Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2009
Publication Date: 10/13/2009
Citation: Moore, M.T., Kroger, R., Cooper, C.M., Cullum, R.F., Smith, S., Locke, M.A. 2009. Diazinon reduction and partitioning between water, sediment and vegetation in stormwater runoff mitigation through rice fields. Pest Management Science. 65: 1182-1188.
Interpretive Summary: Pesticides can runoff farm fields and contaminate rivers, lakes, and ponds near agricultural fields. Management practices to reduce this possibility are needed in the agricultural production landscape. The current study examined the use of post-harvest rice fields as constructed wetlands to clean pesticide runoff. Results demonstrated that post-harvest rice fields were more efficient than ponds without plants in reducing the amount of pesticide leaving the farm. This has implications for utilization of post-harvest fields as an additional management practice for pesticide mitigation during wet seasons.
Technical Abstract: Contamination of surface waters by pesticides is a growing concern in the United States and around the world. Innovative mitigation strategies are needed to remediate this potential environmental contaminant. One potential solution is diverting pesticide-laden drainage or surface water through post-harvest agricultural rice fields. With a hydroperiod, hydrosoil, and hydrophyte (rice stalk), these systems serve essentially as a type of constructed wetland. In both a summer and fall experiment, diazinon-amended water was diverted through two rice ponds at the University of Mississippi Field Station. Likewise, a non-vegetated control pond was amended with diazinon-laden water. Water, sediment, and plant samples were taken spatially and temporally to determine the distribution of diazinon within systems. Outflow diazinon concentrations were significantly (p<0.05) decreased from inflow in both vegetated ponds for both pre-harvest and post-harvest experiments. Although sorption to rice plants was minimal in the overall mass distribution of diazinon (1 – 3%), temporal data indicated diazinon concentrations reached the outflow sediment of the non-vegetated control twice as fast as in either vegetated (rice) system. In both vegetated systems, sediment diazinon concentrations decreased (77% and 100%) from inflow to outflow, while a decrease of < 2% was noted in the non-vegetated control. Diversion of pesticide contaminated water through post-harvest rice fields demonstrated potential as a low-cost, environmentally efficient mitigation practice. Studies on these systems are continuing to evaluate the optimal chemical retention time for rice field mitigation.