Evaluation of cropping impact on chemical and aggregational characteristics in oxisol in the northwest of the state of Paraná

Abstract

The objective of this research was to quantify the soil chemical and aggregation modifications in oxisol located in the northwest of the state of Paranáe, Brazil, under native forest and cultivated soil. Samples were collected on sites of 0-20cm deep. The pH values, organic matter, macronutrients and dry size aggregate distribution were determined. The results indicated effects of the soil use on the evaluated chemical characteristics. The pH values, P, Mg²⁺ and base saturation increased in the cultivated area in comparison with the native forest. However, the levels of the Ca²⁺ and K⁺ did not differ between the systems evaluated. The results obtained indicated that the soil use and management resulted in reductions in soil organic matter and in the cations exchange capacity. The evaluations of soil structure using dry size aggregate distribution indicated larger sizes aggregates and larger frequency of higher aggregates in the cultivated soil