Gross nitrogen cycling processes and nitrous oxide emissions in cultivated and non-cultivated hummocky soil landscapes

耕作和非耕作丘状土壤景观中的总氮循环过程和一氧化二氮排放

• 批准号: 329968-2006
• 负责人: BedardHaughn, Angela
• 金额: $ 2.91万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: University Faculty Award
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=366281
• 关键词: Gross; nitrogen; cycling; processes; nitrous

To determine the best strategy for long-term management of agricultural landscapes in the Canadian Prairies, we need to improve our understanding of N-cycling processes and those factors controlling them. The proposed research program will examine the relationship between land management practices and N-cycling processes of agricultural and environmental significance. The emphasis will be on those processes that produce inorganic N (i.e., mineralization and nitrification) and those that emit nitrous oxide (i.e., denitrification and nitrification). Nitrous oxide is a greenhouse gas that has 300 times the global warming potential of carbon dioxide and in Canada, agriculture accounts for up to 70% of human-induced nitrous oxide emissions. There is particular need for improved understanding of gross N-producing processes, which refers to the total amount of inorganic N produced from the organic N pool in a given time period, and how these relate to N-emitting processes. To date there have been few studies considering gross N production at the landscape scale and none known of in the Canadian Prairies. To address this gap in N-cycling knowledge, the proposed research program will compare N production and nitrous oxide emissions under cultivated and non-cultivated land uses in the Brown, Dark Brown, and Black soil zones of Saskatchewan. Stable 15N isotope techniques will be used to (1) quantify management effects on gross mineralization and nitrification rates in hummocky till landscapes and (2) estimate the relative significance of nitrification and denitrification to nitrous oxide emissions.

为了确定加拿大大草原农业景观长期管理的最佳策略，我们需要加深对氮循环过程及其控制因素的了解。拟议的研究计划将研究土地管理实践与具有农业和环境意义的氮循环过程之间的关系。重点是那些产生无机氮的过程（即矿化和硝化）和排放一氧化二氮的过程（即反硝化和硝化）。一氧化二氮是一种温室气体，其全球变暖潜力是二氧化碳的 300 倍，在加拿大，农业排放的一氧化二氮占人类引起的一氧化二氮排放量的 70%。特别需要加深对总氮生产过程的理解，总氮生产过程是指在给定时间段内从有机氮库中产生的无机氮总量，以及它们与氮排放过程的关系。迄今为止，很少有研究考虑景观尺度的总氮产量，而且在加拿大大草原上也没有研究。为了解决氮循环知识方面的这一差距，拟议的研究计划将比较萨斯喀彻温省棕色、深棕色和黑土地区耕地和非耕地用途下的氮产量和一氧化二氮排放量。稳定 15N 同位素技术将用于 (1) 量化对丘状耕作景观中总矿化和硝化速率的管理影响，以及 (2) 估计硝化和反硝化对一氧化二氮排放的相对重要性。