Managing Nutrient Pollution to Help Protect Water Quality
The Environmental Protection Agency (EPA) last week announced it has awarded nearly $9 million in grants to four institutionsi to fund research to help protect the quality of the nation’s waters by managing nutrient pollution. EPA Administrator Gina McCarthy characterized nutrient pollution as “one of America’s most widespread, costly and challenging environmental problems.” Inherent in this problem is a tension between food production and water quality.
What is Nutrient Pollution?
According to the National Oceanic and Atmospheric Administration (NOAA), nutrient pollution occurs “where too many nutrients, mainly nitrogen and phosphorus, are added to bodies of water and can act like fertilizer, causing excess growth of algae.” High levels of algae can degrade water quality by reducing or eliminating oxygen, which can harm aquatic life; it can also produce elevated toxins and bacterial growth, which can harm human health. Sources of nutrients in a given watershedii include wastewater, urban and suburban runoff during precipitation, and runoff from agricultural land.
Minimizing Agricultural Nutrient Pollution
Consumer Tips to Help Curb Nutrient Pollution
You don’t have to be a farmer to help curb nutrient pollution. Pet owners and homeowners can play a role too.
Homeowners can use lawn fertilizers responsibly by following applications directions carefully and not overusing fertilizer. University extension services offer free guidance on gardening responsibly. One example is the University of Maryland Extension Service’s Bay-Wise Program.
Dog owners can pick up pet waste using plastic bags sold for that purpose (recycled newspaper delivery bags may work well too) and dispose of bagged waste through municipally collected trash service.
According to the EPA website, “applying fertilizers in the proper amount, at the right time of year and with the right method can significantly reduce the potential for pollution.” The “agronomic rate” of nutrient application to crops is an important concept for farmers. It is the rate of application of nutrients through fertilizers that maximizes the benefit of adding nutrients without wasting product that will not be utilized by the crop.
In addition to adherence to agronomic rates, other strategies to help prevent nutrient pollution of waterways include: planting cover crops, such as certain grasses and grains to recycle excess nitrogen and reduce soil erosion; planting trees, shrubs and grass around fields to help absorb nutrients before they reach nearby water bodies; reducing how often fields are tilled to reduce erosion and soil compaction; keeping animals and their waste out of streams, rivers and lakes; and managing drainage water.
The US Department of Agriculture (USDA) website lists several innovative best practices for nutrient management. These include regular soil tests combined with the use of global positioning equipment to help characterize the spatial variation of nutrient needs within fields, enabling the efficient application of nutrients for crop growth. Similarly, manure tests help account for the nutrient content of manure applied as fertilizer. Additionally, the USDA website notes the precise timing of fertilizer application based on plant nutrient needs can help minimize waste. For example, most of the nitrogen needed by corn is required after the plant is three to four weeks old, so nitrogen application can be timed accordingly.
The Drinking Water Connection
A critical strategy for maintaining good quality drinking water is to protect the watershed. (See Protecting the Watershed: Step #1 for Clean Drinking Water.) Whereas nutrient application through fertilizers helps farmers do the important job of growing food for our hungry world, agricultural best practices significantly reduce the input of nutrients to receiving bodies of water, thereby protecting drinking water sources.
There is a great balancing act between the requirements for adequate food production and maintenance of good water quality. We look forward to the innovative solutions to nutrient pollution management that will result from the new EPA research grants. It should be money well-spent.
Chris Wiant, M.P.H., Ph.D., is president and CEO of the Caring for Colorado Foundation. He is also chair of the Water Quality & Health Council.
iPennsylvania State University Center for Integrated Multi-scale Nutrient Pollution Solutions; University of South Florida Center for Reinventing Aging Infrastructure for Nutrient Management; Colorado State University, Center for Comprehensive, Optimal, and Effective Abatement of Nutrients; and Water Environment Research Foundation, Alexandria, Va., National Center for Resource Recovery and Nutrient Management.
iiA watershed is a geographic region from which all precipitation drains into a given surface water system.