effects of phosphorus and zinc on chemical composition of leaves and nutmeat weight in walnut

walnut tree is grown for multiple purposes. indeed, it is economically important and increasing its yield and improving its quality in order to compete in the international markets is one of great importance. to this end, one significant management practice is proper use of suitable fertilizers. zinc and phosphorus are two important elements in the nutrition of walnut. in this study, experiments were conducted with 3 phosphorus levels (0, 150, and 300 kg p2o5.ha-1) and 3 zinc levels (0, 15, and 30 kg zn. ha-1) by using factorial arrangement in randomized complete blockdesign with four replications. addition of phosphorus significantly affected concentration of p and fe in the leaves. phosphorus application of 150 kg.ha-1significantly increased copper concentration in the leaves. but, the application of higher levels of phosphorus decreased it. also, zn application increased its concentration in the leaves, but significantly decreased concentration of p in the leaves. the results of the study showed p application of 150 kg.ha-1significantly increased the dried weight of nutmeat, but application of higher levels of phosphorus decreased it.