Surface transport of 2,4-D from small turf plots: observations compared with GLEAMS and PRZM-2 model simulations
✍ Scribed by Ma, Qing Li; Smith, Albert E; Hook, James E; Bridges, David C
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 225 KB
- Volume
- 55
- Category
- Article
- ISSN
- 1526-498X
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✦ Synopsis
A three-year üeld study was conducted using twelve 7.4  3.7 m plots and simulated rainfall to investigate pesticide run-oþ following application to a golf course fairway. The plots were sprigged with 'Tifway 419' bermudagrass (Cynodon dactylon  C transvaalensis). The dimethylamine salt of 2,4-D [ (2,4-dichlorophenoxy)acetic acid ] was applied as foliar sprays at a rate of 2.24 kg AI ha-1. Simulated rainfall was applied at an intensity of 29 mm h-1 one day before and 1, 2, 4, and 8 days after the pesticide applications for 0.92, 1.75. 1.75, 0.92, and 0.92 h, respectively. Water run-oþ was measured using a tipping-bucket apparatus and sub-samples were analyzed for pesticide residues. Data collected from the study were also compared with the GLEAMS and PRZM-2 model simulations for surface water and 2,4-D run-oþ . Mass and concentration of 2,4-D in run-oþ decreased rapidly, with 74.5% of the total run-oþ of 2,4-D occurring in the ürst run-oþ event after treatment. When calibrated to the site-speciüc characteristics, the GLEAMS and the PRZM-2 models adequately simulated the average of surface water run-oþ over all plots, with normalized root mean square error (NRMSE) and coefficient of determination for linear regression (R2) being 22.8% and 0.917 for GLEAMS, and 23.7% and 0.879 for PRZM-2, respectively. However, both GLEAMS (NRMSE = 82.1% , R2 = 0.776) and PRZM-2 (NRMSE = 125.8% , R2 = 0.513) less accurately simulated 2,4-D concentrations in run-oþ .