Prevent Phosphorus from Leaving the Golf Course

Figure Caption: The diagram depicts the trend between annual dissolved reactive phosphorous (DRP) and total phosphorous (TP) concentrations in water (ppm or mg/L) compared to the amount of elemental phosphorous applied to the golf course(lbs./acre). The values for DRP and TP are the amounts found in runoff and drainage water leaving the golf course property. We now know from several years of environmental research that turfgrass soils tend to accumulate phosphorous fertilizer. It is very important to only apply fertilizers with phosphorous if a soil test indicates there is a deficiency for maintaining active turfgrass growth.

Fertilizers nutrients can sometimes find their way into runoff and drainage water. The H-flume installed at Northland Country Club in Duluth, Minn. was part of a research project to examine the amount of phosphorous and nitrogen in water leaving the golf course.

Golf course managers recognize the importance of keeping fertilizer nutrients on the golf course and preventing offsite movement into surface waters such as streams, reservoirs, and lakes. For the past decade, the USGA has supported research by the US

Department of Agriculture to examine the environmental impact of golf courses on surface water. Seasonal variations in nutrient concentrations of nitrogen and phosphorous were found in runoff and drainage water leaving the golf course. In fresh water systems, the small nitrogen concentrations in water leaving the golf course are less important than they are in saltwater systems. However, phosphorus concentrations found in surface and drainage water exiting the course are problematic in both fresh and saltwater systems. Excess amounts of phosphorous can cause the ‘eutrophication’ of a body of water, or water that has increased algal growth and reduced amounts of dissolved oxygen for fish.

Nitrogen and phosphorous nutrients leaving a golf course are affected by the amount of seasonal rainfall or irrigation, fertilizer application timing and rate, as well as seasonal turfgrass growth. Daily concentrations of nutrients in golf course water samples were generally less than concentrations from other land uses; however, the total yearly losses were similar. Adopting Best Management Practices (BMPs) aimed at reducing the offsite movement of nutrients will reduce the environmental impact of golf courses. With respect to nutrients, nitrogen and phosphorus, the recommended BMPs are:

· Follow soil test recommendations and reduce application rates

· Use slow release or organic formulations for large areas

· Move fertilizer nutrients into the thatch and soil by ‘light’ irrigation after application

· Time nutrient applications to coincide with turf needs

· Avoid an application if rainfall is expected within 48 hours

· Avoid late fall applications, especially on dormant turfgrass

· Monitor irrigation practices in relation to fertilizer applications (do not promote tile flow)

· Make multiple, low-dose applications rather than a few large applications

· Install buffers around streams and ponds

· Route drainage waters through wetlands to filter out nutrients

Further information can be found at:

Golf Course Watershed Management for Reduction Nutrient and Pesticide Losses to Surface Water