Forest Litter Decomposition Zone In Sai Han Province Nature Reserve (Interim) And Nutrient Dynamic Characteristics

Litter, which is a key part of forest ecosystem, is not merely maintaining stabilization function of nutrient cycling, energy flow, structure and function of forest ecosystem, but also benefits for continuously improving the level of soil fertility. Therefore, it will be of great importance in stability and balance of forest ecosystem by searching litter in different secondary forest.The research was conducted in Betula platyphylla and Pobulus davidiana secondary forest located in Saihanwula national nature reserve zone. The result of how dynamic change of litter-fall, dynamic change of nutrient content and environmental factors effect litter decomposition in the period of medium litter decomposition shown as follows:(1) According to observation of April to October of 2015, The monthly dynamic changes of litter decomposition of Betula platyphylla and Pobulus davidiana secondary forest shows model of unimodal curve, all behaves as lowest in July, highest in September.(2) Litter decomposition of Betula platyphylla and Pobulus davidiana secondary forest is very slowly, the quality residual rate (42.21%) and weight loss rate (0.66%) of Betula platyphylla secondary forest are more than Pobulus davidiana’s the quality residual rate (33.12%) and weight loss rate (0.50%).(3) Two types of secondary forest’s quantity of these four nutrient from better to less was:Pobulus davidiana secondary forest:OCTK>TN>TP; Betula platyphylla secondary forest:OCTN>TK>TP.(4) According to observation of April to October, While correlation had increased between the weight loss ratio of Pobulus davidiana secondary forest and water content, temperature in 5cm of soil. While correlation had decreased between the weight loss ratio of Betula platyphylla secondary forest and water content, temperature in 5cm of soil. The weight loss ratio of Betula platyphylla secondary forest also related with temperature in 5cm of soil, but not significantly.(5) The soil enzyme activity of the place where Betula platyphylla and Pobulus davidiana secondary forest set mesh bag of litter are both higher than where the unmanaged sample plots did not set mesh bag of litter. Correlation between weight loss ratio of two kinds of sample plots and catalase decreased, but correlation between weight loss ratio of two kinds of sample plots and invertase increased. The quantity of MBC and MBN of the sample plot of Betula platyphylla secondary forest are both higher than Pobulus davidiana. Correlation had decreased between weight loss ratio of Pobulus davidiana secondary forest sample plot and the quantity of MBC and MBN; while Betula platyphylla’s increased. Correlation had decreased between the quantity of C and catalase. Correlation had decreased between the quantity of Pand invertase.