Aggregate stability and carbon distribution in Oxisol under no-tillage system in Uberaba, Minas Gerais State, Brazil

Abstract

The use of no-tillage system (SNT) with cover plants improves soil aggregation. The aim of this study was to evaluate the stability of aggregates in water and carbon distribution in different aggregates class in Oxisol in no-tillage system, Uberaba, MG, Brazil. It was evaluated two areas in SNT: crop of corn + brachiaria and corn + crotalaria. An area adjacent to the savanna was taken as a condition of the original soil. It was collected samples of soil deformability 0-5 and 5-10 cm, soil depths which was evaluated the stability of aggregates stable in water, by means of indices of aggregation: mean weight diameter (MWD) and geometric mean diameter (GMD). It was also evaluated the distribution of the mass of aggregates and carbon per sieve class. It was found that, regardless of depth, the area of savanna showed higher values for DMP, DMG and carbon. Among the cultivated areas, the system of crop corn + brachiaria showed higher values of DMP and carbon of aggregates in detriment of the area corn + crotalaria. These results indicate that the crop in SNT of corn + brachiaria increases soil aggregation and carbon aggregates when compared to the system of corn + crotalaria.