Mineral nutrition of Panicum maximum cv. Makueni I: growth, concentration and accumulation of the macronutrients

Abstract

Makueni being a promissing specie for Brazilian cattle raising, the present work was carried out to determine weight of dry matter production, concentration and accumulation of macronutrients from 30 days after cutting the grass up to 180 days old. For the purpose and area comprising 600 m² of Latossolo Vermelho Amarelo (Oxisol) at São Carlos, State of São Paulo, Brazil on the farm Canchim, research institute wich belongs to EMBRAPA, the trial was conducted the meadow was cut and fertilized with ammonium sulphate at the rate of 250 kg/ha. At intervals of 30 days after the cutting up to 180 days plants corresponding to one square metre were collected. The dry matter content was determided and the material was analysed for N, P, K, Ca, Mg and S. The maximum production of dry matter is checked at 120 days represented by 1,425 kg/ha. The fasted dry matter production occur around the 60 days after cutting the meadow. The concentration of N is higt at the 30 days (1.62%) and low at the 120 days (0.72%). The concentration of P is highest at the 120 days (0.87%) and lowest at the 60 days (0.003%). The concentration of K is linear with the age of the grass. The concentrations of K change from 2.8% at the begining to 0.76% after 180 days. The concentration of Ca is highest at the 90 days (0.53%). There are not variation in the concentration of Mg in function with the age of the grass. The concentration of S chang of 0,14% at the 30 days for a lowest at the 120 days (0.07%). The accumulation of P, K, Ca is highest at the 90 days. The accumulation of Mg is highest at the 120 days and S accumuled the highest amounts at the 60 days. The greatest amounts of nutrients content in 1.425 kg/ha of dry matter obey the following order: K - 30.4 kg; N - 13-9 kg; Ca - 7-0 kg; Mg - 6.3 kg; S - 1.3 kg; P - 1.2 kg.