Modeling Evaluation of Alternative Management Practices and Reclaimed Water for Turfgrass Systems

Abstract

AbstractThe use of reclaimed water for turfgrass irrigation is being implemented to conserve potable water supplies. Reclaimed water coupled with alternative management strategies may reduce offsite loadings of fertilizers and pesticides. The Environmental Policy Integrated Climate (EPIC) water quality model was used to evaluate alternative management practices and reclaimed water for a southern turfgrass system. One green and fairway were modeled for a 65‐yr period of climatic record with four treatments. Specifically, the treatments were normal water normal management (NWNM), normal water reduced management (NWRM), reclaimed water normal management (RWNM), and reclaimed water reduced management (RWRM). Surface and subsurface nitrate (NO3‐N), fenamiphos (ethyl 3‐methyl‐4‐(methylthio)phenyl (1‐methylethyl)phosphoramidate), and MSMA (monosodium methanearsonate) losses were evaluated. Significant differences were predicted in NO3‐N runoff and leachate losses from green management. Mean annual NO3‐N losses from runoff were 2.85 kg ha−1 (NWNM) and 2.05 kg ha−1 (RWRM). Significant reductions in mean annual surface and subsurface NO3‐N losses from fairway conditions were simulated when comparing NWNM (5.11 kg ha−1 surface; 1.68 kg ha−1 subsurface) to RWRM (2.69 kg ha−1 surface; 0.90 kg ha−1 subsurface). The cited differences in NO3‐N losses in runoff and leachate from green and fairway conditions were attributed primarily to irrigation strategies and excess rainfall. Predicted average annual pesticide recovery in runoff and leachate was <0.01% of applied and no significant differences were predicted with respect to treatments. This modeling strategy provides valuable insight into the relative efficacy of implementing reduced management practices for turfgrass systems.