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Predicting Runoff and Associated Nitrogen Losses from Turfgrass using the Root Zone Water Quality Model (RZWQM)
Author(s) -
Schwartz Liliana,
Shuman Larry M.
Publication year - 2005
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0350
Subject(s) - surface runoff , environmental science , hydrology (agriculture) , irrigation , water quality , cynodon dactylon , nitrate , dns root zone , agronomy , soil water , soil science , ecology , biology , geology , geotechnical engineering
Nitrogen fertilizers are used to maintain optimum turfgrass quality, but off‐site movement of this primary nutrient can affect water quality. We conducted a 4‐yr study (1998–2001) designed to measure nitrate N runoff from turfgrass, gathering data to be used in the model. The process‐based Root Zone Water Quality Model (RZWQM) was used to predict nitrate associated with runoff from turfgrass. The measurements were made on 12 sloped (5%), 25‐m 2 plots of ‘Tifway’ bermudagrass [ Cynodon dactylon (L.) Pers.], managed as golf course fairways and exposed to natural and simulated rainfall. Surface runoff volume and nitrate N loads were monitored after applying simulated rainfall at an average intensity of 27.4 mm h −1 The irrigation occurred (25 or 50 mm) 4 through 168 h after treatment with various rates of N fertilizers for 1998–2001. RZWQM adequately simulated water runoff volumes (<19%; nonsignificant, paired t test) in the first three (normal or wet) years, but overpredicted (70%) in the fourth, dry year. RZWQM overpredicted nitrate N loads by a factor of 1.3 for the first three years (nonsignificant), and by a factor of almost 6 for the fourth year (highly significant). These overpredictions occurred when the runoff volumes and N loads were very small. The research has shown that refinements to RZWQM are needed for turfgrass management applications.