摘要:火干扰是通过改变土壤理化性质而影响土壤生态系统功能的重要因素之一。探讨火干扰强度对不同森林类型下土壤理化性质的影响，为利用火干扰促进林分更新及经营提供理论指导。2014年在湖南省株洲市和湘潭市4种次生林（枫香次生林、马尾松-木荷混交林、杉木-木荷混交林及檫木-杉木混交林）内设置16块20 m×20 m样地进行试验，研究了火干扰强度（对照、低强度、中强度、高强度火烧）和林分类型对土壤容重（BD）、土壤斥水性（SWR）、有机质（SOM）、pH、全氮（TN）、全磷（TP）和全钾（TK）的影响。通过描述性统计分析、单因素方差分析和Fisher LSD检验研究各土壤性质在同一林分不同火干扰间，以及同一火干扰下不同林分间的显著性差异和变化趋势（P<0.05）。研究发现BD、SWR、pH、TK都随火强度的增大呈上升的趋势，而SOM、TP随火强度增大而减少，TN则随火强度增大没有规律性变化。在同一林分内与对照组相比，低强度火烧对BD、SWR、pH和SOM的影响不显著，中强度有一定影响，而高强度火烧影响显著；而TN、TP、TK在火烧前后均无显著性差异。火干扰后，TN和TP在同一火强度下不同林分间均存在显著性差异（P<0.05），而BD、pH值和TP在同一林分内不同火强度间均存在显著性差异（P<0.05）。BD、SOM、pH、TK在枫香次生林内普遍显著大于其他林分。结果说明火干扰强度和林分类型在影响土壤理化性质方面起着重要作用。高强度火干扰对土壤性质影响最大，枫香次生林中土壤理化性质与其他混交林相比普遍存在显著性差异。BD、pH和TP受火强度影响显著，BD、SOM、pH、TN、TK和TP受林分类型影响显著。



Abstract:Fire disturbance is one of the most important factors that influences the ecosystem function of soil by changing its physical and chemical properties. To provide theoretical guidance for forest regeneration and management using fire disturbance, this study explored the influence of fire intensity on soil physical and chemical properties in different forest types. The effects of fire intensity (control, low, moderate, and high-intensity fire) and forest types on bulk density (BD), soil water repellency (SWR), soil organic matter (SOM), pH, total nitrogen (TN), total phosphorus (TP), and total potassium (TK) were determined in a field-scale experiment on 16 plots (20 m×20 m) in four secondary forests (Liquidambar formosana, Pinus massoniana-Schima superba, Cunninghamia lanceolata-Schima superba, and Sassafras tzumu-Cunninghamia lanceolata) in Zhuzhou and Xiangtan, Hunan Province, southern China, in 2014. The differences and trends in change of soil properties among the different fire-disturbance levels in the same forest and among forest types under the same fire-disturbance level were analyzed using descriptive statistical analyses, one-way ANOVA, and Fisher LSD test (P<0.05). BD, SWR, pH, and TK increased with increase in fire intensity, whereas SOM and TP decreased and TN was not altered with increasing fire intensity. Compared with the control group in the same stand, the effects of low-intensity fire on BD, SWR, pH, and SOM were not significant; however, moderate-intensity fire had some effects, and the effects of high-intensity fire were significant. Nevertheless, no significant differences were observed among TN, TP, and TK pre- and post-fire. There were significant differences in TN and TP between the different forest types after the same fire disturbance, whereas there were significant differences in BD, pH, and TP among fire intensities in the same forest type (P<0.05). BD, SOM, pH, and TK in secondary forests of L. formosana were significantly higher than those in the other forest types. The results indicated that fire disturbances and forest types played significant roles in altering soil physical and chemical properties. High-intensity fire had the greatest effects on soil properties. There were significant differences in soil properties between L. formosana and the other three mixed forests. BD, pH, and TP were significantly affected by fire intensity. BD, SOM, pH, TN, TK, and TP were significantly affected by forest types.





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