摘要:为了解亚热带森林土壤碳氮及酶活性对气候变暖的响应，以武夷山不同海拔的三种典型森林群落土壤为研究对象，采用把高海拔土柱置换到低海拔的方式模拟增温，探究模拟增温对土壤碳、氮、磷循环相关酶活性及土壤理化性质的影响。结果表明：土柱置换后海拔梯度上土壤温度平均增加2℃。土柱置换模拟增温导致高海拔（1400 m）土壤有机碳下降幅度最大；不同海拔土壤铵态氮、硝态氮、微生物生物量碳均呈下降趋势，仅高海拔达到显著水平。土柱置换对各海拔土壤水解酶活性影响较大，而对氧化酶活性没有显著影响。相反，土柱置换增温增加了各海拔土壤归一化酶活性，且高海拔土壤归一化酶活性对增温的响应程度比低海拔更大。冗余分析结果发现，土壤有机碳、可溶性有机碳、土壤温度和含水率是影响土壤酶活性变化最重要的因子。本研究表明模拟增温对高海拔土壤碳氮循环过程影响较大，其机制主要是通过提高微生物活性和分泌酶的能力来影响土壤碳氮循环过程。



Abstract:To understand how soil carbon and nitrogen as well as enzyme activities response to climate in subtropical forests. Here, three typical forest community soils at different elevations of Wuyi Mountain were selected. The effects of stimulated warming on soil carbon (C), nitrogen (N), phosphorus (P) cycling related enzyme activity and physicochemical characteristics of soils were studied through translocating high altitude soil core to low altitude one. The results showed that the soil temperature increased by 2℃ on altitude gradient. The soil-translocation experiment showed that soil organic carbon (SOC) decreased most at high altitude (1400 m). The soil ammonium, nitrate, microbial biomass showed a decreasing trend at different altitudes, but the significant effect was observed at high altitudes alone. The elevation gradient and warming treatment were found to have a significant effect on soil hydrolase at all elevations in the soil-translocation experiment, but had no significant effect on peroxidase and phenol oxidase. On the contrary, the soil-translocation experiment was proved to have increases on soil specific enzyme activity at all elevations, and the soil specific enzyme activity at high elevations was more sensitive to temperature increase than that at low elevations. Redundancy analysis (RDA) showed that soil organic carbon, dissolved organic carbon, soil temperature and moisture content were the most important factors affecting the change of soil enzyme activity. In conclusion, this study showed that the stimulating warming had a greater impact on the carbon and nitrogen cycling process in soil at high elevations, mainly by improving microbial activity and enzyme secretion ability.





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