The title of the project is: "Ärvda föroreningslaster från jordbruk: Integrerad bedömning av biofysisk och socioekonomisk inverkan på vattenkvalitet i jordbruksekosystem".

Jerker Jarsö is project Manager and Gia Destouni is also in this project and partner universities are: University of Waterloo, Kanada (Project Coordinator), University of Coimbra, Portugal, University of Copenhagen, Danmark.

The last 100 years have seen a more than threefold increase in world population accompanied by massive changes in land use and agricultural intensification to secure an adequate food supply. Human activities have greatly accelerated the nitrogen (N) and phosphorus (P) cycles, with excess N and P leaching into surface and groundwaters, causing problems of eutrophication, aquatic toxicity and drinking water contamination. Protecting water quality in the face of a growing population and the corresponding demands on agriculture is critical to ensuring both water and food security for generations to come.

In Europe, adoption of the Water Framework Directive (WFD) in 2000 has resulted in numerous national policies designed to achieve the WFD’s objectives of good chemical and ecological status. In Canada, agricultural non-point source pollutants (NPS, primarily N and P) have been implicated in the resurgence of algal blooms in the Laurentian Great Lakes.2 The 2012 Great Lakes Water Quality Agreement explicitly commits Canada and the US “to support the ongoing development and implementation of new approaches and technologies for the reduction of phosphorus (P) from agricultural and rural non-farm sources.”

However, despite implementation of a range of agricultural best management practices (BMPs), efforts to reduce excess nutrients entering water bodies have often been disappointing, and water quality targets have not been met. For example, in 1988 Sweden decided to reduce nutrient loads to 50% of 1984 levels by 1995; in practice, however, only a 15% reduction was achieved. In Canada’s Grands River watershed, time lags between decreases in N surplus and changes in flow-averaged nitrate concentrations are on the order of 25 years. Such time lags can in many cases be attributed to the presence of legacy nutrient stores that have accumulated in the landscape.

The project “Legacies of Agricultural Pollutants (LEAP): Integrated Assessment of Biophysical and Socioeconomic Controls on Water Quality in Agroecosystems” aims to develop a unified framework that explicitly incorporates agricultural nutrient legacies and time lags into adaptive management strategies to protect water resources under changing climate and land use. The research will integrate the following three components.

(1) Biophysical: LEAP will fill key knowledge gaps and develop watershed-scale nutrient modelling tools necessary to determining impacts of historical land-use patterns on current nutrient loading to surface and groundwater. (2) Economic: LEAP will account for trade-offs between initial costs of BMP implementation and delayed benefits of water quality improvements by evaluating appropriate discounting methods. (3) Policy: by quantifying nutrient legacies and associated lag times, LEAP will help select appropriate BMPs and establish nutrient reduction goals within realistic time frames.

The comparative studies will allow LEAP to identify how differences in climate and landscape settings, as well as agricultural histories and socioeconomic conditions lead to differences in the relative successes of interventions to improve water quality. We envision that such improved understanding will enable us to create a roadmap for including agricultural pollutant legacies in environmental policy and decision-making.