NITROGEN-METABOLISM AND YIELD RESPONSE TO INCREASES IN NITROGEN-PHOSPHORUS FERTILIZATION - IMPROVEMENT IN GREENHOUSE CULTIVATION OF EGGPLANT (SOLANUM-MELONGENA CV BONICA)

The effect that application of nitrogen-phosphorus (NP) rates exerts o n some parameters of nitrogen metabolism and on yield in aubergine pla nts (eggplant, Solanum melongena cv. Bonica) was studied. All plants w ere grown under controlled conditions in an experimental greenhouse. T he treatments consisted of the combination of three rates of N in the form of KNO3 (N-1: 15 g m(-2), N-2: 22.5 g m,(-2) and N-3: 30 g m(-2)) together with two rates of P in the form of H3PO4 (P-1: 24 g m(-2) an d P-2: 36 g m(-2)), for a total of six treatments. Results indicate th at regardless of the P rate applied, an increase in the N fertilizer i ncreased NO3-assimilation as well as total and commercial yield. Use o f the P-2 rate favored all of these processes in comparison with the r esults obtained with the P-1 rate, in addition to notably reducing the foliar levels of NO3-and noncommercial yield.