Organic carbon and aggregate stability of a Red Latossol under different managements

The objective of this work was to verify the influence of different managements on organic carbon and on aggregate stability of a Red Latossol (Typic Haplorthox). The following treatments were appraised: PDs no tillage for four years with successions corn (silage)/soybean; PDg - no tillage for four years with the successions corn/corn/corn/soybean; PDtf - three years with tifton (hay) and soybean in the fourth year; SC - conventional cultivation with soybean in the last four years; and MN - native forest. The aggregate stability was expressed by the indexes: mean weight diameter, mean geometric diameter, percentage of stable aggregates > 2.0 mm, and stable aggregates index. The aggregate stability in all the treatments decreased with depth. Indexes in cultivated treatments reduced in relation to native forest ones. The conventional system presented the worse indexes. Perennial grass tifton was the best treatment to recover aggregate stability. Significant positive correlations were obtained between total organic carbon and the studied aggregate stability indexes.