Optimum levels in organs of N-P-K fertilized eggplants. II. Phosphorus parameters and cations

Eggplants (Solanum melongena L. cv. Bonica) were grown under controlled gre enhouse conditions at Almeria (Southern Spain). Treatments and dosages were the following: NH4NO3, N-1 (4 g/ m(2)), N-2 (8 g/m(2)), N-3 (16 g/m(2)); P O4H3, P-1 (13 g/m(2)), P-2 (26 g/m(2)), P-3 (52 g/ m(2)); K2SO4, 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 organi c matter (manure). We determine the optimum levels of cations (Ca, Mg, Na K ) and P forms and parameters in leaves and fruits of eggplant. The trend of the leaf and fruit P levels appears to indicate P translocation between th ese organs, negatively affecting fruit quality. We conclude that P transloc ation is caused by an increase in the fertilizer supply, confirming the dec line in quality under these conditions. The parallel trend between FAPA and inorganic P indicates that although the plants show suboptimum P levels, a deficiency of this element, as a result of FAPA was never found. The conce ntrations of divalent cations were high in the leaf and suboptimum in the f ruit. Fertilization induces accumulation of Na and K both in the leaf and i n the fruit.