Biotic controls on the residence time of soil carbon and nitrogen: new understanding from stable isotope probing and optimization modeling

对土壤碳和氮停留时间的生物控制：稳定同位素探测和优化模型的新认识

• 批准号: RGPIN-2017-05391
• 负责人: Whalen, Joann
• 金额: $ 4.23万
• 依托单位: McGill University
• 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=634230
• 关键词: Biotic; controls; residence; time; soil

Increasing globalization of the agricultural sector and growth of the bioenergy sector creates incentives for Canadian farmers to produce more food, fiber and feedstock. This must be done sustainably, so agricultural products meet the high quality standards of processors and the general public, economic profits and jobs remain in our rural communities and farming activities are aligned with agro-environmental objectives. Sustainable agroecosystems are envisioned to conserve soil organic carbon (C) and rely more on internal soil nitrogen (N) recycling, thus contributing to C sequestration and avoiding inefficient N fertilizer use. Nutrient conservation is especially important in humid temperate regions of Canada because soils are more vulnerable to nutrient loss in areas with high precipitation regimes and 50% of Canadian farms are located in these regions. The ‘living soil’ concept is a possible solution since it relies upon the naturally-occurring soil microorganisms and fauna to simultaneous decompose and synthesize organic C and N, but since these processes occur rapidly, at a microscopic level, within soil pores, we do not know how the soil foodweb contributes to crop production at an farm operations level. Here, we will tackle the problem at three different scales: (i) from the pore-scale with stable isotope probing methods and high-resolution image analysis, (ii) considering energetics and trophic transfers that occur within the soil foodweb, and (iii) at the field scale, using an optimization modelling to determine the temporal transformations of organic and inorganic fertilizer inputs through the soil biotic community, in relation to crop nutrient demands. The novelty of this research program is its contribution to fundamental research questions regarding the biological processes that control C and N cycling in agroecosystems, which is integrated into an applied decision-making model that provides practical answers for the Canadian farming community. The principal investigator contributed to the training of many HQP in the past 6 years, including 10 M.Sc. and 16 Ph.D. graduates, More than 90 peer-reviewed papers were published in international journals during this period, most of which had HQP as first author. This proposal will support 12 trainees through an individualized training program that includes peer-to-peer mentoring and focuses on excellent scientific communication, networking and professional skills acquisition. This provides outstanding preparation for their future role as scientific leaders, as evidenced by the demand for these trainees in academic, government and industry jobs that require advanced technical skills and managerial abilities.

农业部门的日益全球化和生物能源部门的增长激励加拿大农民生产更多的粮食、纤维和原料。这必须以可持续的方式进行，以便农产品满足加工商和公众的高质量标准、经济效益和生产效率。我们的农村社区仍保留就业机会，农业活动与农业环境目标保持一致，可持续农业生态系统旨在保护土壤有机碳（C）并更多地依赖内部土壤氮（N）循环，从而有助于碳固存并避免。氮肥使用效率低下，养分保存在加拿大湿润温带地区尤其重要，因为降水量高的地区的土壤更容易遭受养分流失，并且 50% 的加拿大农场位于这些地区。这是一种可能的解决方案，因为它依赖于自然存在的土壤微生物和动物群同时分解和合成有机碳和氮，但由于这些过程在微观层面上在土壤孔隙内快速发生，我们不知道如何土壤食物网有助于农场运营层面的作物生产。在这里，我们将在三个不同的尺度上解决这个问题：（i）从孔隙尺度使用稳定同位素探测方法和高分辨率图像分析，（ii）考虑能量学和土壤食物网内发生的营养转移，以及（iii）在田间规模，使用优化模型来确定通过土壤生物群落的有机和无机肥料输入与作物养分需求的时间变化。该研究计划的新颖性在于其对有关控制农业生态系统中碳和氮循环的生物过程的基础研究问题的贡献，该研究被整合到一个应用决策模型中，为加拿大农业界提供了实用的答案。近6年来培养了多名HQP，其中包括10名硕士毕业生和16名博士毕业生，期间在国际期刊上发表了90多篇同行评审论文，其中大部分以HQP为第一。该提案将通过个性化培训计划为 12 名学员提供支持，其中包括同行指导，重点关注优秀的科学沟通、网络和专业技能的获取，这为他们未来担任科学领导者提供了出色的准备。学术、政府和行业工作对这些学员的需求需要先进的技术技能和管理能力。