Yield and botanical composition of a mixed grass-legume pasture in response to maintenance fertilization

Abstract

-This study was carried out on a low-productive Brachiaria brizantha cv. Marandu pasture, mixed with Arachis pintoi cv. Belmonte (forage peanut), established 13 years ago in a Red-Yellow Latosol in Acre State, western Brazilian Amazon. The purpose was to evaluate the response of this pasture to different fertilizer combinations, aiming at identifying the nutritional factors responsible for the fall of pasture carrying capacity and for the reduced vigor of forage peanut. It was used a randomized complete block design, with three replications and 12 combinations of nitrogen, phosphorus, potassium, lime, sulfur, and micronutrients (100 kg/ha of N, P 2 O 5 and K 2 O; 300 kg/ha of dolomitic lime; 30 kg/ha of sulfur and FTE BR-10).Fertilizers were broadcast in 5 × 5-m plots, and the experimental area was isolated from grazing for 35 days. Pasture response to fertilizations showed that nitrogen was the main limiting nutrient to forage production. The other nutrients, applied singly or in a combined way, without nitrogen source, did not change dry matter accumulation rate. Overall, fertilizations with nitrogen provided dry matter accumulation rate of 115 kg/ha/day in comparison to only 32 kg/ha/day when nitrogen was not applied. There was no response from forage peanut to fertilization, so, there are other factors responsible for its reduced vigor of regrowth.

Nutrient status of cattle grazing systems in the western brazilian amazon

“…The concentration of P in kudzu (1.7 g kg -1 ) was less than the amount required by temperate perennial legumes (2.1 g kg −1 to 3.1 g kg −1 ) (Davis, 1991). Evidence from the Amazon region indicates that nitrogen is the most limiting soil nutrient for high pasture productivity (Andrade, Valentim, Pereira, & Ferreira, 2010).…”