Aggregate stability and carbon stocks in Forest conversion to different cropping systems in Southern Amazonas, Brazil

Abstract

The process of converting natural ecosystems in cultivated areas, as well as use and land management systems have provided changes in aggregate stability and soil carbon stocks levels. The objective of this work was to evaluate the stability of aggregates and carbon stock in areas under forest conversion to different cropping systems, using statistical tools. Grids were established according to the culture dimensions, samples were taken at the crossing points of the grids at depths 0.00–0.05; 0.05–0.10; and 0.10–0.20 m, with 80 sampling points in each area, totaling 240 per area. At each sampling point, samples were collected with a preserved structure in the shape of a clod to determine the physical and chemical attributes, with a total of 960 samples in the four areas evaluated. The conversion process influenced soil aggregation, as measured by increased clay fraction dispersion and decreased WAD, GAD and aggregate classes >2.00 mm; The attributes were shown at the limit of the degree of spatial dependence, varying from moderate to strong; In the multivariate analysis, the forest and cupuaçu areas presented similar behavior, with values of OC, CS, silt, clay and classes of aggregates 2–1 mm, <1mm and ASI, above average.

Keywords

• natural ecosystems
• soil aggregation
• use and management systems