PHYSICAL ATTRIBUTES OF SOIL UNDER LEGUME-GRASS CONSORTIUM IN NORTHERN TOCANTINS STATE, BRAZIL

Abstract

The aim of soil management is to improve the chemical, physical and biological attributes to allow for optimum crop development. The experiment was done in two classes of soil (Entisol and Oxisol), at the school of Veterinary Medicine and animal husbandry of Tocantins Federal University. The objective of the work was to evaluate the effect of legumegrass consortium on soil quality determined by quantifying the physical attributes. The soils were planted to either of the following four grass and two legume crops, either alone or in consortium: Brachiaria brizantha cv Marandu, or cv MG-5, Panicum maximum Jacq cv Tanzânia or Mombaça, Stylosanthes. capitata + S. macrocephala cv Campo Grande, and S. guianensis cv Mineirão. The experiment was laid in completely randomized design with 14 treatments in four replications, in two separate experimental areas. Soil moisture, density, porosity and soil resistance to penetration (RP) were determined. In Entisol soil RP increased with concurrent decrease in porosity, while in Oxisol no negative correlation with porosity was found. In Entisol the response of density relative to the initial values was positive to the treatments. The grass pasture crop Tanzânia or Mombaça, consorted with Stylosanthes capitata + S. macrocephala reduced compaction in Entisol. In Oxisol Marandu grass planted alone or consorted with S. guianensis had smallest RP values. The RP values in two soils are similar only to the depth of 0 to 10 cm and 50 to 60 cm, while at other depths Oxisol soil showed higher resistance to penetration.