Physical quality of Haplorthox in a crop-livestock integration system after soybean cropping and palisade grass grazing

Abstract:

The objective of this work was to evaluate the effect of grazing height of palisade grass (Urochloa brizantha) on total organic carbon and on the physical quality of a Haplorthox (Rhodic Ferralsol), after soybean cropping and grazing periods on palisade grass, in a integrated crop-livestock system (ICL). A randomized complete block design with four treatments (grazing heights at 0.10, 0.20, 0.30, and 0.40 m) and three replicates was used, in the fourth and fifth years after the implementation of the ICL. Soil samples, taken from the 0-0.10 and 0.10-0.20-m soil depths, had sandy texture: 126 and 132 g kg^-1 clay, respectively. The following variables were evaluated: total organic carbon, soil bulk density (D_b), least-limiting water range (LLWR), and critical soil bulk density (D_bc). The physical quality of soil in the ICL system depends on the grazing height management on palisade grass in the autumn-winter period. Grazing height at 0.27 m provided the greatest values of total organic carbon and wider LLWR at 0.10-0.20-m soil depths. Palisade grass cultivation decreases more the frequency of soil samples with D_b>D_bc than soybean cropping, and grazing height of palisade grass contributes to the improvement of soil physical quality.

Index terms:
total organic carbon; soil compaction; critical soil bulk density; least-limiting water range; no-tillage; Arenosols.