Adubação nitrogenada e potássica em capim-elefante cv. Napier sob pastejo rotativo

This work was conducted at Leopoldina-MG with the objective of evaluate the effects of N and K combination doses on the availability and chemical composition of the forage and stocking rate of elephantgrass (Pennisetum purpureum Schum. cv. Napier) pasture under rotational grazing. In an area of 4.5ha, a factorial combination of three N doses (100, 200 and 400kg ha-1) and three K doses (50, 100 and 200kg ha-1 of K2O) was evaluated during four rainy periods (1997/98 to 2000/01). The experimental design was a randomized complete block with two spatials replicates. No effect was observed on K fertilization on total, leaf and stem dry matter production, chemical composition and animal production. However, the availability of total dry matter, leaf dry matter, stem dry matter and crude protein content were proportional to the N doses and they changed with the rainy periods. The N fertilization increased the availability of total, leaf and stem dry matter of elephantgrass, and it contributes to increase the stocking rate and the weight gain per animal and per area.