Adubação fosfatada no diferimento e rebrota do capim marandu

Abstract

The objective was to evaluate the potential of phosphate fertilization as a strategy to produce a deferred pasture and to verify the potential residual effect of this fertilization for the regrowth of Marandu grass in the next rainy season. The experimental design used was a randomized block design with treatments arranged in a 2 x 5 + 1 factorial, with two phosphorus sources (simple superphosphate and Arad reactive natural phosphate) and five phosphorus doses (0, 25, 50, 75 and 100 kg ha-1 of P2O5), with four repetitions and one additional treatment without any type of fertilization (control). The variables evaluated were: height, tiller population density, forage dry mass, total dry mass, root dry mass, leaf: stem ratio, percentage of dead material and percentage of soil cover. The growth and production of Marandu grass in the deferral were benefited by fertilization and mainly by the inclusion of phosphorus together with nitrogen and potassium (N and K2O). The single superphosphate source was shown to be superior to Arad in benefiting forage development at deferral. Phosphate fertilization favored the accumulation of biomass by Marandu grass, contributing to the recovery of degraded pasture. Fertilization of Marandu grass at deferral had a residual effect on height, tillering and forage production at regrowth. Marandu grass showed positive responses in relation to phosphorus sources. Arad rock phosphate can be a long-term alternative for use in conjunction with a soluble source to supplement the supply of P2O5. Advance fertilization with Arad improves its solubilization and forage performance in the next rainy season.