Intervalos de corte e doses de potÃssio no rendimento e qualidade da forragem do capim-tanzÃnia / Cutting intervals and potassium doses on tanzania grass production and quality

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The experiment was carried out in field previously cropped with Tanzania grass in November of 1997, at the Animal Science Department area of the Federal University of Lavras, from August of 2001 to May of 2002, objecting to evaluate the influence of four cutting intervals (4, 6, 8 and 10 weeks) and three K2O doses (0, 100 and 200 kg/ha) on production and forage quality of Panicum maximum Jacq. cv. Tanzania 1. Initially, a soil analysis of experimental area was made; later on, maintenance fertilization was realized, by applying 150 kg/ha of N, as ammonium sulfate, 60 kg/ha of P2O5, as simple phosphate, and 50 kg/ha of K2O, as potassium chloride. The treatments were combined in a factorial 4x3 design, in randomized blocks with four replications. The experimental potassium fertilization was realized in broadcast method between lines of Tanzania grass, in two applications. Linear increments of tiller height and dry matter (DM) of Tanzania grass were observed by increasing cutting intervals. The tiller density and the leaf/stem relationship were independent of the applied treatments. Leaf area index (LAI) increased linearly with the increase of the doses of K2O and, in an exponential way, with the increase of cutting intervals. The crude protein (CP) contents reduced in an exponential way by increasing of cutting intervals. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) presented increase linear behaviour with the increase of cutting intervals. Linear decreasing of Ca and Mg contents were observed by increasing the potassium fertilizer doses. The increase of cutting intervals promoted linear decreasing of K, exponential of P and quadratic of Ca and Mg contents. Efficiency of K, N and P utilization was evaluated. The largest K efficiency of use was verified by application the medium dose of K2O. When considering the maintenance fertilization, the smallest efficiencies are observed for K in the largest doses of K2O but presenting a better plant nutrient usage. N and P presented, respectively, a low and medium efficiency of nutrient usage by plants.

ASSUNTO(S)

qualidade crescimento corte capim tanzÃnia quality rendimento cut forragem production zootecnia tanzania grass growth forage

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