The influence of trigger events on bursts of soil microbial metabolism and N2O production and consumption

气候驱动土壤中发生的生物过程，但在农业氮素管理中，气候描述得很少，也很少被考虑。这是由于土壤氮循环过程的数量和复杂性。在这个建议中，我们研究的作用，气候触发器（解冻的冻土和湿润的干燥土壤）刺激爆发的微生物活动，造成土壤氮素损失。具体来说，这项工作的重点是对无机氮过程，控制硝化和反硝化的时间和相对重要性，在生产N2O排放的影响基板可用性。我的假设是，环境事件触发微生物代谢，通过释放底物作为微生物细胞裂解和溶解土壤有机质的结果。此外，它是微生物代谢作用于这些底物的速率，受土壤温度和含水量的影响，以及碳和氮分布的结构，决定了反硝化作用的位置，强度和产物，因此N2O排放。

Climate drives the biological processes occurring in soil yet is a poorly described and seldom considered part of nitrogen management in agriculture. This is due to the number and complexity of processes involved in the soil N cycle. In this proposal we examine the role of climatic triggers (thawing of frozen soil and wetting of dry soil) in stimulating bursts of microbial activity and causing soil N losses. Specifically this work focuses on the influence substrate availability on inorganic nitrogen processes that control the timing and relative importance of nitrification and denitrification in producing N2O emissions. My hypothesis is that environmental events trigger microbial metabolism through the release of substrates as a result of microbial cell-lysis and solubilization of soil organic matter. Further, it is the rate at which microbial metabolism acts on these substrates, as influenced by soil temperature and water content, and the architecture of carbon and nitrogen distribution which determines the location, intensity, and products of denitrification and therefore N2O emissions.