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

Eggplants (Solanum melongena L, cv. Bonica) were grown under controlled gre enhouse 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 p resent study we have determined whether commercial yield in commercially gr own eggplants is altered by progressive increments of N, P and K together w ith organic matter vs. a treatment without inorganic Fertilizers. We conclu ded that excessive N applications lower yield quality and quantity, thereby substantially diminishing commercial profits, while appropriate rates incr ease 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 boos ts non-commercial. yield. Our findings on the different K rates together wi th organic matter in relation to yield indicate that biological, commercial , and noncommercial yield register maximum values with the minimum fertiliz er 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.