Modification of soil physical attributes as a function of subsoiling operations under different managements1

Abstract

Subsoiler performance can be influenced by crop residue in the soil through different types of vegetation cover. In any of these cover systems, the use of subsoilers for decompaction changes soil physical properties. The present study aimed to evaluate soil physical properties in different management systems using several subsoiling speeds and soil depths. The experiment was conducted at IF Goiano, Morrinhos Campus, Goiás state, Brazil. A completely randomized design was used in a split-plot scheme with 12 treatments and five replicates, totaling 60 plots. The factors corresponded to two management areas (rainfed and pasture), two subsoiling speeds (2.5 and 4.5 km h-1) and three soil depths (0.00-0.015; 0.15-0.30 and 0.30-0.45 m). The main plot consisted of the two management areas and the subplot the combination of the other two factors. Penetration resistance, bulk density, water content, soil mobilization and soil volumetric expansion were evaluated. The results were then submitted to analysis of variance and Tukey’s test (p ≤ 0.05). Penetration resistance and bulk density differed before and after subsoiling. The subsoiling speeds altered penetration resistance and soil mobilization. Pasture areas showed greater root penetration resistance, provided lower water content and favored greater soil volumetric expansion.