Here's an interesting piece about lakes & phosphorus. Former MLCI board member Laura Wilson - an expert on the topic - is quoted in the story.
(AUGUSTA)- Maine's new law is both effective and efficient at protecting clean water. The law passed last year, prompted by the problems phosphorus causes in lakes and streams, requires all retailers who sell lawn fertilizers to post a sign discouraging the use of phosphorus lawn products unless reseeding or starting a new lawn. The law has reduced the amount of phosphorus fertilizers used in Maine and the amount that washes off into Maine waters.
These conclusions are based on data from compliance checks by the Department of Environmental Protection staff during the summer of 2008. Eighty-seven percent of surveyed stores had signs posted. In addition, most retailers (97%) carried at least one type of phosphorus free (P-free) fertilizer and many of the large retailers were carrying all P-free products with the exception of Starter fertilizer (which contains some phosphorus to help start new lawns).
Maine soils generally have plenty of phosphorus so it is a waste of time and money to apply more unless a soil test says it is needed. The extra phosphorus runs off with the next rain to fertilize our waters creating nuisance algal blooms. "Most lawns don't need phosphorus, according to University of Maine Cooperative Extension's Laura Wilson. "About 90% of the lawns that were tested for phosphorus had plenty in their soil," notes Wilson.
Research shows that a healthy lawn can be achieved with fewer lawn chemicals. If a lawn is 10 or more years old, grass clippings, a natural fertilizer for the budget minded, provide enough nutrients in the soil to grow a healthy lawn, so additional fertilizer is not needed. Younger lawns may need some nitrogen, but phosphorus is not needed. "If a lawn doesn't need fertilizer and phosphorus in particular, don't apply any," says Wilson. "Homeowners waste time and money applying fertilizers -- and may harm local waters."
If homeowners need to add fertilizer, the new law has not increased consumer cost. In a comparison of similar lawn fertilizer products in two neighboring states, the cost of P-free lawn fertilizer was found to be the same as lawn fertilizer which contains maintenance levels of phosphorus.
For more information, visit MaineDEP.com on the web.