Decomposition Rate of Litter and Dynamic Change of Nutrients in Different Stands in Coal Mining Subsidence Area

The litter samples of Salix psammophila,Populus simonii Carr and Salix psammophila-Populus simonii Carr mixed forest in the subsidence area of Lijiata coal mine in Shenfu Coalfield were collected and used as the materials in a field litter decomposition experiment with decomposition bags, the effects of litter sources and soil type on decomposition rate and dynamic characteristics of nutrient release of litter were investigated, in order to provide reference for regional ecological restoration.The results showed that the k value of Salix psammophila litter reached the peak of 0.180 at 240 days, and the k value of mixed litter increased to 0.125 at 180 days; k value of litter in Populus simonii Carr forest reached a peak of 0.124 at 240 days.At the same time, the total nitrogen content of litter was Salix psammophila forest＞mixed litter＞Populus simonii Carr forest.Organic carbon content from high to low was Salix psammophila forest＞mixed litter＞Populus simonii Carr forest.The total phosphorus content of Salix psammophila litter reached its peak at 60 days(0.979 g·kg^-1),and its C/N was 57.86-75.18.That was, 60 days＞CK＞120 days＞180 days, reaching the maximum value（78.88） in 60 days and the minimum value（57.86） in 180 days.The C/N ratio of mixed litter was 72.89-92.01,which reached the peak at 120 days.The litter of Populus simonii reached the lowest value of 77.22 in 180 days.The litter of Salix psammophila forest in coal mining subsidence area had higher decomposition rate and ability to return to soil nutrients, which provided reference for regional ecological restoration.