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: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=473573
• 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.

陆地碳的三分之二以土壤有机质（SOM）形式储存在农业、森林和草原土壤中，因此它是全球碳的主要仓库，SOM动态的变化可以影响全球大气二氧化碳（CO2）的水平。 SOM 对植物和动物的生命也至关重要，因为它可以改变土壤的物理、化学和生物特性，包括养分和保水性、抗侵蚀性和土壤肥力。尽管发挥着核心作用，但人们对 SOM 受土地利用变化或全球变暖影响的性质和动态知之甚少——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的11%，管理实践直接影响SOM的形成和周转。最近，由于 SOM 缓解气候变化的潜力，这些土壤已成为主要研究焦点：土壤已经失去了 30-50% 的原始 SOM，但可以成为全球大气 CO2 的主要储存库，其中植物 C 被封存为数百至数千年历史的 SOM。我的研究项目研究农业实践和土壤特性如何影响 SOM 成分，这对于制定碳隔离策略至关重要。拟议的研究将对在安大略省德里的一个长期田间采集的土壤和作物样本进行。这些田间样地于 1988 年在自 1933 年以来一直进行烟草-秋季黑麦轮作的地点建立。土壤为壤质沙土，允许研究 SOM 成分，不受粘土的混杂影响。它包括三种耕作系统（玉米连作、大豆-小麦轮作和烟草-黑麦轮作），采用两种耕作方式：使用犁盘式耕作的 CT 耕作法和 NT 耕作法。目标是确定由于之前的烟草-黑麦 CT 轮作的种植顺序和耕作方式的变化而导致的 SOM 数量和成分的变化。 由于 SOM 池的可测量变化发生得很慢，因此该站点已经存在约 20 年的事实是无价的。它被认为是世界上唯一长期含有 14C 和 15N 标记作物残留物并允许测量 delta 13C 的地点，因为从 C3（烟草黑麦）物种转变为 C4（玉米）物种。