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

触发事件对土壤微生物代谢爆发和N2O产生和消耗的影响

• 批准号: RGPIN-2015-03746
• 负责人: Burton, David
• 金额: $ 1.97万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=646593
• 关键词: influence; trigger; events; bursts; soil

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.***The goal of my research is to understand the impacts of climate and climate change on soil N transformations and nitrogen losses. The specific objective of this proposal is firstly (PhD1) to examine the mechanisms resulting in N2O bursts in response to thawing and wetting triggers under controlled environment conditions and secondly (PhD 2) to examine the production and consumption of N2O in soil profiles in response to thawing and wetting triggers under field conditions.***This research takes advantage of recent technological developments that allow high frequency measurement of the isotopomeric composition of N2O emissions to determine the source of N2O during trigger events. Measurements of N2O production will be coupled with continuous measurement of soil water and temperature to provide a dynamic picture of how the physical effects of trigger events are translated into shifts in microbial metabolism. ***This research is innovative in that it uses high frequency measurement of concentration and isotopomeric composition of N2O to study the nature of microbial metabolism associated with environmental events. The use of 15N site preference of N2O will distinguish between nitrification and denitrification as sources of N2O during these events as well as the consumption of N2O by denitrification. ***This research will provide insight into the potential impacts of climate change on soil microbial processes. A better understanding of how agricultural management impacts N2O emissions associated with thawing and wetting events. This is important for developing strategies to sustain soil fertility and reduce greenhouse gas emissions from agriculture, reduce impacts on water quality and increase the profitability and sustainability of agriculture.

气候驱动着土壤中发生的生物过程，但描述的很少，很少被认为是农业中氮管理的一部分。这是由于土壤n周期中涉及的过程的数量和复杂性。在此提案中，我们研究了气候触发因素（冻结土壤和干燥土壤润湿）在刺激微生物活性爆发中的作用，并导致土壤N损失。具体而言，这项工作着重于底物对无机氮过程的影响，这些过程控制了硝化和硝化在产生N2O排放中的时机和相对重要性。我的假设是，环境事件通过微生物细胞溶解酶和土壤有机物的溶解而引发微生物代谢。此外，由于土壤温度和水含量的影响，微生物代谢作用于这些底物的速率，以及决定了硝化剂的位置，强度和产物的碳和氮分布的结构，因此N2O的排放。该提案的具体目标首先是（PHD1）检查导致N2O爆发的机制，以响应在受控的环境条件下解冻和润湿触发器，其次（PHD 2）（PHD 2）检查土壤中N2O的生产和消费，以响应于杂种和润湿性的范围，以使其在现场的范围中采取了高度的范围。 N2O排放确定触发事件期间N2O的来源。 N2O产生的测量将与土壤水和温度的连续测量结合在一起，以提供动态图片，说明如何将触发事件的物理效应转化为微生物代谢的变化。 ***这项研究具有创新性，因为它使用了N2O的浓度和同位素组成的高频测量来研究与环境事件相关的微生物代谢的性质。 N2O的15N站点偏好将在这些事件期间将硝化和反硝化作为N2O的来源以及通过反硝化消耗N2O的来源。 ***这项研究将洞悉气候变化对土壤微生物过程的潜在影响。更好地理解农业管理如何影响与解冻和润湿事件相关的N2O排放。这对于制定维持土壤生育能力并减少农业中温室气体排放的策略很重要，降低对水质的影响并提高农业的盈利能力和可持续性。