Phase out phosphorus in lawn fertilizer (SB 197)

• About this bill
• Statewide ban on phosphorus lawn fertilizer would benefit lakes
• What is phosphorus?
• How can too much phosphorus negatively affect lakes?
• How much phosphorus do healthy lawns need?
• How do I know if my lawn needs phosphorus fertilizer?
• How can I tell if a fertilizer is phosphorus free?
• What if I don’t live near a lake, stream, or wetland?

The Wisconsin Association of Lakes has been working with the legislature on a bill to prohibit the use, sale, and display of phosphorus lawn fertilizer (with certain reasonable exceptions). We are pleased that the Senate has passed this initiative (SB 197) with strong bi-partisan support.

Quick points

• The vast majority of Wisconsin’s lawns are saturated with too much phosphorus, a nutrient commonly found in fertilizer.
• Phosphorus runoff from lawns goes directly into surface waters, fueling smelly algae blooms and nuisance plant growth, suffocating fish, and making summertime unpleasant for property owners and recreational users on some of Wisconsin’s beautiful lakes.
• This bill enjoys broad support across the state from county and local governments, local lake groups, statewide conservation organizations, and others interested in cleaner, safer, healthier lakes for everyone.
• Using phosphorus free lawn fertilizer is one easy step everyone can take to improve water quality.
• This bill would make the right fertilizer choice for lakes—phosphorus free lawn fertilizer—the default choice for consumers.

About this bill

• Bill generally prohibits application of lawn fertilizer that contains phosphorus to lawns, golf courses, and other mowed grassy areas (turf)
  • Prohibition does not apply to land used for agricultural production
  • Consumers can use phosphorus lawn fertilizer if a soil test demonstrates phosphorus is needed, or during the first growing season when a new lawn is being established.
    
• Bill prohibits the retail sale of phosphorus lawn fertilizer unless is being sold for one of the permitted uses
  
• The bill ensures the default fertilizer choice for consumers is phosphorus free by prohibiting retailer from displaying phosphorus lawn fertilizer.
  • Retailers can post signs to let consumers know phosphorus fertilizer is available and consumers can request phosphorus for permitted uses.
  • Bill builds in time for retailers to sell their existing inventory of phosphorus fertilizer.
    
• Bill prohibits application of fertilizer on frozen ground and impervious surfaces
  

Statewide ban on phosphorus lawn fertilizer would benefit lakes

Polluted runoff is Wisconsin's number one water quality problem, degrading or threatening an estimated 90% of inland lakes. Phosphorus is the main nutrient that drives eutrophication in most lakes. Using phosphorus-free lawn fertilizer is one easy way everyone can contribute to better water quality—regardless of where they live.

Adding phosphorus lawn fertilizer to soil that already has sufficient phosphorus to maintain a healthy lawn contributes to chronic nutrient loading problems. Excess phosphorus is stored in watershed soils, where it slowly works its way towards surface waters. Although not all phosphorus stored in watershed soils will reach lakes, only a small amount is needed to maintain or "tip" a lake into a nutrient rich (eutrophic) state. This sensitivity of lakes and rivers to phosphorus means even small sources of phosphorus in runoff—that by themselves may seem inconsequential—can result in water quality problems as phosphorus from lawns, streets, farm fields, and other sources in the watershed wash into lakes.

Changing land use patterns throughout a watershed can also increase the volume and rate of flow of runoff into lakes. In an undisturbed watershed, vegetation slows down runoff and water soaks into the soil. Development pressure frequently replaces lands that were once wooded or open space with lawns and hard surfaces (such as roads, buildings, and compacted soils). Water cannot penetrate these hard surfaces and runs off rather than soaking into the ground. Studies have indicated that lawns also significantly reduce infiltration of water, and increase both the amount of runoff and nutrients making its way to the lake.

Converting a natural shoreline into a lawn and unnecessarily applying phosphorus fertilizer are some of the many watershed changes that exacerbate the impacts polluted runoff has on lakes.

Statewide policy needed

Using phosphorus free lawn fertilizer—unless a soil test confirms the nutrient is needed—is a common sense, simple, and cost effective way to reduce the amount of nutrients entering our waterways. Many lake groups, local governments, counties and citizens are calling for a statewide phosphorus lawn fertilizer ban modeled after Dane County's existing ordinance. A statewide policy would save local governments the duplicative costs of developing independent ordinances and ensure consistency for consumers, retailers, and suppliers.

Dane County was uniquely able to pass a county-wide phosphorus fertilizer ordinance because the legislature gave the Dane County Lakes and Watershed Commission the authority to regulate fertilizers. No other Wisconsin county has this authority to create a county-wide ordinance to regulate fertilizer. Several counties have passed resolutions supporting a statewide ban on the sale and use of phosphorus lawn fertilizer, modeled after Dane County's existing ordinance.

