黄土高原旱作农田净综合增温潜势对降水变化的响应机制

项目名称： 黄土高原旱作农田净综合增温潜势对降水变化的响应机制

项目编号： No.31270484

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 王俊

作者单位： 西北大学

项目金额： 77万元

中文摘要： 降水事件对旱作农田土壤温室气体排放过程具有显著但短暂的激发效应，这可能进一步影响到长时间尺度的生态系统净综合增温潜势。项目拟以黄土高原旱作冬小麦农田为例，基于人工控制降水系列试验和长期定位试验，通过改变降水量、强度、频率和季节分布，在田间系统观测的基础上，分析旱作农田土壤温室气体(CO2、N2O、CH4)对降水变化的动态响应规律，确定降水激发效应对农田净综合增温潜势的贡献；通过分析降水前后土壤不同形态碳/氮浓度、微生物活性和群落结构变化，阐明"底物供给"和"微生物胁迫"两种机制的相对重要性及其微生物功能响应机理；并在此基础上，通过研究不同降水模式下的根系呼吸和作物产量形成过程，揭示作物产量-水氮利用效率-净综合增温潜势之间的耦合关系。项目预期结果可以深化对旱作农田生态系统碳氮循环过程及其与气候变化交互作用机制的理解，并为黄土高原地区农田固碳减排管理实践提供重要的理论支撑。

中文关键词： 温室气体排放；综合增温潜势；降水变化；响应机制；旱作农田

英文摘要： Precipitation event has a short priming effect on greenhouse gas (CO2, N2O, and CH4) (GHG) emissions under dryland cropping systems which may affect the long-term net global warming potential (GWP) in the arid and semiarid areas. In this project, we will quantify the effects of precipitation intensity, frequency, and seasonal and annual distribution on GHG emissions and net GWP under a winter wheat-fallow cropping system by using the rainfall-manipulated technique in the Loess Plateau. The relative importance of "substrate supply" and "microbial stress" mechanisms in responding of GHG emissions to precipitation will be evaluated by analyzing changes in soil carbon and nitrogen fractions, enzyme activity, microbial biomass and activity, and microbial community structure during soil drying-wetting cycles due to precipitation events. The response of root respiration and crop production to precipitation will also be measured to elucidate the trade-offs between crop yield formation, water and nitrogen use and net GWP as being stimulated by precipitation events under dryland cropping systems. The results will provide a better understanding of carbon and nitrogen cycles in the agroecosystem and their interaction with climate change in the arid and semiarid areas. The experiment will also provide opportunity to develop

英文关键词： greenhouse gas emission；global warming potential；precipitation change；responding mechanism；dryland cropping system