At a recent Michigan conference, it was disclosed that of approximately 2,000 soil samples submitted by lawn owners in a particular watershed, 99% had sufficient phosphorus, without fertilizer, to support healthy growth.
Phosphorus is a key factor in algae blooms that have worsened in recent years in some areas of the Great Lakes. At least two southern Michigan rivers exceed the state's phosphorus standard and are looking for cost-effective ways to reduce phosphorus pollution.
Minnesota has already found it:
http://www.moea.state.mn.us/campaign/download/phosphorus.pdf
Posted by Dave at October 20, 2005 08:42 PM