Resist?ancia mec?￠nica do solo ?? penetra?§?￡o em sistema silvipastoril ap?3s onze anos de implanta?§?￡o

摘要

Along with the growing demand for food, the need arises for intensification in the land use, converging to production systems with sustainability characteristics. An alternative one, applied to agriculture, is the adoption of integrated systems of agricultural production like the silvipastoral system. The integration between production systems aims to maximize the use of natural resources and inputs, with less impact on the environment and greater productivity gain in the area. In this sense, the long-term effects promoted by silvipastoral systems on soil, the physical attributes should be studied and reported in the scientific literature. The objective of this work was to evaluate the mechanical resistance of the soil to penetration (RMP) in longitudinal strips distributed between rows of trees planted in two arrangements, East-West and North-South, of a soil under a silvipastoral system, after 11 years of its implementation. The tree species implanted in 2006 was Grevillea robusta and, as forage species, Tifton 85 (Cynodon spp.) under pasture with rotated dairy cattle. In order to determine the RMP, soil layers of 0.0-0.05; 0.05-0.10; 0.10-0.20 and 0.20-0.40m depth were evaluated using a digital penetrometer. The experimental design used was that of random blocks with three repetitions. The arrangement of the trees was not considered as an experimental factor and the analyses were made in isolation within the East-West and North-South arrangement. The results showed that the highest RMP values were observed in the 0.05-0.10 m layer and in the strips close to the trees, due to the greater permanence of the animals in these locations. The burlap deposited in the soil by the trees and the root system of the fodder species should have helped so that the levels of RMP were lower at the soil surface, considering the increase in organic matter contents at the soil surface. The effect of the root system of the tree species may have contributed to higher RMP values at depths of 0.20 to 0.40m for east-west disposition.