Two field experiments were carried out on a Red Yellow Latosol (Hapludox), at São Carlos, SP in order to determine the rates of N, P, and K to obtain maximum economic return per area of forage yield for the oat line UPF 87111 grown in two planting systems: conventional tillage and mulch-covered. The experimental design was a fractionated factorial type (1/2)4³, with two blocks. The treatments consisted of four rates of N and K2O (0, 70, 140, and 210 kg ha-1), using urea and potassium chloride, and four rates of P2O5 (0, 60, 120 and 180 kg ha-1), using triple superphosphate. The N, P, and K rates for maximum profit were, in kg ha-1 for conventional tillage: N = 160, P2O5 = 180, K2O = 180; and for mulch-covered: N = 200, P2O5 = 120, K2O = 95 resulting in forage yields of, respectively, 7,398 and 8,111 kg ha-1 of dry matter. In both planting systems, the use of nitrogen resulted in higher forage yield per unit of applied fertilizer.
Avena sativa; forage yield; nitrogen; phosphorus; potassium
