes in Caatinga areas issued for different uses

KEY WORDS:

Carbon stock. Soil management. Revegetation. Degraded area.

PAGES: 70
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Química do Solo
SUMMARY:

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.

COMMITTEE MEMBERS:
Presidente - MARIA BETANIA GALVAO DOS SANTOS FREIRE
Interno - JEAN CHEYSON BARROS DOS SANTOS
Externo à Instituição - ALEXANDRE TAVARES DA ROCHA