Runoff generation and phosphorus mobilization in agricultural landscapes

在以农业为主的流域中，非点源磷(P)的出口是一个全球性问题，也是加拿大许多地区的优先领域，在这些地区，在大型湖泊中观察到有害藻华(HAB)的频率越来越高。尽管实施了有益管理做法(BMP)来减少磷损失，但磷负荷并没有减少，实际上在一些地区还在增加。现有的磷输出和管理战略模型主要针对降雨事件驱动的地表径流，没有有效地处理冬季过程和融雪期。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，有必要了解冬季和早春磷流失的驱动因素。 这项建议的目的和我的研究计划的短期目标是提高对冬季条件对磷供应和运输过程的影响的科学理解，以及这些影响如何相互作用来驱动地表和地下径流中的磷转移。为了制定和实施通过这两种途径减少磷负荷的有效策略，需要对农业集水区地表和地下途径中的径流产生和磷动员动态有更好的科学理解。了解气候驱动因素在这些过程中的作用也将有助于洞察农业系统可能如何应对气候变化，如果情况如预测的那样从以雪为主转向以降雨量为主、土壤霜冻减少的情况。 滑铁卢大学将在实地考察和实验室中进行新颖的实验，四名研究生将作为这项工作的一部分接受培训。我拟议的研究将产生重大的环境和经济影响，因为它涉及与气候(和气候变化)有关的问题以及与农业管理有关的问题(即人工排水)。最重要的是，这项研究以冬季为目标，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.