Intervalo hídrico ótimo em latossolo vermelho distrófico sob cerrado nativo e cultivo mínimo com soja

Abstract

The State of Mato Grosso, particularly in the coverage of the Cerrado has been highlighted in the cultivation of soybeans, mainly managed in minimum tillage. Parallel, increased the use, the weight and the power of agricultural machinery. In agricultural areas, soil compaction and excessive structural degradation of the soil is a major constraint on water availability to plants. Therefore, understanding of how production systems influence soil structure is fundamental to the management of soil water. In this context, the objective was to determine the impact of minimum cultivation system in an Oxisol under soybean cultivation for eight years in succession on soil physical properties and their interaction with the least limiting water range (LLWR), based on an area Cerrado native as a reference in terms of structural quality in the layers 0-10, 10-20 and 20-30 cm. It was found that: in minimum tillage was mainly in the 0-10 cm layer, significant increase in bulk density and decrease in organic matter, the degree of flocculation and stable macroaggregates (4-2 mm); ii) a reduction in the IHO to 20 cm and severe structural degradation in surface reflection of soil compaction, where the average soil density based on the confidence interval had the highest proportion out of the IHO; (iii) also showed higher proportion of samples, where θPAR (≤ 10%) and θRPlimite replacing θCC and θPMP, however regardless of the adopted management found Dscríticas values similar and therefore the density range appears to be inherent to soil. Furthermore, the IHO was positively correlated with the percentage of stable macroaggregates (4-2 mm), organic matter, degree of flocculation, however negatively correlated with microaggregates (2-1 mm) and bulk density, confirming the importance of the structural quality soil to improve water availability for growth and development of plants.