Propriedades químicas e resistência mecânica do solo à penetração em sistema silvipastoril após onze anos de implantação

Abstract

With the increase in the demand for food there was a need for intensification of land use, with several discussions on sustainable agriculture. One of the alternatives applied to agriculture is the adoption of integration systems such as silvipastoril, which aims to maximize natural resources and inputs, with less impact on the environment, and is considered economically viable, although, despite the areas destined to this system, becoming increasingly significant in Brazil, the effect promoted by silvipastoral systems on the physical and chemical attributes of the soil is little reported in the scientific literature. The objective of this work was to evaluate the mechanical resistance of the soil to the penetration and the macronutrient arrangement in five longitudinal strips distributed between tree lines planted in two different arrangements (East-West and North-South) at different depths under a silvopastoral system consisting of grevillea (Grevillea robusta), Tifton 85 (Cynodon spp.) and milk cattle (Jersey x Dutch Red) after eleven years of implantation. Soil samples were collected at depths of 0-5; 5-10; 10-20 cm, for determination of pH in CaCl2, and the contents of P, K, Ca, Mg, H + Al and values of MO, CTC, V%, SB, m%, and for determination of soil mechanical resistance Penetration (RMP) at depths evaluated were 0-5; 5-10; 10-20; 20-40 cm with the aid of a digital penetrometer; the experimental design was a randomized complete block design with three replicates and five treatments. The results showed that the concentration of nutrients evaluated was higher in the zone close to the trees, a fact associated with the animal behavior and the action of the vegetal cover on the soil. Regarding the physical attributes, the highest RMP values were observed in the 5-10 cm layer, in the bands near the trees, due to the longer stay of the animals in these places. The litter deposited on the ground by the trees helped to reduce the resistance levels in the first 5 cm. The effect of the root system of the tree species contributed to the fact that RMP levels remained high at depths of 20 to 40 cm for the EastWest arrangement.