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Posted 5 June 2009. Applied Turfgrass Science. Careful Fertilizer Use Helps Protect Water Quality Michigan State University. www.canr.msu.edu East Lansing, Michigan (May 27, 2009)-- Everyone who uses fertilizer in a garden, lawn or landscape has a part to play in keeping plant nutrients out of surface water and groundwater.
“Nitrogen and phosphorus are two of the three major nutrients in commercial fertilizers,” says Darryl Warncke, crop and soil scientist at Michigan State University. “In the right place and at the right time -- in the soil where plant roots can take them up and when plants are growing -- they benefit us by helping us grow healthy, productive plants.” They can also promote unwanted plant growth in surface water and contaminate groundwater, the major source of drinking water in Michigan. The first step in keeping them out of the water supply is to apply only the nutrients that plants need at the best time for plants to use them. The best way to avoid applying excessive nutrients that could run off to surface water or move down through the soil to groundwater is to have a soil test done and follow the recommendations, Warncke says. Soil test recommendations take into consideration factors such as soil type and intended crop. Other factors are soil moisture, rain and irrigation, and ground cover. “For example, if you apply the same amount of fertilizer on a clay loam soil and a sandy soil, water moving quickly through the sandy soil can carry nutrients out of the plant root zone before plants can take them up,” he explains. “Likewise, if a clay soil is saturated, surface-applied fertilizer will run off rather than soak in with rain or irrigation. And runoff is more likely on bare soil than on soil covered with turf, crop debris or mulch.” Fertilizer that falls on paved surfaces should be swept up or swept into lawn or garden areas so that it doesn’t run off into ditches or storm drains leading directly to surface water, he advises. Gardeners with sandy soil can reduce the chances of nutrients leaching to groundwater by dividing recommended amounts into two or more applications to be made when plants are actively growing. Avoid fertilizing when heavy rains are expected, and avoid overirrigating, he adds. “One homeowner’s careless use of fertilizer may seem insignificant, but a lot of home gardeners being careful with fertilizer and other potential contaminants can make an impact on the quality of surface water and groundwater,” he says. “All it takes is thinking about the fertilizer you’re applying and where it may end up, and then doing everything you can to assure that the plant nutrients you’re applying benefit the plants in your yard rather than ending up in the nearest creek.” Contact: Leslie Johnson |
