Management effects on the nature of organic matter in agricultural soils

管理对农业土壤有机质性质的影响

• 批准号: RGPIN-2017-05159
• 负责人: Voroney, Paul
• 金额: $ 2.33万
• 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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=634225
• 关键词: Management; effects; nature; organic; matter

Soils cultivated for agriculture are generally depleted in soil organic matter (SOM) relative to their native counterparts (~50% less) so they in the past have been a major source of greenhouse gas emissions. However, agricultural soils also have the potential to be a sink provided they are managed appropriately to sequester C. Adoption of sustainable best management practices to protect and enhance SOM levels is currently actively promoted: reduced frequency and intensity of soil tillage, the planting of complex rotation cropping systems and cover crops to maximize quality and quantity of crop inputs, and maximizing return of crop residues and organic wastes. Despite the central role of SOM in soil functioning, the nature and dynamics of SOM constituents and how they are affected by agricultural management practices are poorly understood. Simply, the effects of these practices on SOM at the molecular level are unknown. Therefore, it is difficult to predict how SOM might respond to current pressures: (i) changes in land management due to agricultural intensification (which is essential for providing foodstuff to world's projected 9 million people), (ii) changes in cropping systems due to plant biomass use for bio-product and biofuel production, or (iii) changes in temperature and precipitation patterns under climate change.

农业土壤的有机质（SOM）通常比原生土壤少50%，因此过去一直是温室气体排放的主要来源。然而，农业土壤也有可能成为一个汇，只要它们得到适当的管理，以螯合C。采用可持续的最佳管理实践来保护和提高土壤有机质水平，目前正在积极推广：减少土壤耕作的频率和强度，种植复杂的轮作系统和覆盖作物，以最大限度地提高作物投入的质量和数量，并最大限度地提高作物残留物和有机废物的回报。尽管有机质在土壤功能中的核心作用，有机质成分的性质和动态，以及它们如何受到农业管理措施的影响知之甚少。简单地说，这些做法在分子水平上对SOM的影响是未知的。因此，很难预测SOM如何应对当前的压力：（i）由于农业集约化（这是为世界预计的900万人口提供粮食所必需的），（ii）由于植物生物量用于生物产品和生物燃料生产，或（iii）在气候变化下温度和降水模式的变化，在种植系统的变化土地管理的变化。