Alterações em propriedades físicas de um latossolo da região sudoeste dos Cerrados por diferentes sistemas de uso e manejo

Abstract

Agricultural activities have caused negative impacts in Cerrado Region, mainly on the quality of the soil and the water. Both in systems of agricultural exploitation or livestock, with different management, the physical degradation of the soil is one of the consequences of the productivity reduction. In this context, physical properties of soil like the porosity, the bulk density, the resistance to the penetration, the aggregation and the water infiltration rate can be used as indicative of physical quality of the soil. The search for systems of soil management, as those that integrate agricultural and livestock, which have aimed at the recuperation and or maintenance of the qualities cited above, is fundamental in the most sustainable management of the livestock. The hypothesis of this work is that the use of soil in the integration agricultural and livestock improves its physical properties, contributing this way, to a sustainable agricultural exploitation of soil in the southwest region of Cerrado. The main purpose of this work was to verify the influence of different systems of management in some physical properties of a soil in the region of Cerrado. In Cerrado region, the soil is classified as dystrophic Oxisoil, where were evaluated the following systems of management: a) soil under natural vegetation; b) soil with soy farming implementation during a year and followed by three years of pastures; c) soil with soy crops implementation during four years, continued by four years of pasture; d) soil with crops of continuous soy in system of under no tillage system; e) soil with pasture continuously. Were evaluated, in the period of 1995 to 2002 the infiltration of water in soil, the porosity of soil, the density and the resistance of soil to the penetration and, in the period of 1995 to 2006, was evaluated the stability of the aggregate in water. When compared to the soil under natural vegetation, the utilization of forage Brachiaria decumbens as continuous pasture, provided smaller impact in the physical properties of the soil, related to the management with integration agricultural and livestock and continuous crops productivity. The management of soil in no-tillage system, over the years, causes the reduction of the macroporosity, increase of the density and of the resistance of soil to the penetration in the superficial layers. In agricultural and livestock integration systems, the effect of pasture trampling causes, in the superficial layers of soil, more significant reduction of the macroporosity, increase of the density and of the resistance of soil to the penetration than the implements and machines utilized in the system and no tillage system. The management of soil, with crops productivity, in Cerrado would be able to be intercalated with periods of pasture to improve and or, maintain the physical quality of the soil.