Intervalo hídrico ótimo e índices como indicadores da qualidade físico-hídrica do solo

Abstract

In recent years, integrated agricultural production systems has proven to be a viable option because of the numerous benefits they provide, such as, increasing productivity, reducing production costs and improving the physical, chemical and biological soil. In the case of systems that integrate crop and livestock (iLP) there is a great concern for problems in physical properties and water the soil resulting from cattle trampling and machinery traffic. The objective of this study was to characterize the physical and hydraulic properties of an Oxisol managed under ILP in Goias Cerrado, using for that physical indicators of soil quality (soil bulk density, porosity and penetration resistance), limiting water range (LLWR) and the index S. The study was conducted in an experimental area of Embrapa Rice and Beans in iLP. The treatments were: Forest = Cerrado; iLP = Soy, Past. 1, Past. 2 and Past. 3, pasture with 1, 2 and 3 years of implementation time, respectively. Disturbed and undisturbed samples were collected in the layers 0.0 to 0.10 and 0.20-0.30 m. In the deformed specimens was determined texture, carbon content and soil fertility. In undisturbed soil samples were determined: soil bulk density (BD), water retention curve in the soil and penetration resistance (PR), which were subsequently used to calculate the IHO and the index S. Soil management with iLP affected the soil physical properties in relation to the Mata, observed by the increase in Ds, microporosity and RP and reduced macroporosity and total porosity. The soil physical behavior described by the IHO and the S were similar. Both demonstrated a degradation of soil physical quality in iLP regarding Woods, observed by low values of IHO S and for these treatments. They point to a structural soil degradation with the implementation of agriculture and a gradual improvement of soil physical quality with the set pasture deployment time, mainly by low IHO S values and the Past. 1 and higher in soybean and Past. 3, with Past. 2 showing intermediate values. The IHO indicates a severe structural soil degradation, the two layers evaluated for the treatment Past. 1 which can be attributed to recent traffic of agricultural machinery and implements for planting and harvesting practices in the area. The S-value indicates soil physical degradation to the Past treatments. 3, the first layer, Past. 1 and Past. 2 in both layers. Thus, these two indicators efficient to describe and quantify the effects of changes in soil structure by management with iLP in the Cerrado region. The management of soil under iLP was an efficient model in improving soil structure, mainly by the resilience and the beneficial effect of root used pastures.