Runoff generation and phosphorus mobilization in agricultural landscapes

以农业为主的流域非点源磷的输出是一个全球性问题，也是加拿大许多地区的优先领域，在加拿大的大型湖泊中，有害藻类水华（HABs）的发生频率越来越高。尽管实施了有益的管理措施（BMPs），以减少磷的损失，磷负荷并没有减少，事实上，在某些地区正在增加。现有的磷输出和管理策略模型主要针对降雨事件驱动的地表径流，无法有效解决冬季过程和融雪期问题。这一时期代表了一个显着的差距，在我们的科学认识磷动员在农业地区。在全球许多中纬度地区，冬季是径流和磷的主要年通量。因此，需要了解冬季和早春磷流失的驱动因素。 这个建议的目的，我的研究计划的短期目标是提高科学认识的冬季条件对磷供应和运输过程的影响，以及这些如何相互作用，以推动磷转移地表和地下径流。提高科学认识的径流产生和磷动员动态在农业集水区的表面和地下途径，需要制定和实施有效的战略，减少磷负荷，通过这两个途径。了解气候驱动因素在这些过程中的作用，也将有助于深入了解农业系统如何应对气候变化，如果条件从降雪为主转变为更多的降水为主，减少土壤霜冻已经预测。 实地调查将与滑铁卢大学在实地和实验室进行的新实验相结合，四名研究生将接受培训。我提出的研究将有重大的环境和经济影响，因为它解决了与气候（和气候变化）相关的问题和与农业管理（即人工排水）相关的问题。最重要的是，这项研究以冬季为目标，并以观测现场数据为基础，因此解决了一个重大的知识差距。

Phosphorus (P) export from non-point sources in agriculture-dominated catchments is a global issue, and a priority area for many regions in Canada, where Harmful Algal Blooms (HABs) have been observed in large lakes with increasing frequency. Despite the implementation of Beneficial Management Practices (BMPs) to reduce P loss, P loads are not decreasing and in fact are increasing in some regions. Existing models for P export and management strategies largely target rainfall event-driven surface runoff and do not effectively address winter processes and the snowmelt period. This period represents a significant gap in our scientific understanding of P mobilization in agricultural regions. In many midlatitude regions globally, the winter period is the dominant annual flux for both runoff and P. Thus, an understanding of the drivers of P loss in winter and early spring is needed. The objective of this proposal, and the short-term objective of my research program is to improve scientific understanding of the impacts of winter conditions on P supply and transport processes, and how these interact to drive P transfer in surface and subsurface runoff. An improved scientific understanding of runoff generation and P mobilization dynamics in both surface and subsurface pathways in agricultural catchments is needed to develop and implement effective strategies that reduce P loads via both of these pathways. An understanding of the role of climate drivers on these processes will also provide insight into how agricultural systems may respond to climate change, if conditions shift from snow-dominated to more precipitation dominated with reduced soil frost as has been projected. Field investigations will be coupled with novel experiments done in the field and in the laboratory at the University of Waterloo, and four graduate students will be trained as part of this work. My proposed research will have significant environmental and economic impacts as it addresses issues related to climate (and climate change) and issues that are relevant to agricultural management (i.e. artificial drainage). Most importantly, this research targets the winter period, and is based on observational field data, and therefore addresses a significant knowledge gap.