Resumen

SANABRIA¹, Damelys et al. Evaluation of three tillage systems in the recovery of a degraded pasture of Brachiaria humidicola. Zootecnia Trop. [online]. 2006, vol.24, n.4, pp.417-433. ISSN 0798-7269.

During three years, on a sandy loam soil, in Monagas state savannas, Venezuela, it was evaluated the effect of tillage in the recovery of a degraded pasture of Brachiaria humidicola and its influence in the physical and chemistry properties of the soil. The treatments were: Pasture without tillage (WT), conventional harrow (CH), and one pass of harrow plus one pass of sub-soiling at 40 cm of deep (H+S), using a randomized block design, with three repetitions of 1100 m²  each. At the beginning of the experiment it was applied 400 kg of acidulated phosphate rock and three months later, 100 kg/ha of urea and 100 kg/ha of K₂SO₄. The second year it was applied urea, K₂SO₄ and MgSO₄, using 100, 100 and 50 kg/ha, respectively. During the rainy and transition periods, it was measured the cover, height, frequency, production of aerial biomass in dry base, and contents of phosphorus, potassium, calcium, and magnesium in the plant. In all treatments, there was a recovery of the pasture in the studied variables. The H+S system caused a rapid recuperation of the pasture for cover and aerial biomass with statistical differences with treatments WT and CH, whereas for height and plant frequency, the systems WT and H+S showed identical values; however, these treatments were identical at the end of the experiment. In the evaluated treatments, the contents of phosphorus and potassium satisfied the critical values of the plant and the minimum requirements for bovines at grazing, but not for calcium and magnesium.

Palabras clave : tillage; degraded pasture; savannas; Brachiaria.