Reducing the impact of irrigated potato production on the risk of pesticide contamination of the Assiniboine delta aquifer
Karl Volkmar - Agriculture and Agri-Food Canada
To conduct studies to support the validation of a leaching model for pesticides used in potato production in the Assiniboine Delta Aquifer (ADA)
Manitoba is the second largest producer of processing potatoes in Canada, with the industry relying strongly on the ADA as a source of irrigation water. The ADA lies close to the surface and is very vulnerable to contamination through leaching of agri-chemicals, and the soils that overlie the ADA are considered particularly environmentally sensitive. This is problematic, considering that control of potato pests requires intensive pesticide application programs, sometimes as often as every 5 -10 days during the growing season.
In collaboration with the University of Manitoba and the Manitoba Department of Agriculture, and using new moisture meter technology, Agriculture and Agri-Food Canada researchers set out to evaluate the levels of risk to surface and ground water quality associated with different irrigation management practices.
Three potato production sites representative of specific agro-ecological sub-regions overlaying the ADA were selected as model sites. Irrigation management decisions were based either on the standard water balance methods in common use, or on % soil moisture content data as provided by moisture sensors. Groundwater, soil, and surface water samples were investigated for the presence of pesticides.
Overall, results indicated that irrigation practices can strongly influence the probability of pesticides leaching below the root zone, without affecting potato tuber yield. Although the project was discontinued for operational reasons, the findings indicate that follow-up studies would be warranted. It is likely that the choice of safer irrigation management practices will be shown to be an important approach in reducing the risk of groundwater contamination.
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