ATRIBUTOS QUÍMICOS E DISPONIBILIDADE DE NUTRIENTES EM LATOSSOLO SOB DIFERENTES COBERTURAS

Abstract

The Caatinga biome has a significant land extension in the Northeast region presenting a characteristic and remarkable vegetal diversity, but it has been suffering with climatic and anthropic actions affecting directly on the chemical, physical and biological quality of the soil and in some cases, causing the desertification of the area. The soil is a supplier of nutrients and water for all crops and existing biota, but its misuse is causing serious problems in the production and nutrition of the crops used, as well as impairing the macro, meso and microbiota in the soil, that is, soil fertility. The implantation of other crops in areas with native vegetation cover can affect the quality of the soil by reducing the nutrients content and making them unfeasible in the soil solution. In this way, the objective of this work was to evaluate the effects of native vegetation replacement by pasture and agriculture on nutrient availability in a dystrophic Yellow Latosol in the Caatinga biome located in Piauí. Soil samples were collected in triplicates at depths of up to 1.00 m, but the chemical analyzes as pH, Al, N, P, K, Na, Ca, Mg were analyzed at depths of 0.00-0.10 m (T), CTC at pH = 7 (T), Base Saturation (V%), Aluminum Saturation (m%), and analyzed by the Tukey averages test at 5% probability in all chemical analyzes evaluated. The results presented Nitrogen contents between 0.43 g Kg-1 (lower value) in pasture and 0.82 g Kg-1 (highest value) in native forest; for Phosphorus the highest value was 7.07 mg dm-3 in pasture and the lowest value was 0.20 mg dm-3 in native forest and for Potassium the largest and lowest value was for pasture with 27.55 mg dm-3 and 9.74 mg dm-3 at different depths. However, the replacement of the native forest by the implantation of crops affected the acidity with the pH of 4.2 and a CEC of 3.69 cmolc dm-3, so the soil needs more conservation practices that increase the fertility of the soil.