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United States Department of Agriculture

Agricultural Research Service

Title: Distribution and Dissipation of 1,3-D and Chloropicrin after Shank and Drip Applications in a Clay Loam Soil

Authors
item Gao, Suduan
item Trout, Thomas
item Schneider, Sally
item Ajwa, Husein - UC-DAVIS
item Browne, Greg

Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 8, 2004
Publication Date: October 31, 2004
Citation: Gao, S., Trout, T.J., Schneider, S.M., Ajwa, H., Browne, G.T. 2004. Distribution and dissipation of 1,3-d and chloropicrin after shank and drip applications in a clay loam soil. Proceedings of International Research Conference on Methyl Bromide Alternatives, pp 801-804.

Interpretive Summary: Soil conditions (e.g., texture and water content) and use of tarps affect fumigation efficacy in controlling soil pests and emissions. Research has found that standard HDPE is not an effective barrier for 1,3-D and high soil moisture is more effective in reducing emission than HDPE. High soil moisture may, however, cause poor distribution of fumigants in soils. Research is needed on effective combination of fumigation methods and use of tarps that maximizes fumigation efficacy while minimizing emissions in field conditions. The objectives of this study were to determine the effect of shank injection and drip application on fumigant distribution and dissipation of 1,3-D and chloropicrin (CP) in a clay loam soil in the San Joaquin Valley, California and to determine the effect of plastic tarp (HDPE and VIF) on fumigant distribution and dissipation. In a field trial of comparing the efficacy of fumigation methods with tarps, three treatment plots: shank injection with HDPE, shank injection with VIF, and drip application with HDPE, were chosen for monitoring fumigant concentration changes in soil gas and liquid/solid phases. Telone C-35 and Inline were used in shank injection and drip application, respectively, at a rate of 544 lb/A. The soil type is Yokohl clay loam (fine, montmorillonitic, thermic family of Typic Durixeralfs) with a cemented iron-silica duripan at about 60 cm depth. Fumigant concentrations below this depth were extremely low throughout the monitoring for all treatments. This indicates that downward movement of fumigants was inhibited. Distribution of 1,3-D and CP are similar in both gas phase and soil liquid/solid phase with generally higher concentrations in shank injection plots than in the drip application plot. The plot with VIF tarp showed higher concentrations in the gas phase but lower concentrations in the liquid/solid phase than the plot with HDPE. Peak concentrations were observed within 24 h for shank applications and these peaks were extended to 72 h for drip applications. Results indicate that presence of duripan, soil water content (through shank injection and drip application), and use of plastic tarps all influence fumigant distribution and dissipation. More work is needed to develop practical fumigation methods that maximize fumigation efficacy and minimize detrimental impact to the environment.

Technical Abstract: Soil conditions (e.g., texture and water content) and use of tarps affect fumigation efficacy in controlling soil pests and emissions. Research has found that standard HDPE is not an effective barrier for 1,3-D and high soil moisture is more effective in reducing emission than HDPE. High soil moisture may, however, cause poor distribution of fumigants in soils. Research is needed on effective combination of fumigation methods and use of tarps that maximizes fumigation efficacy while minimizing emissions in field conditions. The objectives of this study were to determine the effect of shank injection and drip application on fumigant distribution and dissipation of 1,3-D and chloropicrin (CP) in a clay loam soil in the San Joaquin Valley, California and to determine the effect of plastic tarp (HDPE and VIF) on fumigant distribution and dissipation. In a field trial of comparing the efficacy of fumigation methods with tarps, three treatment plots: shank injection with HDPE, shank injection with VIF, and drip application with HDPE, were chosen for monitoring fumigant concentration changes in soil gas and liquid/solid phases. Telone C-35 and Inline were used in shank injection and drip application, respectively, at a rate of 544 lb/A. The soil type is Yokohl clay loam (fine, montmorillonitic, thermic family of Typic Durixeralfs) with a cemented iron-silica duripan at about 60 cm depth. Fumigant concentrations below this depth were extremely low throughout the monitoring for all treatments. This indicates that downward movement of fumigants was inhibited. Distribution of 1,3-D and CP are similar in both gas phase and soil liquid/solid phase with generally higher concentrations in shank injection plots than in the drip application plot. The plot with VIF tarp showed higher concentrations in the gas phase but lower concentrations in the liquid/solid phase than the plot with HDPE. Peak concentrations were observed within 24 h for shank applications and these peaks were extended to 72 h for drip applications. Results indicate that presence of duripan, soil water content (through shank injection and drip application), and use of plastic tarps all influence fumigant distribution and dissipation. More work is needed to develop practical fumigation methods that maximize fumigation efficacy and minimize detrimental impact to the environment.

Last Modified: 11/27/2014
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