中文摘要：

研究林分改造实施3年后不同改造模式马占相思林凋落物和土壤的持水性能、降雨集中期内地表径流量、泥沙量及氮、磷径流流失状况。改造实施当年（2008年）马占相思林林龄为16年,改造模式包括均匀疏伐30%原有马占相思后套种乡土阔叶树（模式Ⅰ）、均匀疏伐60%原有马占相思后套种乡土阔叶树（模式Ⅱ）、未改造的原有相思林（对照,CK）。结果表明：（1）改造模式Ⅰ的凋落物现存量和最大持水量均显著高于改造模式Ⅱ和CK;（2）改造模式Ⅰ土壤（0-20cm和20-40cm土层）总孔隙度、模式Ⅱ的0-20cm层土壤总孔隙度显著低于CK,模式I、Ⅱ土壤最大持水量显著低于CK;（3）模式I、Ⅱ的累积径流量和累积泥沙流失量均显著高于CK,但模式Ⅰ、Ⅱ间无显著差异;（4）监测期内改造模式Ⅰ、Ⅱ的径流水样总氮、总磷平均浓度与CK无显著差异,但总氮、总磷累积流失量均显著高于CK。所以,改造3年后,林地氮磷流失量相对于未改造林分显著增加,而不同改造模式的水土和养分保持效能无显著差异。

英文摘要：

Water holding capacity of forest litter, soil water holding capacity, and surface runoff yield, sediment, nitrogen（N） and phosphorus（P） losses via runoff water during the rainy season were studied in Acacia mangium plantations treated 3 years ago with different methods. The plantations were 16 years old in the year of treatment（2008）. The forest stand treatment methods were evenly removing 30% of A. mangium trees followed by planting native broadleaved trees in the canopy gaps（mode Ⅰ）, and evenly removing 60% of A. mangium trees followed by planting native broadleaved trees in the gaps （mode Ⅱ ）. The un-thinned plantation served as control（CK）. Results showed that mode Ⅰ had significantly higher forest litter biomass and maximum water holding capacity than mode Ⅱ and CK. Mode Ⅰ andⅡ had significantly lower soil pore volume and water holding capacity than CK. Modes Ⅰ and Ⅱ had significantly higher accumulative surface runoff yield and accumulative sediment amount than CK, but modes Ⅰ and Ⅱ were not significantly different. No significant differences were observed in the mean concentrations of total N or total P between modes Ⅰ, Ⅱ and CK, but modes Ⅰ and Ⅱ had significantly higher accumulative total N and total P losses than CK. We concluded that three years after the treatments, surface losses of N and P unfortunately increased, and treatment methods did not exhibit significant differences in water, soil and nutrient preserving capacities.