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Video: How does tile drainage affect water quality in Wisconsin?
March 31, 2025 By Drainage Contractor
In a recent presentation, University of Wisconsin agriculture water quality specialist Laura Paletta and conservation profession training program director Kevin Erb spoke to the impacts of tile drainage on water quality and finding old tile lines when maps and records are lost in this video from University of Wisconsin.
On a per-county basis, Wisconsin doesn’t boast as much drainage as other nearby Midwest states such as Iowa and Minnesota –there is a bit more in the northeast, which Paletta says is probably due to the higher prevalence of clay soils. “Even though the state doesn’t have as much tile drainage, it still does exist here,” says Paletta, and it’s a “hot topic” of interest in the state, which thus raises questions about water quality.
Studies and data from Discovery Farms Wisconsin looked at specific nutrient and water quality effects when tile is present. Paletta compared Discovery Farms’ study to one from Northern New York, which collected edge-of-field runoff in tiled systems. Both studies found tile did not play a role in total phosphorus, however total N and nitrate did increase in tiled systems. Paletta acknowledged that part of the strategy is to think about management “before it gets into the water,” as well as once it gets into the tile.
“Improving our nitrogen management is a great way to try to limit that nitrogen movement before it gets into our tile,” said Palette. She looked at split nutrient applications, or more thoughtful timing, a 4R nutrients stewardship approach, cover crops and more. Solutions within tiled systems ranged from simple to complex, including controlled drainage, open ditches, saturated buffers, drainage water recycling and more. “All of [the strategies] work similarly – they try to use denitrification to reduce the nitrates,” she said.
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