Nutrient extraction by Marandu-grass phytomass under doses and nitrogen sources

Abstract

The research was carried through objecting to evaluate the nutrient extraction of marandu - grass phytomass, under doses and sources of nitrogen during three year period. The experiment was lead from July of 2003 to March of 2006 at the Model Farm of the UEG in a 882 m2 area. The pasture already had been established more than ten years with low fodder production. The used experimental delineation was a randomized block-type with subdivided parcels for the time, with three repetitions. Two nitrogen sources (ammonium sulfate and urea) and four nitrogen doses (0, 100, 200 and 300 kg ha-1.year-1) in a 2 x 4 factorial schem were used. In each one of the years, three cuts of forage plant evaluation had been carried through. The maximum doses of nitrogen have provided greater nutrient extractions. The second year evaluation and the ammonium sulfate source had been responsible for extracting higher nutrient amounts. The decreasing order of nutrient extraction for marandu - grass, in relation to the maximum doses of nitrogen was: macronutrients: K > N > Ca > Mg > P = S and micronutrients: Fe > Mn > Zn > Cu.