Dane County model a fit for Wisconsin

Dane County passed its county-wide phosphorus lawn fertilizer ordinance in 2004. Like Minnesota's statewide law, the ordinance allows people to use phosphorus lawn fertilizer if a soil test demonstrates the nutrient is needed. A simple, inexpensive soil test tells property owners if their lawn already has enough phosphorus. Phosphorus free fertilizers are available at a comparable cost to phosphorus fertilizers.

The ordinance also allows phosphorus fertilizer to be used on newly established turf and lawns during their first growing season and exempts fertilizer intended for flower and vegetable gardening, indoor plants, and agricultural trees and shrubs. Yard waste, compost, and biosolids intended primarily as soil amendments are also exempt from the ordinance.

Dane County's ordinance ensures the default fertilizer choice for consumers is phosphorus free by prohibiting retail display of phosphorus fertilizer. This provision ensures the system is self regulating. Retailers do not have to monitor their customer's purchases as customers have to specifically ask for phosphorus fertilizer products. Because of Minnesota's statewide law, regional supplies of phosphorus free lawn fertilizer are readily available.

Activity in other states

In 2002 Minnesota became the first state in the nation to regulate phosphorus fertilizer use on lawns and turf. Other states are considering similar legislation to better protect the water quality of their lakes.

Maine has introduced a bill that would prohibit the sale or use of fertilizer containing phosphorus for nonagricultural lawn or turf unless a soil test indicates that additional phosphate is needed or the fertilizer will be used in the establishment of a new lawn.

Several local units of government in Michigan have passed ordinances to restrict or ban use of fertilizers containing phosphorus. Muskegon County in southwest Michigan recently passed the state's first countywide ban.

The City of Ann Arbor's ordinance, developed with the Huron River Watershed Council, went into effect on January 1, 2007. Runoff from the use of fertilizers is a significant source of phosphorus to the Huron River, and researched showed that the City of Ann Arbor was contributing 67% of the total phosphorus load to the river. According to the Malletts Creek Restoration Study, estimates of full compliance in a phosphorus free fertilizer program would result in a 22% reduction in phosphorus loading to the Huron River, helping the city comply with a federal mandate to reduce phosphorus loading to the Huron River.

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What is phosphorus?

Phosphorus is an essential nutrient plants need to grow, and is a common ingredient in many fertilizers. Plants don't absorb more phosphorus than they can use. Extra phosphorus from lawns can wash into our lakes and streams, causing algae blooms, water quality decline, as well as negatively impact recreational use and lakeshore property values.

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How can too much phosphorus negatively affect lakes?

Phosphorus provides the fuel algae need to transform lakes into a thick, smelly green soup. Where it takes 20 parts per million of soil phosphorus to grow healthy turf, 25 parts per billion (a quantity 1,000 times smaller) can promote excessive algae growth in lakes. One pound of phosphorus can support 500 pounds of algae.

Algae clouds water and blocks sunlight from reaching aquatic plants potentially changing the lake's ecosystem; it also lowers the oxygen levels in the water, which can cause fish kills. Nutrient rich waters are preferred by invasive species such as Eurasian water milfoil, curly leaf pondweed, and carp.

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How much phosphorus do healthy lawns need?

Although the amount of phosphorus in Wisconsin soils can vary, many residential lawns already have more than enough phosphorus to support a healthy lawn. Because plants do not absorb more fertilizer than they can use, your lawn does not benefit from phosphorus fertilizer if there is already a sufficient amount of phosphorus in the soil. Healthy lawns can be maintained with phosphorus free fertilizers.

A healthy lawn needs 20 parts per million (ppm) of phosphorus. The UW Soils lab data finds agricultural soils in every Wisconsin county are above 20 (average 53 ppm); some counties have significantly higher phosphorus levels in their soil. Recent data estimates phosphorus levels on residential Wisconsin lawns have, on average, twice the amount of phosphorus (105 ppm) than the average farm field; five times more than necessary for healthy lawns.

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How do I know if my lawn needs phosphorus fertilizer?

A simple, inexpensive soil test tells property owners if their lawn already has enough phosphorus.The University of Wisconsin recommends testing your lawn and garden soil every three years to learn how much fertilizer you need to apply.

The UW Soil & Plant Analysis Lab can measure the level of phosphorus in your lawn's soil. Use a small garden trowel to collect soil from at least 5 locations around your lawn. For established lawns, dig down around 4 inches to collect your sample (for gardens and new lawns, dig down 6 inches). Combine samples in a clean plastic bag. You need around 1-2 cups for the test.

Phosphorus free fertilizers are available at a comparable cost to phosphorus fertilizers.

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How can I tell if a fertilizer is phosphorus free?

The amount of Nitrogen, Phosphorus, and Potash in a bag of fertilizer is shown by a series of three numbers on the package. The middle number indicates the amount of phosphorus the fertilizer contains. Look for the middle number of "0" to be sure you are buying phosphorus free fertilizer.

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What if I don’t live near a lake, stream, or wetland?

No matter where you live, using phosphorus-free lawn fertilizer is one easy way everyone can contribute to better water quality. Even if you do not live close to water, runoff from your lawn flows into the storm sewer system which directly empties into many lakes, streams, and wetlands.

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