NUTRIENT ACCUMULATION IN LEAVES OF MILLET, BRACHIARIA AND GUINEAGRASS

Abstract

Millet (Pennisetum glaucum), brachiaria (Brachiaria brizantha cv. Marandu), and guineagrass (Panicum maximum cv. Mombaça) are important grasses cultivated on cerrado soil of the Center-Western region of Brazil, and are used mainly for pasture, cover crops, silage, dry hay and seed production. The objective of this study was to evaluate the accumulation over time of N, P, K, Ca, Mg, Zn, Cu, Mn and Fe in the leaves of these grasses after emergence. The grasses were grown on a dystrophic dark-red latosolo (Oxysol/Hapludox) at Embrapa Arroz e Feijão, Santo Antonio de Goiás, GO. The treatments were arranged in a randomized complete block design with four replications, on plots 6.0 m wide by 20 m long. At planting, 400 kg/ha of 5-30-15 commercial-formula fertilizer was used. Sowing occurred in December, 2001 and during crop development nine leave samples were taken on different days after sowing for chemical analysis. Nutrient accumulation (Y) was determined and data were adjusted as a function of days after emergence (X) by a quadratic exponential regression model: Y= a exp(bx + cx2). Of the three grass species, millet accumulated the largest amounts of nutrients in leaves in the least time, followed by Panicum. Among macronutrients, higher accumulation occurred for N and K and lower for P. Among micronutrients, Fe accumulated the largest amounts.

KEY-WORDS: Gramineae; mineral nutrition; Brachiaria brizantha; Pennisetum glaucum; Panicum maximum.