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Dane County Land & Water Resources Department

Phosphorus

Phosphorus is a key nutrient needed for plant growth which is why it is often applied to gardens, lawns and agricultural fields. However, when it rains phosphorus can run off into local water bodies and fuel algae growth instead. One pound of phosphorus can produce up to 500 pounds of algae. Dane County and community partners are involved in many initiatives in both rural and urban areas to reduce phosphorus runoff, and several are described below.

 

What Dane County Is Doing

 

Yahara Watershed Phosphorus Reduction Initiatives

To address the issue of phosphorus in the Yahara Watershed, 30 partners have come together to pioneer a new regulatory approach called watershed adaptive management in which all sources of phosphorus in a watershed work together to meet water quality goals related to phosphorus. Find out more about the Yahara Watershed Improvement Network (WINs) project on the Madison Metropolitan Sewerage District website.

Prior work and phosphorus reduction investments in the Yahara watershed set the stage for current collaborative phosphorus reduction successes. This work included the Yahara CLEAN initiative that began in 2008.

 

Lawn Fertilizer

In order to improve lake water quality by reducing phosphorus runoff, based on the recommendation of the Dane County Lakes and Watershed Commission, the Dane County Board adopted Ch. 80 of the Dane County Code of Ordinances, "Establishing Regulations for Lawn Fertilizer Application and Sale." Fertilizers normally contain a mix of nutrients, including nitrogen, phosphorus and potassium.  The ordinance went into effect in January 2005 in every town, village and city in Dane County. Signs containing the ordinance requirements and the effects of phosphorus on Dane County waters must be prominently displayed where lawn fertilizers are sold.

The ordinance:

  • Prohibits use of phosphorus-containing lawn fertilizers, unless a soil test shows that phosphorus is necessary, or the fertilizer is to be used on a new lawn in its first growing season.
  • Prohibits retail display of phosphorus-containing lawn fertilizers

Signs for Retailers:

 

Manure Management

In 2008, a Community Manure Feasibility Study Committee completed its examination of alternatives for livestock manure management in Dane County that would allow the livestock industry to continue to survive, protect water quality, and protect open space. The work of this committee paved the way for development of new community manure management initiatives. 

Dane County has also established requirements for manure storage, and for winter application of stored pumpable liquid manure in order to protect the health and welfare of Dane County’s residents and the economic and environmental value of the county’s natural resources. Staff administer these programs and assist agricultural producers with nutrient management planning and other conservation practices.

 

Leaf Management

Decaying leaves are a great natural fertilizer for gardens and lawns, but they also release unwanted nutrients into our local waters. When it rains, stormwater flows through leaf piles in streets creating a "leaf tea" that is rich in dissolved phosphorus. The phosphorus present in this "leaf tea" is not removed through traditional stormwater treatment practices and is carried through our storm sewers to local lakes, rivers and streams. Learn how you can help keep streets leaf-free and protect local water resources on the Ripple Effects website.

 

What Dane County Residents Can Do

In urban and rural areas:

  • Test your soil before fertilizing to find out what nutrients it needs. Learn more about lawn care and soil tests (PDF) from the UW Extension.
  • Remove leaves from your street before it rains. Find out more on the Ripple Effects website.
  • Reduce the amount of rainwater running off your property by installing a rain barrel or rain garden.

In rural areas: