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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #116617
Title: HERBICIDE BANDING AND TILLAGE SYSTEM INTERACTIONS ON LOSSES OF THE HERBICIDES ALACHLOR AND CYANAZINE IN RUNOFF

Author
item HANSEN, N - UNIV OF MINN AG EXT SERV
item MONCRIEF, J - UNIV OF MINN AG EXT SERV
item GUPTA, S - UNIVERSITY OF MINNESOTA
item CAPEL, P - UNIVERSITY OF MINNESOTA
item Olness, Alan

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Herbicide loss from land applications either through erosion and surface runoff of rainfall or through leaching to the groundwater are environmental risks. Two commonly used herbicides, alachlor and cyanazine, were applied to corn fields on which three different tillage systems were applied. The loss of both herbicides in the surface runoff decreased with time after application. Concentrations of cyanazine decreased from about 1 part per million to about 1 part per billion. Concentrations of alachlor decreased from about 0.1 part per million to about 0.1 part per billion. Total losses of herbicide ranged from 0.1 to 1% of the alachlor applied and from 0.38 to 4.4% for the cyanazine applied. Tillage management and herbicide application methods are both effective tools in reducing losses of pesticides from soils. Ridge tillage consistently had the least total losses and moldboard plow tillage had the greatest total losses. Band applications of herbicides require less chemical and resulted in less tota movement from the site of application and contamination of the water. This study shows that producers will benefit economically by using band applications of herbicides and a ridge tillage system to reduce chemical loss and contamination of water.

Technical Abstract: Runoff from agricultural fields delivers sediment and pesticides to receiving surface waters. Pesticides are transported by runoff in solution phase and with eroded sediments. Conservation tillage reduces upland erosion and associated contaminant transport. However, losses of water soluble nutrients and pesticides may be high with conservation tillage unless the runoff volume is also reduced. Reducing herbicide application rates is another approach to minimize off-site transport. Herbicide banding can reduce herbicide application rates and costs by one-half or more. The objective of this study was to compare herbicide losses in runoff from plots with band or broadcast applied herbicides and to assess any interactions of banding with tillage practice. The herbicides alachlor and cyanazine were broadcast or band applied to plots managed in a moldboard plow, chisel plow, or ridge till system. When herbicides were broadcast applied, losses of alachlor and cyanazine in runoff followed the order: moldboard plow > chisel plow > ridge till. Conservation tillage systems reduced runoff and losses of herbicides but had no effect on herbicide concentration. Runoff losses from band treated plots were much smaller than for broadcast. Banding reduced both concentration of herbicides in runoff and total loss of herbicides by reducing runoff volume. Herbicide losses in the water phase averaged 88% of the total loss for alachlor and 97% for cyanazine. Cyanazine was more persistent than alachlor in the soil. Comparison of the residual cyanazine concentrations in soil with cyanazine concentrations in eroded sediments suggests that desorption of cyanazine from sediments suspended in runoff may be an important transport mechanism.