Leaching of Phosphate and Nitrate from Simulated Golf Greens (Poster)
Shuman, Larry M.
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Fertilizer nutrients can leach from porous golf greens potentially causing degradation of surface water quality through eutrophication. A greenhouse experiment was carried out with 52 cm columns (15 cm diam.) made to US Golf Association green specifications and sodded to bermudagrass to determine the effects of fertilizer sources at various rates on P and N leaching. Fertilizer sources were a soluble salt solution and a granular controlled-release product. Four fertilizer rates were applied each week for 6 weeks. Irrigation rates were 0.63 cm per day initially and increased to 1.25 cm per day at week 7. Weekly leachate collections were analyzed for P and NO₃₋N concentrations and volume of the leachate was measured. Concentrations of N and P were lower in the leachate for the granular source than for the soluble source. Leaching of P continued for the entire 23 weeks of the experiment, whereas N was essentially exhausted by week 15 indicating that P leaches at a slower rate than N. For the low P rate (5 kg/ha) for the granular controlled-release source there was no increase in P concentration in the leachate compared to control. Thus, low P rates will not result in degradation of water quality due to increased P. Results show that P leaching is a potential problem only at high rates of soluble sources and high irrigation, whereas N is more readily leached.