Study on Leaf Nutrition of Newhall Navel Orange on Different Soil Types in Southern Jiangxi

Leaf samples of Newhall navel orange(Citrus sinensis Osbeck) were collected from 131 orchards,representing 4 different kinds of soils(clay red soil,sandy red soil,yellow soil and purple soil),in 10 counties of southern Jiangxi to analyze the nutrient content.Results showed that the content of N and K of all sampled leaves were excessive while Mg and Zn were insufficient.The content of N,P,K,Ca,Mg,Fe and Zn was significantly different(P0.05) in different types of soils.No significant difference was found in the content of S、Zn、Cu、B and Mo.The leaves collected from sandy red soil had a higher content of P and Fe.The highest content of N was found in leaves from clay red soil,and the occurrence of excessive K and insufficient Mg was rare in this type of soil.Higher P and insufficient Ca were observed in leaves from yellow soil orchards,where leaf Mn was more excessive than the other samples.The leaves on trees in purple soil had the lowest content of N,P and Mg,higher K and Ca,and were usually deficient in Fe if combined with a high soil pH.Leaves of navel orange trees in many orchards of the studied area were seriously deficient in Cu and leaves from a few orchards were deficient in B.The leaf content of S and Mo in all sampled orchards was optimal.