CULTURAL METHODS AND MINERAL-CONTENT OF EGGPLANT (SOLANUM-MELONGENA) FRUIT

Mineral content in edible portions of vegetables may be affected by cu ltural methods. This study was conducted to determine if fertiliser ra te and irrigation regime affected mineral (N, NO2, NO3, P, PO4, K, SO4 , Ca, Fe, Na, Mg, and Mn) of eggplant (Solanum melongena L, cv Black B ell) fruit. The experiment on a Bernow fine-loamy, siliceous, thermic Glossic Paleudalf soil at Lane (OK, USA) with three fertiliser rates a nd three irrigation regimes. The data were analysed as a split-plot wi th harvests as the sub-plot. All P was accounted for by PO4. Levels of NO2 and NO3 comprised <0.001% of the N content. Harvest number affect ed only N, P, K, SO4 and Mg levels in both years, and Na in one year. For many of the minerals the highest levels in fruit were not consiste nt over harvests in both years. When there was less precipitation, and fertiliser was applied at the recommended rate, fewer irrigations per week were necessary to increase levels of N, P and K in fruit. The in teraction of irrigation and fertiliser can affect mineral content of f ruit and should be considered when fertiliser recommendations are made .