|BAKER JAMES L|
|TIERNEY DENNIS P|
|PETER C JOHN|
Submitted to: Clean Water Clean Environment 21st Century Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/5/1995
Publication Date: N/A
Technical Abstract: Buffer strips provide an area along the side of fields or within fields through which surface water flow is diverted before entering into a stream channel. The purpose of a buffer strip is to remove the sediment and contaminant load so that the water which enters the stream will be relatively clean. Previous research has shown that grass buffer strips remove up to 25% of the atrazine found in fields. There has been little research conducted on the mechanisms by which filter strips or buffer strips reduce the herbicide load and how effective different sized strips would be in reducing herbicide concentrations. These experiments were set up in central Iowa to evaluate the mechanisms of action on buffer strips composed of a brome grass waterway mixture. These studies were conducted both in natural rainfall and simulated rainfall conditions during 1993 and 1994. The herbicides being evaluated were atrazine, cyanazine, and metolachlor. Reductions under both simulated and natural rainfall were found to be near 40% of the inflow for all three herbicides. Under natural rainfall conditions there was a decrease in the inflow concentrations during the season because of the continued decline in the surface concentrations in the field areas. The mechanism for removal was adsorption of herbicides in the upper 2 inches of the soil surface. Efficiency of removal can be improved by increasing the time water stays within the buffer strip and managing the buffer strip to ensure that water from the field is distributed as uniformly as possible once it enters the buffer strip. Buffer strips can be used to decrease the potential for offsite movement of herbicides from fields.