On 6/28/17, Michigan’s DEQ & MDARD employees expressed surprise about dissolved Phosphorus impacts & advocated for the need to “study” conservation practices for future years. More taxpayer funded “study halls” should be ended now. Current Ag practices are making the phosphorus problem in Lake Erie worse, or as the scientists stated: “unintended, cumulative, and converging impacts”. Source control must start with enforcement & reduction of manure waste, and treatment of manure.
This 2017 study shows what Heidelberg & others have known for a dozen years:
Increased soluble phosphorus loads to Lake Erie:
Unintended consequences of conservation practices?
Journal of Environmental Quality, Volume 46, Issue 1, 2017, Pages 123-132
Summary: Cumulative daily load time series show that the early 2000s marked a step-change increase in riverine soluble reactive phosphorus (SRP) loads entering the Western Lake Erie Basin from three major tributaries: the Maumee, Sandusky, and Raisin Rivers. These elevated SRP loads have been sustained over the last 12 years.
Within these watersheds, there have been long-term, largescale changes in land management: reduced tillage to minimize erosion and particulate P loss, and increased tile drainage to improve field operations and profitability. These practices can inadvertently increase labile P fractions at the soil surface and transmission of soluble P via subsurface drainage. Our findings suggest that changes in agricultural practices, including some conservation practices designed to reduce erosion and particulate Phosphorus transport, may have had unintended, cumulative, and converging impacts contributing to the increased SRP loads, reaching a critical threshold around 2002.