Chemical and physical attributes of a yellow distrofic oxisol and root growth of Brachiaria decumbens submitted to fertilization and subsoiling

Abstract

Pasture degradation is an evolutionary process of losing vigor, productivity and capacity of natural recovery of pastures. It can economically cripple the production and the forage quality required by the animals. This process can have a physical and/or chemical and/or biological origin. The aim of this study was to evaluate the effects of tillage, liming and fertilization on a yellow distrofic oxisol from a oastal land zone and its consequences on Brachiaria decumbens root system. The experiment was located at UFRB experimental area, Cruz das Almas – BA, Brazil. The experimental design was arranged in a split plot, with two tillage treatments: heavy disc harrowing (Gp) and heavy disc harrowing + subsoiling (Gp + Subs) in three blocks and five fertilizers combinations: control (Test.); liming (Cal); NPK; NPK + Cal; and Cal + Agricultural Gypsum + NPK (CalGA + NPK). Were evaluated: density, porosity and the mechanical resistance of soil to penetration, pH, Al3+ and V% values and also root density. It was observed that the effect of subsoiling on soil physical attributes lasted for two years, increasing soil porosity and decreasing soil density and resistance to root penetration. Subsoiling interacted with lime leading to a depth correction.