Teores de nutrientes na folha e nos grãos de aveia-preta em função da adubação com fósforo e potássio

Black oat is a rustic gramineae, with low requirements, mainly cultivated as winter forage and green manure in crop rotation systems. In spite of its importance, there are only few studies evaluating the effects of fertilization on nutrient content in their leaves and grains. The objective of this work was to study the effects of P and K fertilization on the concentration of macro and micronutrients in flag leaf and grains of black oat cv. Comum. An experiment was carried out under field conditions on a Rhodic Nitisol, in Botucatu, São Paulo State, Brazil. Three doses of P (0, 40 and 80 kg ha -1 of P 2O 5) and three doses of K (0, 20 and 40 kg ha -1 of K 2O), in presence of 50 kg ha -1 of N (20 kg ha -1 applied at sowing and 30 kg ha -1 after tillering stage) were tested, in a factorial 3 × 3 randomized complete block design, with four replications. Macro and micronutrients concentration in flag leaves increased with phosphorus fertilization; 40 kg.ha -1 of P 2O 5 was sufficient to promote these positive results. Potassium fertilization affected only the concentration of K in the leaves. Nutrient concentration in grains were not affected by phosphorus or potassium fertilization.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq