Toward a mechanistic understanding of coupled biogeochemical cycles in human-dominated landscapes

对人类主导景观中耦合生物地球化学循环的机械理解

• 批准号: RGPIN-2016-04920
• 负责人: MacDonald, Graham
• 金额: $ 2.11万
• 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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615381
• 关键词: Toward; mechanistic; understanding; coupled; biogeochemical

Human activity is profoundly altering biogeochemical cycles, with important implications for the provision of ecosystem services that are vital to society. Sustainable nutrient management strategies in agriculture are a critical lever to reduce these impacts while supporting long-term food security and water quality. Yet, we have relatively limited understanding of how agricultural activities and urbanization affect the interaction among biogeochemical cycles (such as nitrogen, phosphorus, and carbon) that can in turn influence ecosystem services. Another management challenge is that we lack mechanistic models of how these human impacts on nutrient cycling moderate the provision of specific services. Closing these knowledge gaps related to human-dominated systems is critical as global food demand increases and urbanization continues. My research program will address these challenges while training students in statistical and spatial analysis, nutrient budget accounting, and ecosystem service modeling. A first objective for my students and I is to quantify the ratio of soil nitrogen, phosphorus, and organic carbon in diverse agroecosystems through synthesis of data from published studies worldwide. We will use these data to test to what degree climate, soil type, and farm management mediate soil nutrient ratios. Second, we will explore how specific nutrient management strategies affect soil nutrient balances and the provision of multiple ecosystem services using hypothesis-driven mechanistic models. Our primary focus will be on the relationship between agricultural nutrient use and water quality, including how shifts in the ratio of nitrogen versus phosphorus use affects water quality in downstream lakes and rivers across North America. A third objective focussed on urban areas is to quantify the magnitude and variation of nutrient and carbon flows from agricultural lands to cities. Our models will enable estimation of how much fertilizer use is embodied in urban diets and how this affects the capacity of local croplands to recycle nutrients from urban waste streams based on their nutrient ratios. These interrelated objectives will provide new understanding of how tightly flows of nutrients and carbon are linked within and across human-dominated landscapes, as well as how agricultural nutrient management could be a mechanism that drives changes in the provision of multiple ecosystem services over space and time. The overall goal of my research program is to help inform how we can balance competing aims to enhance agricultural productivity and environmental quality in an era of agricultural intensification and urbanization. Findings from my proposed studies will contribute to advancing interdisciplinary research on agricultural and urban dimensions of coupled biogeochemical cycles, with potential application for land managers and city governments in Canada and abroad.

人类活动正在深刻改变生物地球化学周期，对提供对社会至关重要的生态系统服务具有重要意义。农业中的可持续营养管理策略是减少这些影响的同时支持长期粮食安全和水质的关键杠杆。然而，我们对农业活动和城市化如何影响生物地球化学周期之间的相互作用（例如氮，磷和碳）的相互作用相对有限，从而影响生态系统服务。另一个管理挑战是，我们缺乏这些人类对养分循环的影响如何适应特定服务的机械模型。随着全球粮食需求的增加和城市化的延续，缩小与人类主导系统有关的这些知识差距至关重要。我的研究计划将在培训学生进行统计和空间分析，营养预算会计以及生态系统服务建模时应对这些挑战。 我和我的学生的第一个目标是通过综合全球已发表研究的数据来量化各种农业生态系统中土壤氮，磷和有机碳的比率。我们将使用这些数据来测试气候，土壤类型和农场管理的程度介导的土壤养分比。其次，我们将探讨使用假设驱动的机械模型如何影响土壤养分平衡以及提供多个生态系统服务的特定营养管理策略。我们的主要重点将是农业营养用途和水质之间的关系，包括氮与磷的比率的变化如何影响北美下游湖泊和河流的水质。关注城市地区的第三个目标是量化从农田到城市的养分和碳流量的幅度和变化。我们的模型将估计城市饮食中体现了多少肥料的使用，以及这如何影响当地农田根据其营养比率回收城市废物流中营养物质的能力。 这些相互关联的目标将为营养和碳的紧密流动如何在人类主导的景观内部和范围内与农业营养管理如何相连，从而使提供多个生态系统服务在超时和时间上提供多个生态系统服务的变化。我的研究计划的总体目标是帮助我们如何平衡竞争旨在在农业强化和城市化时代提高农业生产力和环境质量。我拟议的研究的发现将有助于推进耦合生物地球化学周期的农业和城市层面的跨学科研究，并在加拿大和国外的土地经理和城市政府中使用了潜在的应用。