Nutri？？o mineral de Andropogon gayanus Kunth var. bisquamulatus (Hochst) Hack: I. recrutamento de macronutrientes

as gamba grass (andropogon gayanus kunth var. bisquamulatus (hochst) hack) is a promising species for raising cattle, this work was carried out to determine weight of dry matter, concentration and accumulation of macronutrients from the 20 th day after germination up to flowering. for this purpose, an area comprising half a hectare of "terra roxa estruturada" at piracicaba, state of s？o paulo, brazil (latitude 20o41'31"s, longitude 47°38'01" wg, elevation 540m) suitably fertilized, was planted. at intervals of 20 days after germination up to 140 days, plants were collected and subdivided into leaves and stem. the dry matter at 80°c was analysed for n, p, k, ca, mg and s. the maximum production of dry matter was checked at 80 days represented by 13.82 g/plant corresponding to 50,000 kg per plant. at the age of 80 days, the following quantities of nutrients were extracted by the grass: 156.85 mg of n; 16.23 mg of p; 278.70 mg of k; 38.45 mg of ca; 22.92 mg of mg; 7.76 mg of s. it was found that the concentration of p and k diminished as the age of the plant advanced; the concentrations of n, ca, mg and s in the leaves were not affected. in the stem, there was a decrease in n, p, k, ca and mg as the age of the plant increased; the concentration of s was not affected.