BE/CNH: Understanding Linkages Among Human and Biogeochemical Processes in Agricultural Landscapes

人类已经在多个尺度上深刻地改变了全球循环过程。目前的估计表明，在全球范围内，人类活动使生物活性氮的数量增加了一倍，其中农业占人类来源氮的75%。一系列复杂的环境和社会经济因素影响着农业肥料管理实践。社会经济子系统和生态子系统之间的联系被认为是追求可持续生态系统管理和提高氮利用效率的关键。必须解决人类和自然子系统之间的脱节，以及组件子系统内部的脱节。在人类领域内，污染者不支付与资源退化有关的费用。同样，由于高投入的工业化农业而进化的生物物理系统充满了生态脱节。例如，碳和氮循环的不耦合是农业系统的一个决定性特征，也是这些系统漏水的根本原因。平均而言，施用的氮肥中有45%到55%流失到环境中。本研究项目的目标是了解社会和生物物理子系统之间的相互作用如何影响多尺度集约管理的农业景观中的碳和氮循环。该项目的具体目标是：(1)研究人类子系统如何应对碳氮解耦的环境后果；(2)评估氮泄漏、机构能力和与退化水生资源的接近程度之间的关系；(3)确定哪些政策变化可能最有效地促进更有效的氮肥管理实践；(4)建模和模拟政策之间的多尺度相互作用。农场管理者和机构以及跨越时空的氮损失。为了了解制度是如何应对水生生态系统退化的，研究人员将比较切萨皮克湾和中西部地区所使用的制度和管理方法。在切萨皮克湾，过量氮输入的负面影响更多地由当地农民和农民自己经历，而中西部地区的负面影响要远得多。研究方法包括实地考察、同位素示踪剂研究、多尺度质量平衡的构建、与利益相关者的面对面访谈和调查、地理信息系统、遥感、全球定位系统、统计工具、系统建模和模拟。本项目对人-自然耦合系统理论和方法论、社会系统理论和环境政策具有启示意义。关于如何管理景观的人类和生物物理子系统的理论还没有得到很好的发展，特别是在集约管理、高投入的农业系统中。这项研究将加强对社会和生态系统涌现特性如何调解人类和自然系统之间相互作用的基本理解。除了使用综合跨学科方法外，研究人员还将从社会动态的微观经济模型出发，在微观经济模型中，个体行为者的总体行为被用来代表社会过程。他们将主要关注制度层面，在制度层面，社会涌现属性控制着社会和自然子系统之间的相互作用。该项目还将产生与制定农业和资源管理政策有关的实际成果。该项目得到了2005年度环境生物复杂性特别竞赛的支持，该竞赛侧重于自然和人类系统耦合动力学。

Humans have profoundly altered global cycling processes at multiple scales. Current estimates suggest human activities have doubled the amount of biologically active nitrogen on a global basis, with agriculture accounting for 75 percent of the human-derived nitrogen. A complex set of environmental and socio-economic factors influence agricultural fertilizer management practices. Linkages among socioeconomic and ecological subsystems are recognized as crucial in efforts to pursue sustainable ecosystem management and improve nitrogen-use efficiency. Disconnections between human and natural subsystems must be addressed as well as disconnections within the component subsystems. Within the human realm, those who pollute do not pay the costs associated with resource degradation. Likewise, the biophysical system that has evolved as a result of high, input industrial agriculture is fraught with ecological disconnections. For example, uncoupling of carbon and nitrogen cycles is a defining trait of agricultural systems and is the root cause of the leakiness of these systems. On average, 45 percent to 55 percent of fertilizer nitrogen applied is lost to the environment. The goal of this research project is to understand how interactions among social and biophysical subsystems impact on carbon and nitrogen cycles in intensively managed agricultural landscapes at multiple scales. Specific objectives of the project are (1) to investigate how the human subsystem responds to the environmental consequences of carbon nitrogen uncoupling, (2) to evaluate the relationships between nitrogen leakiness, institutional capacity, and proximity to degraded aquatic resources, (3) to determine which policy changes are likely to be most effective in promoting more efficient nitrogen fertilizer-management practices, and (4) to model and simulate multi-scale interactions among policies, farm managers, and institutions as well as nitrogen losses across space and time. To understand how institutions respond to degradation of aquatic ecosystems, the investigators will compare the institutions and management approaches used in the Chesapeake Bay, where the negative impacts of excess nitrogen inputs are experienced more locally and by the farmers themselves, to those in the Midwest, where the negative impacts are much more remote. Research methods include field research, isotopic tracer studies, construction of mass balances at multiple scales, face-to-face interviews and surveys with stakeholders, geographical information systems, remote sensing, global positioning systems, statistical tools, systems modeling, and simulation.This project has implications for coupled human-natural systems theory and methodology, social systems theory, and environmental policy. The theory of how the human and biophysical subsystems of managed landscapes is not well developed, particularly in the case of intensively managed, high-input agricultural systems. This research will enhance fundamental understanding of how social and ecosystem emergent properties mediate interactions among human and natural systems. In addition to using a synthetic interdisciplinary approach, the investigators will depart from a microeconomic model of social dynamics in which the aggregated behavior of individual actors is taken to represent social processes. They will focus primarily at the institutional level, where the social emergent properties govern the interactions between and social and natural subsystems. The project also will have practical outcomes of relevance to the development of agricultural and resource-management policy. This project is supported by an award resulting from the FY 2005 special competition in Biocomplexity in the Environment focusing on the Dynamics of Coupled Natural and Human Systems.