Impactos de meios de exploração nos atributos físicos e químicos de um latossolo argiloso na Região Oeste do Paraná

Abstract

Soil exploitation methods, especially for agricultural activities, have played a fundamental role in human development. However, intensive soil use, destruction of native forests, and irresponsible use of natural resources have caused significant problems for soil quality and the environment. The objective of this study was to evaluate the impacts of soil exploitation methods on the physical and chemical attributes of a clayey Oxisol in the western region of Paraná. The soil exploitation methods were evaluated at the Institute for Rural Development of Paraná (IDR- Paraná), located at Santa Tereza do Oeste, Paraná, Brazil. Six soil exploitation methods were evaluated [No-tillage system with crop rotation (NT C/ROT), no-tillage system without rotation (NT W/ROT), fruit cultivation, pasture, crop-livestock integration (CLI), and native forest], with four replications. Physical analyses (soil bulk density, macroporosity, microporosity, total porosity, saturated hydraulic conductivity, and geometric mean diameter (GMD)) and chemical analyses [pH (CaCl2) and levels of potassium, phosphorus, calcium, magnesium, and organic matter] were performed at depths of 0-10, 10-20, 20-30, and 50-60 cm. The data were subjected to the non-parametric Kruskal-Wallis test at a 5% significance level and correlation analysis. The no-tillage system with crop rotation showed chemical soil conditions similar to those of native forest, followed by CLI and fruit cultivation. Pasture showed intermediate changes in soil chemical attributes. The no-tillage system without rotation showed signs of possible nutrient leaching and depletion, as well as low organic matter replenishment. Surface soil density was lower in no-tillage systems compared to perennial systems such as CLI, pasture, and fruit cultivation. Deep soil macroporosity in fruit cultivation and pasture systems was similar to native forest. Regarding the geometric mean diameter in the soil surface layer, the no-tillage system with rotation was similar to native forest. In general, positive correlations were observed between pH, Ca, K, base saturation (BS), cation exchange capacity (CEC), and base saturation percentage (V) with macroporosity and saturated hydraulic conductivity (Ksat), and negative correlations between soil density and chemical soil attributes. A correlation was found between soil macroporosity and Ksat, given that they are dependent variables: the greater the percentage of macropores, the higher the water infiltration in the soil. "This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001"