Why use lawn fertilizer without phosphorus around lakes or streams?
It is estimated that just one pound of phosphorus in the water will produce 500 pounds of blue-green algae. Most soils in Eastern South Dakota naturally provide all the phosphorus your established lawn needs. Much of the phosphorus (phosphate) you apply actually runs off the lawn before penetrating the soil. That means it gets into the lakes and streams contributing to the blue-green algae bloom and growth of other undesirable aquatic plants. For this reason, Minnesota now has a statewide ban on the use of lawn fertilizer with phosphorus except on newly seeded lawns and where soil tests show it is needed. Why use lawn fertilizer without phosphorus in the City of Madison? A: Rain and lawn sprinklers can cause the excess phosphorus on city lawns to run off into the storm sewer system. From there it flows into Silver Creek and on into Lake Madison, Round Lake and Brant Lake. Studies estimate that about 10-13% of the phosphorus flowing into Lake Madison comes from runoff in the City of Mad
