Alterações na estrutura do solo e anisotropia dos poros sob pisoteio animal e tráfego de maquinário

Abstract

The use of heavy farm machinery and excessive animal trampling can exert a lot of pressure on the ground. When this pressure exceeds the ability of the soil to resist for the modification of the soil structure, which often gives evil way. The pressure favours the reorganization of particles and aggregates, increasing the bulk density of soil and interfering with macroporosity, on aeration porosity, thus indirectly affecting the water retention and the development of plants, which brings harm to the quality of the soil. The loss of the physical quality of the soil has become more frequent in our areas, and due to these conditions of degraded soils, there is a need to study and use the existing soil physical quality in order to monitor land degradation. In this work we evaluated the first issue two types of forage management before the summer and your culture influence on soil quality. The treatments used were: Regeneration 103: that consisted on the removal of the animals for forage regeneration 103 days and Regeneration 20: that consisted in the removal of the animals to forage regeneration 20 days before planting soybeans, in two different sampling times: before planting and post-harvest of the culture of soybean. Soil quality did not suffer great interference in relation to animal trampling, evaluated by indicators assessed, however is the reduction of bulk density of soil on surface layer, due to use of the sulcadora rod, favoring the reduction of bulk density. The VESS (Visual Evaluation of Soil Structure) proved to be adequate to evaluate the forage management, because it was possible to notice an improvement in the quality of the soil structure, mainly in the regeneration 103. The grain yield of soybean was not affected in the presence of surface layers compacted soil. On the second issue the objective was to quantify the degree of anisotropy of the porous system due to compression, specifically in the variables of soil aeration and aeration pores, and the use of forage turnip as possible biological subsoiler influencing on structural improvement of the soil. In the compression experiment carried out in Denmark, the treatments used were: M8 (consisted in applying a load of 8 tons to the ground by an agricultural machine) and there was the addition of the Aarslev treatment without subsolador (which consisted of an area that has not been used the subsolador, while in other areas the use of subsolador. In Aarslev, the machinery has influenced directly the soil compaction due to treatment M8 had your aeration porosity and permeability of air reduced significantly as compared with control treatments and without subsolador. Points out that treatment without subsoiler (six years before the implementation of the experiment of compression), had no effect on the results, revealed by their values of Ka and εa which were statistically similar to control. Experiment of improving compression with turnip-barley rotation, the use of forage Turnip couldn't have a visible impact on the properties studied, as the Ka and εa in Aarslev and Flakkebjerg. The study of the anisotropy was not influenced by compression, except in Flakkebjerg for Ka values vertically approached the horizontal, demonstrating an impact compression.