Correlation Analysis on Nutrient Element Contents in Orchard Soils and Sweet Orange Leaves in Southern Jiangxi Province of China

Both soil and leaf samples were collected from 181 red soil orchards of sweet orange grafted on trifoliate orange[Poncirus trifoliata(L.)] rootstocks in Anyuan and Xunwu,the two biggest citrus production counties in southern Jiangxi Province of China,and then analyzed for their nutrient element contents in 2010 and 2011.The aim was to realize relationship between soil and leaf nutrient elements and to provide the possibilities of formulated fertilization based on soil testing in sweet orange orchards in red soil areas.The results showed that the contents of available soil nutrient elements such as nitrogen(N),calcium(Ca),iron(Fe),magnesium(Mg)and zinc(Zn)in orchard soils could reflect,to some extent,the contents of corresponding nutrients in citrus leaves.A significant positive correlation(P 0.05)was found between the contents of available Zn in soils and Zn contents in leaves in Anyuan county in 2010.However,the contents of soil available potassium(K),phosphorus(P),copper(Cu) and boron(B)correlated nonsignificantly with the contents of the corresponding nutrients in leaves.Therefore,formulated fertilization by soil testing is not suitable for sweet orange orchards in red soil areas.It is suggested that formulated fertilization should be mainly based on leaf diagnosis and supplemented by soil testing.