Relationship between leaf yellowing degree and nutrimental elements levels in navel orange (Citrus sinensis Osbeck) leaves in southern Jiangxi province of China.

【Objective】 In order to explore the reasons for leaves yellowing of navel orange in southern Jiangxi province,nutrimental elements contents of Newhall navel orange leaves were studied.【Methods】 Nutrimental elements of Newhall navel orange(Citrus sinensis Osbeck) trees' leaves on trifoliate orange [Poncirus trifoliata(L.)] rootstocks in 78 orchards in southern Jiangxi province of China were analyzed in 2008.【Result】 P,S,Mo and B contents of these leaves were in the optimum range,while N,K levels were higher than the optimum range.Fe content also was in the optimum range or above.Except for individual orchards,Mn content of leaves was in the desirable scope.Ca and Cu contents of leaves in part of the orchards were lower than optimum range.Furthermore,there was significantly lack for Mg content of leaves in the yellow orchards.With the increasing of leaves yellowing degree,Mg content of leaves was significantly declined(P0.05).In addition,Zn content of leaves wasn't only deficient in the yellow orchards,but also Zn content of leaves in normal orchards was significantly lower than the optimum range.【Conclusion】 N,P,K,S,Fe,Mo and B contents of leaves weren't deficient in yellow orchards of southern Jiangxi province of China.And leaf yellowing phenomenon generally weren't due to the deficiencies of Ca,Mn and Cu,mainly concerned with the deficiencies of Mg and Zn.