Intra-annual dynamics of soil conservation value in forest ecosystem

Based on observational data,the intra-annual dynamics of soil conservation values in five forest ecosystems were studied by means of daily rainfall erosive agent model and the Universal Soil Loss Equation.The results show that the soil conservation values of seasonal rainforest,secondary forest,rubber plantation,broad-leaved korean pine forest and secondary birch forest are 570.29,347.87,174.65,14.31 and 8.76 yuan·hm-2·a-1,respectively.The soil conservation values are characterized with an uneven distribution in a year and the soil conservation value produced from May to October takes up 80% of the annual total value.In the composition of soil conservation value in three forest ecosystems in Xishuangbanna,the value of soil nutrition conservation accounts for more than 60%.In two forest ecosystems in Changbaishan,the composition of soil conservation value is different and the value of decreasing soil deposit is predominated in broad-leaved korean pine forest,while the value of soil nutrition conservation is predominated in secondary birch forest.The value of reducing land disuse accounts for less than 10% of the total soil conservation value.