PHOSPHORUS SOURCES AND LEVELS FOR PASTURES OF Brachiaria brizantha cv. MARANDU IN THE SOUTH OF THE TOCANTINS STATE, BRAZIL

Abstract

The objective of this study was to evaluate the response of Brachiaria brizantha cv. Marandu to the sources and doses of phosphorus for the production of dry matter mass in a dystrophic Oxisol at Gurupi, Tocantins State, Brazil. The treatments were arranjed in a factorial 3x5+1: three sources of P (triple superphosphate – ST, natural hyperphosphate of Gafsa – HG, and natural phosphate reactive – FP), and five doses (33%, 66%, 100%, 133% and 166 % of recommended dose of P2O5 – 90 kg ha-1), plus a control without P. The experimental design was randomized complete blocks with three replications, having totalized 48 plots of 20 m². There were significant effects (p < 0.05) of P sources and doses used. Among the sources, ST provided the highest yield of dry mater mass in all doses evaluated, except for 30 kg ha-1 of P2O5, where the superiority was not significant. Between the sources less soluble (HG and FP) did not observed significantly difference. It was concluded that for the growth of B. brizantha cv. Marandu, in the evaluated conditions, the use of ST promotes greater production of dry matter, with incresing response under incresed doses. The 120 kg ha-1 and 150 kg ha-1 of P2O5 doses had provided highest field of dry matter mass.

KEY-WORDS: Gafsa; triple superphosphate; natural reactive phosphate; MS production.