ACURACIDADE DE INDICADORES DE QUALIDADE FÍSICA DO SOLO NA AVALIAÇÃO DAS ALTERAÇÕES ESTRUTURAIS DO SOLO EM SISTEMAS INTEGRADOS DE PRODUÇÃO AGROPECUÁRIA

Abstract

The crop-livestock integration system together with the direct planting system is one of the conservationist production alternatives that producers have sought to increase productivity and reduce soil degradation. However, the diagnosis of soil structure still needs refinements when it comes to choosing the indicator attribute that best represents the characteristics of the soil environment. This doctoral thesis aims to evaluate the accuracy of soil physical quality indicators in the assessment of soil structural changes in integrated agricultural production systems. To this end, two studies were carried out that constitute its chapters. In the first chapter, with the objective of evaluating the potential for soil biological decompression by paiaguás grass and the effectiveness of integrated systems in the agronomic performance of soybeans, soybean cultivation was implemented under three management systems (simple: monoculture grains and integrated: intercropping between grass and grains and pasture in monoculture). Soil density (Ds) and optimal water range (IHO) were determined, which indicated that integrated agricultural production systems alleviated soil compaction and improved soybean development. The adoption of paiaguás grass in monoculture enhanced the soil benefits and enabled greater grain production compared to the simple grain succession system. While the IHO proved to be efficient in modeling the physical behavior of the soil, this study also advanced in improving it in relation to the penetration resistance reference values specific to each management system. In the second study, the objective was the effectiveness of 21 physical attributes indicating structural quality in a Red Latosol cultivated long-term and in different integrated production systems, in addition to establishing agronomic and environmental functional relationships. To this end, eight treatments were evaluated: continuous pasture, crop-livestock integration under conventional system, crop-livestock integration under direct planting, livestock-crop integration, livestock phase under direct planting, continuous cropping under conventional system, continuous cropping under direct planting, native cerrado. Deformed and undisturbed soil samples were taken at 0.00-0.05; 0.05-0.10 and 0.10-0.20 m. Use and management differentially affected the physical quality of the soil. Integrated agricultural production systems proved to be adequate, especially those under direct planting. The subsurface layers had the greatest sensitivity to structural changes and can be considered in the soil physical diagnosis. Of all the attributes evaluated, macroporosity proved to be most effective as it is primarily achieved by soil compaction.