Efeito de diferentes sistemas de pastejo em atributos físicos do solo

Abstract

In view of the importance of the interaction soil-climate-plant-animal to attain good yields in the system, the objective of this study is to evaluate changes in soil physical properties caused by grazing systems continuous and rotated. The systems were used: conventional (CC): Brachiaria brizantha cv. BRS Piatã, unfertilized annual replacement, managed under continuous stocking; fertilizer (AD): Brachiaria brizantha cv. BRS Piatã managed under rotational stocking system, with annual replacement fertilization with NPK at a ratio of 45-20-20 kg ha^-1 year^-1, and intercropping (IC): Consortium of Brachiaria brizantha cv. BRS Piatã and Stylosanthes Campo Grande, managed in a rotational system of stocking, fertilization receiving annual replacement with 00-20-20 NPK kg ha^-1 year^-1. To evaluate the effect of animal trampling on systems with rings were collected soil samples with undisturbed layers from 0.00 - 0.06 m, 0.06 - 0.12 m before and after grazing for the determination of soil density by the volumetric ring method, macroporosity and total porosity by the method of the tension table, were also collected samples deformed structure in the same layer for determining the organic matter content. The resistance to penetration was determined before and after grazing in the depths of 0.0 - 0.1, 0.1 - 0.2, 0.2 - 0.3 and 0.3 - 0.4 m, with the impact penetrometer. Animal stepping changed only the microporosity, the use of different cropping systems and grazing no differences in relation to organic matter content. The soils of the conventional grazing system were more tendency to soil compaction measured by penetration resistance of roots.