Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: EFFECT OF SURFACE TARP ON EMISSIONS AND DISTRIBUTION OF DRIP-APPLIED FUMIGANTS

Authors
item Papiernik, Sharon
item Yates, Scott
item Dungan, Robert
item Lesch, Scott - UC RIVERSIDE, CA
item Zheng, Wei - UC RIVERSIDE, CA
item Guo, Mingxin - UC RIVERSIDE, CA

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 11, 2004
Publication Date: August 15, 2004
Citation: Papiernik, S.K., Yates, S.R., Dungan, R.S., Lesch, S.M., Zheng, W., Guo, M. 2004. Effect of surface tarp on emissions and distribution of drip-applied fumigants. Environmental Science and Technology. 38(16):4254-4262.

Interpretive Summary: Soil fumigants are used to control a wide variety of soil-borne pests in high-cash-value crops. Because of their high volatility, a large fraction of the fumigant applied to soil can be emitted from the soil surface, resulting in air contamination and decreased pest control efficacy. Application of soil fumigants through drip irrigation systems is receiving increasing attention. These experiments were conducted to determine the atmospheric emissions and soil distribution of fumigants following subsurface drip application, and the effect of the type of plastic soil cover on fumigant emissions in these systems. Cumulative emissions of the fumigant compounds 1,3-dichloropropene (1,3-D), methyl isothiocyanate (MITC), and propargyl bromide (PrBr) were relatively low, amounting to <10 percent of the applied mass. Tarping the bed with virtually impermeable plastic film (VIF) rather than the standard high-density polyethylene (HDPE) decreased cumulative emissions by more than 60 percent. When a VIF was used, a large fraction of the fumigant flux was from the untarped furrows, indicating that inhibiting volatilization from the bare furrow will be important in further reducing emissions in these systems. Monitoring the fumigant distribution in soil indicated that fumigant concentrations in the soil were higher under the VIF tarp. These results show that applying fumigants by subsurface drip irrigation and covering the soil surface with a VIF has the potential to increase pest control efficacy and decrease air contamination by pesticides.

Technical Abstract: Soil fumigants are used to control a wide variety of soil-borne pests in high-cash-value crops. Application of soil fumigants through drip irrigation systems is receiving increasing attention as a method to increase the uniformity of fumigant application. Little information is available on the emissions and soil distribution of fumigants following subsurface drip application, or the effect of plastic tarp on fumigant emissions in these systems. In these experiments, the fumigant compounds 1,3-dichloropropene (1,3-D), methyl isothiocyanate (MITC), and propargyl bromide (PrBr) were applied to soil beds via drip irrigation at 15 cm depth. Beds were tarped with either standard 1-mil high-density polyethylene (HDPE) or a virtually impermeable film (VIF), leaving the furrows bare. Cumulative emissions of 1,3-D, MITC, and PrBr in these tarped bedded systems was very low, amounting to <10 percent of the applied mass. These experiments were conducted in the winter months, with average air temperatures of 12 to15 C. Tarping the bed with VIF rather than HDPE resulted in a decrease in cumulative emissions of 60 percent. A large fraction of the 1,3-D and PrBr flux was from the untarped furrows in VIF-tarped plots, indicating that inhibiting volatilization from the furrow will be important in further reducing emissions in these systems. Monitoring the fumigant distribution in soil indicated that tarping the bed with VIF resulted in a much more effective containment of fumigant vapors compared to use of a HDPE tarp.

Last Modified: 9/1/2014
Footer Content Back to Top of Page