Sources and Rates of Phosphorus in Improving Degraded Pasture in Brazilian West Amazon

The effects of phosphorus sources (triple superphosphate – TSP, single superphosphate – SSP and partially acidulated rock phosphate – PARP) and rates (0, 50 and 100 kg/ha of P2O5 on dry matter (DM) yields and chemical composition of a degraded Brachiaria brizantha cv. Marandu pasture were evaluated in a cutting trial. Phosphorus fertilization, irrespective of sources and rates, showed an effective agronomic technique for pasture recuperation. The grass DM yields and potassium contents were significantly improved by phosphorus application, while weed DM yields were depressed. Irrespective of sources and rates, crude protein, phosphorus, and calcium contents were not affected by phosphorus fertilization. The application of 100 kg of P2O5 /ha, as TSP, provided the highest grass yields, while for PARP it was observed the least effect of phosphorus fertilization