Objective To study the effects of nitrogen and phosphorus additions on leaf litter decomposition, nutrient dynamics and soil biochemical characteristics during the decomposition process in a Acacia mangium plantation in order to understand the mechanism of influence of nitrogen and phosphorus on leaf litter decomposition of A. mangium and forest soil nutrient management.

Method Leaf litter decomposition of the A. mangium plantation in Yunyong Forest Farm was investigated using litter bag method. N and P additions were designed in four treatments:the control, N addition (N 10 g·m^-2), P addition (P 5g·m^-2), and N+P addition (N 10g·m^-2+P 5g·m^-2). It was sampled in a three-month interval and then the remaining leaf litter and N, P, K contents were analyzed.

Result The N, P and N+P additions improved leaf litter decomposition. The N content of leaf litter with the four treatments remained stable. The P content of leaf litter with P and N+P additions tended to increase and were greater than their initial value during litter decomposition process. The K content of leaf litter with the four treatments changed irregularly. The N, P and N+P additions significantly increased soil organic matter and total N contents and improved activities of soil urease, acid phosphatase and catalase.

Conclusion N, P and N+P additions accelerated leaf litter decomposition of the A. mangium, which improved the nutrient cycling of A. mangium plantation.