Decreasing contamination of runoff: The positive impacts of turfgrass

A stand of turfgrass maintained through application of fertilizer (a) will generally be healthier than one where fertilizer is restricted (b). Runoff carrying sediment and dissolved pollutants is more effectively absorbed and is given more time to infiltrate when the turf is healthier, though storms large enough to cause runoff may carry away excess fertilizer. In contrast, an unfertilized stand of turf will allow for higher volumes of runoff less likely to carry nutrients such as phosphorous and nitrogen. Image courtesy Chris Murray

By Christopher Murray, PhD

What role might turfgrass play in protecting water quality? Those who have ever noticed hydroseeding operations at a new development may already know turfgrass is a recognized means of stabilizing soil and preventing it from being carried away in runoff—a strategy for improving quality. Once the turfgrass is established, it continues to assist in management of both runoff quality and—increasingly, as the turf grows—quantity. As shoot density rises and the plant growth contributes to the soil’s permeability, the turf softens the impact of rainfall and restores some of the absorptive capability of the landscape. As the turfgrass grows, its ability to hold water and reduce the volume of runoff rises.

With this positive impact in mind, it is clear turfgrass maintenance is more than a purely cosmetic practice and it is worth looking closely at the risks and benefits associated with the use of fertilizer. Where there is less runoff, there may be less pollution; although it is counterintuitive, a stand of turfgrass made healthier through fertilization may allow less runoff to escape, reducing the nutrients carried into rivers and lakes. On the other hand, adding fertilizer must increase the amount of nutrients available to be carried away by runoff, so one would expect the concentration of pollution to grow, even though the volume might decrease.

Read the full article: Turf Fertilization: Decreasing contamination of runoff

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