Leaching Potential of Msma In Bermudagrass Turf.

Experiments were conducted at the Plant and Soil Science greenhouses in Lubbock, TX during spring of 2012. Pots (30 cm diameter, 0.03 yd³) were lined with 20x20 mesh screen and filled with sandy clay loam or sand soil. ‘Tifsport’ hybrid bermudagrass sod (10-years old) was cut to a depth of 5 cm, washed of all soil, and transplanted into pots on February 27, 2012. Sod was placed flush with the edge of each pot and maintained at a height of 0.6 cm. A starter fertilizer (7N-7P₂O₅-7K₂O) was applied at transplant at a rate of 24 kg N ha^-1. Greenhouse temperatures were maintained at 34/26 C (day/night) with average midday solar radiation ranging from 636 to 754 µmol m^-2 s^-1. Irrigation (3.8 cm of water wk^-1) was supplied through an overhead irrigation system. Soil and water samples were taken prior to trial initiation and analyzed for background arsenic levels. Bermudagrass grew and acclimated in the greenhouse for one month. MSMA (2.5 kg ai ha^-1) was applied on April 3, 2012 with a CO₂ backpack sprayer equipped with XR8004VS nozzles calibrated to deliver 375 L ha^-1 at 221 kPa. Leachate was collected 1, 3, 7, and 14 days after treatment (DAT); and analyzed for As^III, As^V, monomethylarsonic acid (MMA), and dimethlyarsinic acid (DMA). As^III and MMA concentrations of 27 to 97 and 20 to 89 ppb, respectively, were recorded for several sandy clay loam leachates 1 DAT. Concentrations were 12 to 19 and 11 to 12 ppb, respectively, 3 DAT. As^V and DMA concentrations of 12 to 66 and 15 to 179 ppb, respectively, were recorded for several sand leachates 7 DAT. As^III, As^V, MMA, and DMA concentrations of 12 to 30, 14 to 96, 13 to 288, and 32 to 73 ppb, respectively, were recorded for several sand leachates 14 DAT.