ARS | Publication request: Surface Water Applications for Reducing Emissions from Telone C35: Their Effect on Weed Populations

Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 2, 2006
Publication Date: November 6, 2006
Citation: Shrestha, A., Gao, S., Trout, T.J. 2006. Surface Water Applications For Reducing Emissions From Telone C35: Their Effect On Weed Populations. 2006 Proceedings of International Research Conference on Methyl Bromide Alternatives, pg 116-1 - 116-3, Orlando, Florida.

Technical Abstract: Telone C35, a mixture of 1,3-dichloropropene (1,3-D) and chloropicrin (CP), is a promising alternative fumigant to methyl bromide in various cropping systems. However, it is essential to control fumigant emissions from Telone C35 to minimize negative environmental impacts. It has been found that tarping with available standard high density polyethylene (HDPE) plastic is not effective in reducing 1,3-D emissions while water seals (applying water to soil surface by sprinklers) can reduce 1,3-D emissions effectively. However, water applications can have implications for weed management as weed seeds would be subjected to hydrothermal processes that would affect their germination. The objective of this study was to determine weed populations in shank-applied Telone C35 field plots with treatments of water seals, plastic tarps (HDPE and virtually impermeable film or VIF), and a combination of water application and HDPE tarp. Results showed that a combination of pre-irrigation + HDPE + Telone C35 resulted in the best overall weed control. The major weeds observed were mallow (Malva sp.), pigweed (Amaranthus sp.), carpetweed (Mollugo verticillata), and shepherdspurse (Capsella bursa-pastoris). Water seals only, HDPE tarp, and VIF tarp had similar weed populations as the non-fumigated control plots. The pre-irrigation + HDPE tarp also reduced the generally difficult to control species such as mallow. Water applications after fumigation generally resulted in higher emergence of all these species except carpetweed. The results indicate that while searching for methods to reduce fumigant emissions, the effects on soil pest control need to be monitored.