EFFECT OF PARTIAL REPLACEMENT OF MINERAL NITROGEN FERTILIZATION BY ORGANIC FORM ON YIELD AND LEAF MINERAL CONTENT OF NAVEL ORANGE TREES

Abstract

The experiment was conducted on the Navel orange trees in the Kassasin Horticulture Research Station Ismailia governorate to study the effect of replacement of mineral nitrogen by organic fertilizer farmyard manure (FYM) on the nutritional status of the trees and productivity under conditions that reduce chemical fertilization rates. Reducing the mineral fertilization levels of Nitrogen, and increased manure percentage of 5%, 10%, 20%, 30%, 40% and 50% from actual mineral nitrogen of control. The results showed that the leaf N, P, Mg, Fe, Zn and Mn content increased by increasing the percentage of organic form. All treatments gave nearly the same trend of control for leaf K content. Leaf calcium content was lower in all treatments compared with control. Yield kg/tree was higher with the three higher percentages of organic nitrogen which gave the same values as control. Leaf chlorophyll content increased by increasing organic nitrogen percentages. The effect of organic source cleared in the second season than first season on fruit weight. The first three treatments of organic source were nearly as higher as control than the last three treatments. Key words: Fertilization – Leafs Mineral Content - Navel Orange -Nitrogen - Organic Form - Yield.