Effect of magnesium (Mg) application in Satsuma Mandarin orchard with Mg nutrient deficiency

【Objective】The goal of this research was to explore the mitigation solutions for magnesium(Mg) nutrition deficiency in Satsuma Mandarin orchard.【Method】The experiment was carried out in a citrus orchard with Mg deficient soil and low p H. Two treatments were designed to study the effect of Mg application in Satsuma Mandarin orchard. The concentration of Mg and the content of SPAD,starch and soluble sugar in citrus leaves and fruits were measured.【Result】The results showed that Mg content in leaves decreased with the ageing of leaves. Compared with control(CK),the application of Mg fertilizer significantly increased the content of Mg and SPAD in leaves and the content of soluble sugar in fruits.However,a lower content of starch was observed after the application of Mg. The content of Mg in leaves was significantly positive correlated with the content of SPAD and the content of Mg in fruits.【Conclusion】Based on the results,it could be concluded that the application of Mg fertilizer in soil combined with foliar spray can alleviate the leaf etiolation of Satsuma mandarin in the late fruit expanding period due to the increase of Mg content in leaves,enhancing the transport of Mg to fruit and the increase of Mg content and soluble sugar content in fruit.