The effect of increasing organic fertilizers under reduce chemical fertilizer on the nutritional status and productivity of Navel Orange trees in the sandy soil

Abstract

Field experiment was conducted on the Navel orange trees in the Kassasin Horticulture Research Station Ismailia governorate to study the effect of the use of additional rates of organic fertilizer farmyard manure on the nutritional status of the trees and productivity under conditions that reduce chemical fertilization rates. Reducing the chemical fertilization levels of Nitrogen, Phosphorus and Potassium and increased manure quantities at rates of 5%, 10%, 15%, 20%, 25% and 30% and that for the amounts used in the control treatment. The results showed a slightly decrease of the leaf content from N, P, K and Ca while there was an increase in the content of Mg, Fe, Zn and Mn in all treatments. Decrease in nitrogen and phosphorus was significant if it add manure at equal rates to chemical fertilizers, while it was not significant when added at double rates from chemical fertilizers. The potassium deficiency was not significant for all treatments except when add manure by 15% (T3), as for calcium deficiency was significant in all cases. It was the previous results for the content of elements for a direct effect on the crop, which decrease to a large extent significant or not significant for the treatment of control rates by adding manure.