Tillage and cropping effects on the fate of crop derived-c and n and turnover of soil organic matter

耕作和耕作对作物衍生碳和氮的命运以及土壤有机质周转的影响

• 批准号: 2280-2010
• 负责人: Voroney, Paul
• 金额: $ 1.82万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507627
• 关键词: Tillage; cropping; effects; fate; crop

Two-thirds of the terrestrial C is stored as soil organic matter (SOM) in agricultural, forest and grassland soils, therefore it is a primary storehouse of global C and changes in the dynamics of SOM can influence global levels of atmospheric carbon dioxide (CO2). SOM is also critical for plant and animal life because of it modifies soil physical, chemical and biological properties, including nutrient and water retention, erosion resistance, and soil fertility. Despite this central role, the nature and dynamics of SOM as affected by land-use change or global warming are poorly understood - it is considered to be the most complex mixture on earth. Agricultural ecosystems account for 11% of the land area and management practices directly affect SOM formation and turnover. Recently these soils have become a major research focus because of the potential for SOM to mitigate climate change: the soils have lost 30-50% of their original SOM but could be managed to be a major global reservoir for atmospheric CO2 where plant C is sequestered as SOM that is hundreds to thousands of years old. My research program studies how farming practices and soil properties affect SOM constituents and is critical for devising strategies for sequestering C. The proposed research will be conducted on soil and crop samples collected at a long-term field site located at Delhi, ON. These field plots were established in 1988 on a site in tobacco-fall rye rotation since 1933. The soils are loamy sand, allowing study of SOM constituents free of the confounding affects of clay. It includes three cropping systems (continuous corn, a soybean-wheat rotation and a tobacco-rye rotation), under two tillage regimes, CT using mouldboard plough-disc tillage and NT. The goal is to identify changes in the quantity and composition of SOM resulting from a shift in cropping sequence and tillage from the previous tobacco-rye CT rotation. Since measurable changes in SOM pools occur slowly, the fact that this site has been in place for ~20 yr is invaluable. It believed to be the only long-term site in the world containing 14C- and 15N-labelled crop residues and allowing measurements of delta 13C because of the switch from C3 (tobacco-rye) to C4 (corn) species.

三分之二的陆地C作为农业，森林和草原土壤中的土壤有机物（SOM）存储，因此它是全球C的主要仓库，SOM动力学的变化会影响全球大气二氧化碳水平（CO2（CO2） ）。 SOM对于动植物的生命也至关重要，因为它可以修饰土壤的物理，化学和生物学特性，包括养分和保留水，耐侵蚀性和土壤肥力。尽管有这种核心作用，但对土地利用变化或全球变暖影响的SOM的性质和动力学知之甚少 - 它被认为是地球上最复杂的混合物。农业生态系统占土地面积和管理实践的11％，直接影响SOM形成和营业额。最近，由于SOM有可能减轻气候变化的可能性，这些土壤已成为主要的研究重点：土壤损失了其原始SOM的30-50％，但可以设法成为大气CO2的主要全球储层，其中植物C被隔离了如数百至数千年的历史。我的研究计划研究了农业实践和土壤特性如何影响SOM成分，对于制定隔离的策略至关重要C。拟议的研究将在安大略省德里的长期现场收集的土壤和农作物样品上进行。自1933年以来，这些田间地块于1988年建立在烟草 - 弗尔黑麦旋转的地点上。土壤是壤土的壤土，可以研究没有粘土混杂影响的SOM成分。它包括三个种植系统（连续玉米，一个大豆麦旋转和烟草旋转），在两个耕作方案下，使用mouldboard Plough-Disc耕作和NT。目的是确定由于先前的烟草rye ct旋转而导致的植物序列和耕作变化所产生的质量和组成的变化。 由于SOM池的可测量变化发生缓慢，因此该地点已经存在约20年的事实是无价的。据信它是世界上唯一包含14c和15n标记的作物残基的长期地点，并且由于从C3（烟草）转换为C4（玉米）物种，因此可以测量三角洲13C。