Nutrient management on golf courses in Delaware
Date
2005
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Publisher
University of Delaware
Abstract
Golfing is one of the favorite past times of people in the United States, and this country has seen tremendous growth in the number of golf courses during the last two decades. To maintain healthy turf on these golf courses, significant amounts of fertilizers are applied each year. There is some concern, however, that the nutrients from these fertilizers could be causing negative impacts on surface and groundwater supplies. Some people also suggest that organic fertilizers (e.g., manure or compost) are .better. fertilizers than synthetic fertilizers. The study reported in this thesis had two objectives. The first objective was to monitor the concentrations of nitrogen (N) and phosphorus (P) in surface waters on three golf courses over a period of 18 months to identify trends in water quality, while the second objective was to evaluate the value of pelletized poultry litter (i.e., organic fertilizer) as a fertilizer for a golf course fairway. In the first study, surface water samples were taken either bi-weekly or monthly from six to ten points on three different golf courses. These water samples were filtered and immediately analyzed for nitrate, ammonium, and dissolved P concentrations. The results showed that ammonium concentrations were usually negligible on all three courses. Nitrate concentrations were usually either higher as the water entered the course compared to where it exited the course or there was no change between the entry and exit points. There was one sampling point that was consistently high in nitrate concentrations. Dissolved P concentrations, indicate little change between water entering and exiting the courses. Water in a pond at one course tended to have relatively high concentrations of dissolved P that were likely caused by either surface runoff of P or high P concentrations in the pond sediments. Overall, there was no evidence that management practices at these three golf courses were adding significant concentrations of nutrients to the water; and in fact, there was evidence to suggest that nitrate concentrations were being decreased. In the second study, three types of fertilizers were evaluated as N sources for turf: pelletized poultry litter (4-2-3), milorganite (6-2-0), and a commonly used sulfur-coated urea fertilizer (32-5-7). This evaluation included monitoring turf growth, turf color, and nutrient concentrations for a period of two years. The fertilizers were applied at multiple rates in both the spring and the fall of each year. Turf clippings were collected after each mowing and weighed and then analyzed for nutrient concentrations. The results showed that the pelletized poultry litter resulted in a similar turf response as milorganite when applied at the same rate of N. The results also showed that it took about twice as much of the pelletized poultry litter and milorganite fertilizers to get the same N response as the synthetic fertilizer. There was no evidence that nitrate was leaching through the soil with any of these fertilizers. Overall, these results indicate that the synthetic fertilizer would be a more economical fertilizer than either the milorganite or pelletized poultry litter fertilizers.