典型草原氨氧化微生物及土壤氮素矿化对放牧和水氮有效性的响应

项目名称： 典型草原氨氧化微生物及土壤氮素矿化对放牧和水氮有效性的响应

项目编号： No.31300386

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 陈清

作者单位： 天津师范大学

项目金额： 22万元

中文摘要： 氮沉降增加和降水分布模式变化成为全球性环境问题显著改变内蒙古典型草原生态系统生物地球化学过程。过度放牧是引起内蒙古典型草原退化的重要原因。研究放牧、水分和氮素交互作用对该系统的影响，对于理解该系统对环境变化的响应、内蒙古草原退化机理有重要意义。2005-2011年，申请人对放牧、水氮及其交互作用对内蒙古典型草原净初级生产力的影响做了初步研究。根据此研究结果得出新的实验假设，即水分有效性高时，与中度放牧相比，过度放牧加速土壤氮素转化和输出，造成营养物质恶性循环。为进一步验证此实验假设，本项目以为期7年的放牧、水氮三因子长期定位田间试验为研究基地，利用分子生物学技术探究放牧、水氮及其交互作用对氨氧化微生物数量和结构组成以及土壤氮素矿化的影响。进而深入理解水氮资源变化条件下，过度放牧对草原土壤氮素循环的影响机制。

中文关键词： 氮素；水分；放牧；矿化；氨氧化微生物

英文摘要： Widespread nitrogen enrichment and precipitation distribution change were the global environmental problems which had a profound effect on grassland ecosystem in Inner Mongolian steppe. Overgrazing was one of main reason to led to the degradation of Inner Mongolian grasslands. Studies on the interactive effects of graze, water and nitrogen enrichment on this ecosystem are important for understanding the ecosystems response to global climate change and the theroy of degrade grassland restoration. During 2005-2011, we preliminary explore the response of net primary production to nitrogen, water and graze in the Inner Mongolian steppe. We suppose that compare with morderately grzaed site,overgraze made faster N turnover, with associated output, could act as a positive feedback to drain soil nutrients from overgrazed sites even faster. For further prove this hypothesis, we do the research on this 7 years old experiment field which include graze, water and nitrogen three factors. We explore the interactive effect of graze, water and nitrogen on ammonia-oxidizing microorganism and soil nitrogen mineralization. This research will help to further understand the soil N cycling as influenced by overgrazing under environment change in Inner Mongolian steppe.

英文关键词： nitrogen；water；graze；mineralization；ammonia- oxidizing microorganism