Urban Fertilizers & the Chesapeake Bay:

An Opportunity for Major Pollution Reduction
Released by: Environment Maryland Research and Policy Center

Executive Summary

For more than 26 years, states in the Chesapeake Bay region have attempted to clean up the Bay, but it continues to choke on a lethal overdose of pollution. In order to achieve a clean, sustainable Bay, states in the Bay watershed will have to reduce nitrogen levels in Bay waters another 30 percent and reduce phosphorus by an additional 8 percent—in spite of a projected population increase of 30 percent by the year 2030. Reductions of that magnitude will only be possible if governments target all the watershed’s sources of nutrient pollution.

Excess nitrogen and phosphorus, along with sediment, is a leading cause of recurring poor water quality in the Bay and the waters that feed it. About 30 percent of the Bay’s phosphorus load comes from urban and suburban runoff. Those same developed lands account for 10 percent of the nitrogen-tainted runoff. Yet not nearly enough has been done to reduce nutrient runoff from developed lands.

While Maryland regulators are requiring farmers to do better at controlling nutrient-laden runoff from their fields, the state is mostly ignoring the watershed’s dominant crop: grass. Throughout the Bay watershed, nearly 3.8 million acres are now planted in turf grass, and the acreage is growing as residential development expands and replaces farm fields.

Turf grass is Maryland’s biggest crop by far, with as much as 1.3 million acres planted in grass statewide. That compares with 1.5 million acres planted for all other crops in Maryland in 2009. Yet it is the least regulated of the state’s major crops. Turf grass becomes a pollution problem when it is covered with too much fertilizer, which contains nitrogen and phosphorus. The nutrients in fertilizer can help maintain healthy lawns, but in excess they can wash into nearby waters when it rains or snows. Excess fertilizer nutrients can also seep directly into groundwater. Whether the fertilizer is organic or chemical, its nutrients can harm the Bay and local waterways.

Tracking fertilizer use on developed land is such a low priority that the state doesn’t keep statistics on it, but Maryland Department of Agriculture records show “nonfarm use” fertilizer sales are quickly catching up to farm fertilizer sales. The best estimates suggest that Maryland landowners apply at least 86 million pounds of nitrogen fertilizer to state lawns every year.

This fertilizer makes its way into rivers and the Bay. In one suburban Baltimore watershed, researchers found 56 percent of the nutrients in a local stream came from lawn fertilizer. Scientists in Texas, Wisconsin, Minnesota, Connecticut and Canada have also confirmed that pollutants in lawn fertilizer can significantly harm surface water quality.

Other states have taken action to address this important, fast-growing pollution source. Minnesota was the first state to ban phosphorus in lawn fertilizer beginning in 2002. A follow-up survey found this is one method of reducing nutrient pollution that was popular with consumers and cost nothing.

Because phosphorus can build up to high levels in soils, Minnesota officials think there will be a lag until about 2012 before they see improved water quality as a result of the ban. But in Ann Arbor, Michigan, a similar ban produced quicker results. Within a year of enacting the citywide ban, phosphorus levels in the nearby Huron River dropped an average of 28 percent.

Other states, including New York and New Jersey, have recently banned phosphorus in lawn fertilizer, imposed buffer zones around water bodies, and taken other steps to limit fertilizer runoff from lawns.

Maryland’s law on fertilizer usage is weak. It requires the 700 lawn care companies and other businesses that fertilize 10 acres or more of “non-farm land” to follow University of Maryland Cooperative Extension Service guidelines on fertilizer use and to submit annual reports to the Maryland Department of Agriculture. The state reviews less than 10 percent of these reports each year. State reviewers routinely find that roughly one-fourth of the companies fail to take basic steps to minimize fertilizer use, such as testing the soil to find out whether additional fertilizer is needed. The maximum fine for violating the state lawn fertilizer regulations is $1,000. But in 2009 the state collected only one $250 fine. Despite the state Agriculture Secretary’s pledge to make enforcement of nutrient management regulations a high priority, in 2010 the state again collected only one fine.

Though they are not impacted directly by existing laws, homeowners can play a critical role in reducing urban fertilizer pollution. Maryland does very little to teach consumers about the environmental harm done by over-fertilizing lawns, or to demonstrate Bay-safe fertilizing strategies. The state Extension Service literature on the subject is confusing and contradictory, and its only outreach effort is through the state’s volunteer Master Gardeners.

Reducing urban fertilizer pollution means both limiting the nutrients in the fertilizer itself and ensuring applicators put less fertilizer on the ground. The following low-cost policies would help achieve both goals:

  • Rewrite the existing guidelines that dictate how and when professionals apply fertilizer such that the guidelines are aligned with statewide water quality restoration goals for the Chesapeake Bay and its tributaries
  • Ban phosphorus from all fertilizers, organic and synthetic, intended for use on established turf grass 
  • Require a science-based upper limit on the amount of nitrogen in all fertilizers intended for use on established lawns, and require that at least a fifth of the nitrogen be “slow-release,” which leads to less runoff
  • Provide adequate funding so the state can enforce fertilizer usage by professional applicators as well as fertilizer manufactures and distributors
  • Prohibit application of fertilizer in specific situations that would facilitate runoff, such as applying when the ground is frozen or when rainfall is expected