CHANGES IN SOIL AGGREGATE STABILITY AND CARBON SEQUESTRATION MEDIATED BY LAND USE PRACTICES IN A DEGRADED DRY SAVANNA ALFISOL

Abstract

Effects of land use practices on aggregate stability and fractions of soil organic carbon were investigated using the physical fractionation procedure.  Soils were sampled at three depths (0-5; 5-15 and 15-25cm) under arable cropping, native vegetation and forest. These soils were separated into aggregates to calculate mean weight diameter (MWD) and aggregate associated carbon. Results showed that MWD increased in soils under forest by 61.4% relative to the soils under arable cropping practice. The macroaggregate fraction in the forested soils was 76.2% more than those soils under arable cropping. Chemically protected carbon was higher by 39% in soil under arable cropping compared to forested soils.  Forest plantations therefore, may have potential to increase the structural stability of soils and their resistance to soil erosion. Arable cropping seems to favor increasing carbon sequestration relative to native vegetation and Eucalyptus forested soils.