Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/1998
Publication Date: N/A
Interpretive Summary: Herbicide movement through soil may be influenced by placement, formulation, application rates, and tillage. In order to reduce potential herbicide movement through soil, these variables must be optimized in agricultural production systems. We found that banding the herbicides over the corn row reduced the total amount of herbicide applied and reduced the amount of herbicides leached through soil. It was also found that if weeds were not controlled between the rows by tillage, corn yields would be reduced. Therefore, banding soil applied herbicides limits the potential for herbicide leaching through soils. However, banding must be coupled with effective, timely cultivations, which may be a problem on heavier soil types. Weed species and their densities also should be considered prior to using banding techniques. Farmers can reduce herbicide use and movement through soil by a combination of herbicide application and cultivation practices.
Technical Abstract: Banding herbicide reduces chemical input compared to broadcast applications, and thereby reduces potential negative environmental impacts. This study evaluated the impact of three tillage systems (ridge-till, chisel plow, and moldboard plow) and two preemergence herbicide application methods (band and broadcast) on atrazine and alachlor movement, weed control, and corn yield in a loam and silty clay loam. A herbicide band applied over a corn row reduced herbicide input by 50-67 percent. Shallow cultivation was used for weed control between rows. Tillage did not impact herbicide movement, weed control or corn yield. Although less than 1 percent of the applied herbicide was detected in soil below 45 cm, atrazine and alachlor were found in water samples 90 cm below the surface. Banding reduced atrazine and alachlor collected in lysimeters by 50 and 80 percent respectively, compared to a broadcast application. However, atrazine levels sin some years increased from less than 0.1 (background) to a maximum of 0. ug L**-1 in a shallow aquifer below the silty clay loam. Corn yield was similar in band and broadcast treatments. In the silty clay loam, lower corn yields in banded than broadcast treatments in one out of the three years were attributed to poor weed control.