目的 研究外源性氮和磷对火力楠Michelia macclurei凋落叶分解速率以及分解过程中N、P、K含量变化的影响，为科学合理经营火力楠人工林提供科学依据。方法 在广东云勇林场的火力楠林地上建立4块5 m×5 m的小样地，将凋落叶放入尼龙网袋，并分别喷施N、P或N+P，每隔3个月取样测定凋落叶分解速率和N、P、K含量的变化。结果 施N、P及N+P后凋落叶的分解速率有不同程度的加快，分解24个月后，对照及施N、P和N+P的凋落叶分别分解了52%、66%、78%和73%；对照及施N、P和N+P的凋落叶N含量分别增加了23%、33%、23%和31%，火力楠林地各处理的凋落叶N含量显著大于凋落叶的初始N含量，其中施N和N+P的凋落叶N含量显著大于对照；对照及施N、P和N+P的凋落叶P含量分别增加了7%、18%、59%和46%，且显著大于初始P含量，其中施P和N+P的凋落叶P含量显著大于对照。各处理的凋落叶K含量变化无规律，施 N和N+P的凋落叶K含量显著小于对照，而施P的显著大于对照。对照的凋落叶N和K残留量显著大于其他处理，而施N处理的凋落叶P残留量显著小于对照。结论 施N、P及N+P均可促进火力楠凋落叶的分解，其中施用P肥效果最佳，建议在火力楠林地可适当施用P肥，促进火力楠林的养分循环。
Objective The effects of external nitrogen and phosphorus on leaf litter decomposition rate and changes in N, P, K contents during the decomposition process were studied in a Michelia macclurei woodland to provide a basis for scientific and rational management of M. macclurei plantations.Method Four 5 m×5 m sample plots were set in a M. macclurei woodland of Yunyong forest farm, Guangdong Province. Leaf litters were placed in nylon bags and were sprayed with N, P or N+P respectively. The leaf litter decomposition rate and N, P and K contents were determined every three months.Result The decomposition rate of leaf litter was significantly accelerated by N, P and N+P additions. After 24 months of deconposition, the leaf litter decomposition rates of the control, N, P and N+P additions reached 52%，66%，78% and 73% respectively. N content of leaf litters of the control, N, P and N+P additions increased by 23%，33%，23% and 31% respectively, and was significantly higher than their initial N content, among which N contents of leaf litters treated with N and N+P additions were significantly greater than the control. P content of leaf litters of the control, N, P and N+P additions increased by 7%，18%，59% and 46% respectively, and was significantly higher than their initial P content, among which P content of leaf litters treated with P or N+P additions was significantly greater than the control. K content of leaf litters changed irregularly, and that treated with N or N+P additions was significantly smaller than the control，while that treated with P addition was significantly greater than the control. Remaining amounts of N and K of leaf litter in the control were significantly greater than the other treatments, and remaining amount of P treated with N addition was significantly less than the control.Conclusion N, P and N+P additions can accelerate leaf litter decomposition in M. macclurei woodland, P addition had the best effect. It is suggested that P fertilizer might be added appropriately in M. macclurei woodlands to promote nutrient cycling.