Eggplant yield response to increasing rates of N-P-K fertilization

Eggplants (Solanum melongena L, cv. Bonica) were grown under controlled greenhouse conditions. The treatments and dosages were the following: NO3NH4, N-1 (4 g/m(2)), N-2 (8 g/m(2)), N-3 (16 g/ m(2)); PO4H3, P-1 (13 g/m(2)) P-2 (26 g/m(2)), P-3 (52 g/m(2)); SO4K2 K1 (5 g/m(2)), K-2 (10 g/m(2)), K-3 (20 g/m(2)), K-4 (30 g/m(2)); and T-0 only organic matter (manure). In the present study we have determined whether commercial yield in commercially grown eggplants is altered by progressive increments of N, P and K together with organic matter vs. a treatment without inorganic Fertilizers. We concluded that excessive N applications lower yield quality and quantity, thereby substantially diminishing commercial profits, while appropriate rates increase biological yield. We confirmed that the economical optimum N rate was N,, especially due to the presence of organic matter. Like N, excessive P (P,) reduced yield and therefore profitability, although this reduction boosts non-commercial. yield. Our findings on the different K rates together with organic matter in relation to yield indicate that biological, commercial, and noncommercial yield register maximum values with the minimum fertilizer rate (K,). Grown with increasing rates of N, P and K in the presence of organic matter eggplantsdid not require high rates of fertilizers to attain maximum economic yield.