EFICIÊNCIA AGRONÔMICA DA FERTIRRIGAÇÃO NITROGENADA E POTÁSSICA NA CULTURA DO MELOEIRO NAS CONDIÇÕES DO SEMIÁRIDO NORDESTINO

Abstract

This work was carried out from october to december, 2005, in Agropolo Assu-Mossoró region, RN, Brazil, with the objective of evaluating the effect of nitrogen and potassium doses on fertilization efficiency of melon crop. Three simultaneous trials were performed in adjacent areas, each one receiving a different water amount (L1=0.76NTI, L2=0.9NTI and L3=1.04NTI). Experimental design was a randomized blocks in a factorial scheme with three replications. Treatments consisted of combination of three doses of both nitrogen (N1=42, N2=84 and N3=126 kg ha-1) and potassium (K1=106, K2=212 and K3=322 kg ha-1), plus two additional treatments (N2K0 e N0K2), applied only with intermediary water amount. N2 e K2 was the levels recommended for melon. Indexes of agronomic efficiency of fertirrigation were determined for nitrogen, potassium and irrigation depths. Agronomic efficiency was influenced by N and K doses, irrigation depths and by factor interaction. Treatments L3N1K1 (305.57 kg kg-1) and L3N2K1 (132.63 kg kg-1) presented higher efficiencies for fertirrigation with nitrogen and potassium, respectively.