Characteristics and Coupling Relationship of Soil Organic Carbon and Total Nitrogen in Different Types of Phyllostachys pubescens Stands

The characteristics of soil organic carbon and total nitrogen of three typical Phyllostachys edulis forests(P.edulis pure forest,P.edulis and broad-leaved tree mixed stands and P.edulis and Cunninghamia lanceolata mixed forest) in Anfu,Jiangxi province were studied by regarded Schima superba forest,Cunninghamia lanceolata forest and abandoned land as contrasts.The results showed that the SOC(soil organic carbon) storage and SOCD(soil organic carbon density) both are differed significantly with forest type and soil layer.SOC ranked as the following: Ⅰ(13.12 g/kg)Ⅲ(12.42 g/kg)Ⅱ(11.47 g/kg)Ⅴ(10.57 g/kg)Ⅳ(8.53 g/kg)Ⅵ(7.45 g/kg),and there was remarkable difference among the stands.Meanwhile,there was remarkable difference in SOCD among the stands,with a rank ofⅠ(8.81 kg/m2)Ⅴ(7.69 kg/m2)Ⅲ(7.51 kg/m2)Ⅳ(7.38 kg/m2)Ⅱ(5.94 kg/m2)Ⅴ(5.70 kg/m2).There was a negative correlation between the SOC and the depth of soil.The SOC storage in 0-40 cm accounted for more than 70% of the total.The index of C/N was different in different forest type,and was ranged 11 to 15.The mixed forest index of C/N was higher than the pure forest.There was a great significant correlation between the SOC and the total nitrogen.It can be simulated well by model of polynomial.