Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2005
Publication Date: 1/12/2006
Citation: King, K.W., Hughes, K.L., Balogh, J.C., Fausey, N.R., Harmel, R.D. 2006. Nitrate-nitrogen & dissolved reactive phosporus in subsurface drainage from managed turfgrass. Journal of Soil and Water Conservation. 61(1):31-40. Interpretive Summary: Turf systems, including golf courses, turf farms, city parks, residential and institutional lawns, and roadsides are an integral component of the landscape. Yet, quantitative information about nutrients that exit turfgrass systems in subsurface drainage is limited. Losses of nitrogen and phosphorus measured in the drainage water were between 2 and 3% of the amount applied. The timing and amount of nutrient losses were dependent on application date and climate. Urban managers, planning commissions, regulatory authorities, and individuals or entities involved in water quality assessment as it relates to Total Maximum Daily Load (TMDL)s, source water protection, or other environmental legislation will benefit from the research by having the ability to make scientifically sound decisions regarding environmental policy related to turfgrass systems.
Technical Abstract: Recent evidence suggests that turfgrass nutrients in runoff and subsurface flow pose potential risks to surface water quality. Research on water quality associated with turfgrass has generally focused on surface runoff, not subsurface flows. Quantifying the delivery of nutrients, nitrate nitrogen (NO3-N) and dissolved reactive phosphorus (DRP), to streams from subsurface drainage features on managed turf sites, and relating the transport to fertility management and season is important for many urban managers, especially those under regulatory scrutiny. NO3-N and DRP concentrations from two French drains located on the Morris Williams’ Municipal Golf Course in Austin, TX, were measured over a 4-year period (March, 1999 to March, 2003). Time series statistics were used to analyze and relate NO3-N and DRP concentrations to weather and management. A weak statistical relationship (r2 = 0.55) was detected between discharge and NO3-N concentration at one of the two drains. The relationship between discharge and DRP concentration was not significant. Median NO3-N concentrations from the two drains were 1.27 mg L-1 and 0.32 mg L-1. NO3-N loading from the drains was 2.7 kg ha-1. The NO3-N concentrations and load from the turf area were approximately 10% of those values reported for typical row crop agriculture. Median DRP concentrations were 0.11 mg L-1 and 0.09 mg L-1 while DRP loading was 0.46 kg ha-1. Significant (' = 0.05) seasonal tendencies were found with respect to NO3-N and DRP. A strong correlation was evident between the timing of peak NO3-N losses and nitrogen application; and between the timing of peak NO3-N losses and air temperature. There was a similar correlation between the timing of peak DRP losses and phosphorus application. Our results suggest NO3-N transport in subsurface drainage from this golf course is not a water quality issue. However, our findings suggest significant DRP transport through the drains and a need for an integrated (turf, nutrients, and water) management plan that includes consideration of subsurface drainage fluxes.