摘要
开展亚高山针叶林典型林地土壤有效氮和微生物特性对气候变化的响应研究,对预测未来气候变化背景下亚高山针叶林生态系统C、N的源/汇功能具有重要意义。该文采用红外辐射加热器模拟增温结合外施氮肥的方法,研究了川西亚高山针叶林下土壤化学特性、有效氮含量以及微生物生物量对夜间增温和施氮的短期响应。结果表明:在模拟增温试验期间(2009年4月–2010年4月),空气平均温度和5cm土壤平均温度分别比对照提高了1.93和4.19℃,增温幅度分别以夏季和冬季最为显著。增温对土壤pH值、有机碳、全氮和微生物生物量无显著影响。增温在试验前期降低了土壤NH4+-N含量,增加了NO3–-N含量,其影响程度随着增温时间的延长而下降。施氮显著增加了有效氮和微生物生物量氮,降低了土壤pH值,使土壤表现出明显的酸化现象。与单独的增温和施氮处理相比,增温和施氮联合处理对林下土壤的有效氮和微生物特性有显著的交互作用,显著增加了土壤的有机碳、有效氮及土壤微生物生物量氮含量,并导致土壤进一步酸化。结果说明,川西亚高山针叶林的土壤有效氮和微生物特性对土壤氮素状况的变化反应敏感,而林下土壤有效氮和微生物特性对单独的温度升高表现出一定的适应性,但更对增温和施氮双因素结合处理反应敏感且表现出不同的响应方式。因此,该区域在未来全球变化下的氮沉降状况及气候变化的多因素协同效应值得长期深入的探讨。
Aims The subalpine coniferous forest in eastern Qinghai-Tibet Plateau provides a natural laboratory for studying effects of climate change on terrestrial ecosystems.Research on responses of soil nitrogen availability and microbial properties to experimental warming and nitrogen addition can provide insights into their C resource/sink function under future climates.Methods We used an infrared heater combined with nitrogen addition to determine the short-term influences of two level of air temperature(ambient and warmed) and nitrogen addition(0 and 25 g N·m–2·a–1) on soil chemical properties,available nitrogen and microbial biomass.Important findings The warming manipulation increased mean air temperature and soil temperature at 5-cm depth by 1.93 and 4.19 °C,respectively,and the temperature increment was larger in summer and winter.Warming generally had no significant effects on soil pH,organic C,total N and microbial biomass,but it decreased soil ammonium nitrogen and increased nitrate nitrogen content.The warming effect was reduced with time.Nitrogen addition significantly increased available nitrogen and microbial biomass,but decreased soil pH,acidifying the soil.Compared with individually warming or adding nitrogen,the interaction of the two factors significantly increased organic C,available N and microbial biomass.Results suggest that soil nitrogen availability and microbial properties were sensitive to N status.Although soil nitrogen availability and microbial properties may adapt to temperature increase to some extent,the interaction of the warming and nitrogen addition significantly changed their response mode.Therefore,nitrogen deposition and multiple factors have interacting effects on the ecosystem and these should be further studied in this region.
出处
《植物生态学报》
CAS
CSCD
北大核心
2010年第11期1254-1264,共11页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(30800165和30800161)
中国科学院知识创新工程重要方向项目(KSCX2-YW-Z1023)
中国科学院"西部之光"人才计划项目(08C2031100)
中国科学院成都生物研究所领域前沿项目(08B2031和Y0B2021100)共同资助
关键词
有效氮
微生物生物量
施氮
亚高山针叶林
增温
available nitrogen
microbial biomass
nitrogen addition
subalpine forest
warming