Effect of Sources and Rates of Nitrogen on Nutrients Extraction in Coastcross Pastures

The contents and the extraction of mineral nutrients were determined in a coastcross pasture established on a dark red latosol (Hapludox), in São Carlos, SP, Brazil, under tropical altitude climate, receiving five rates of urea and ammonium nitrate, applied on surface. There were differences (P\u3c 0.05) among sources and rates of N. Nutrients extraction increased with the nitrogen levels. Especially high were total N (319 and 446 kg ha-1) and K (341 and 467 kg ha-1) extractions. When forage yield was high (treatment with 500 kg of N ha-1) and for both fertilizers, macronutrients extraction was greater for K and N, followed by Ca, S, P and Mg. Micronutrients extraction occurred in the following decreasing order: Fe, Mn, Zn and Cu