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As increased levels of dissolved phosphorus are identified as a major concern dealing with the increased algal blooms found in Lake Erie, some folks have been pointing a finger at no-till as the cause. Yet the facts regarding phosphorus runoff in the Western Lake Erie Basin watershed near Toledo, Ohio, don’t back up that argument.
“Sure, there is a lot of no-till planting in the watershed,” says Steve Davis, the National Resources Conservation Service (NRSC) watershed specialist at Lima, Ohio. “But the percentage of long-term continuous no-till is still small in this area.”
This watershed includes 4.9 million acres in northwest Ohio, northeast Indiana and southeast Michigan. In any given year, about 40% of the watershed has no form of conservation tillage or protective residue cover on the soil surface at planting time.
Davis cites data from a recently completed 5-year study of the watershed to refute the claims against no-till.
While phosphorus can run off no-till fields, especially if it rains right after application, Davis says the same is true when phosphorus is applied to conventional- and minimum-tilled fields. He maintains several factors working together are more likely to explain the increase in levels of dissolved phosphorus runoff in Lake Erie: