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United States Department of Agriculture

Agricultural Research Service

Research Project: Alternatives to MEBR for California Cropping Systems

Location: Water Management Research

Title: Minimize emission and improve efficacy with low permeability tarp in soil fumigation for perennials

Authors
item GAO, SUDUAN
item Qin, Ruijun -
item Cabrera, Alfonso -
item GERIK, JAMES
item Hanson, Bradley -
item Sosnoskie, Lynn -
item WANG, DONG
item BROWNE, GREG

Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: September 8, 2012
Publication Date: November 6, 2012
Citation: Gao, S., Qin, R., Cabrera, A., Gerik, J.S., Hanson, B.D., Sosnoskie, L., Wang, D., Browne, G.T. 2012. Minimize emission and improve efficacy with low permeability tarp in soil fumigation for perennials. International Conference on Methyl Bromide Alternatives and Emissions Reductions. p. 6-1 - 6-3..

Interpretive Summary: Interpretive Summary: Many orchards and nurseries depend on soil fumigation to disinfest soil to establish vigorous, productive, and healthy trees. However, fumigant emission control is mandatory in air quality non-attainment areas including the San Joaquin Valley (SJV) of CA where most tree fruits and nuts are produced. This research evaluated fumigation treatments for minimizing emissions and maximizing fumigant use efficiency by using a totally impermeable film (TIF) to tarp the soil after fumigation. In fall 2011, a comprehensive field trial was conducted in the SJV and VaporSafe™ TIF was tested on fumigant emission, distribution in soil, and efficacy on nematodes, pathogens, and weeds. Regular or carbonated (adding carbon dioxide to fumigant) Telone C35 was shank-injected to 45 cm depth and sealed with either no tarp, standard polyethylene PE tarp or TIF. Three rates (full, 2/3, and 1/3 rates) were tested under the TIF. The TIF reduced emissions >95% relative to bare soil while standard PE tarp reduced emissions ~30%. The total emission loss from TIF tarped plots was 2% of total applied for 1,3-D and <1% for CP. TIF significantly increased fumigant concentration or concentration-time exposure indices at 15 cm depth as compared to the PE film. Reduced 2/3 rate under TIF showed the possibility to provide nematode control as effectively as methyl bromide. Improvement on fumigant distribution by carbonation is inconclusive and requires more field tests. This research continues to develop management strategies to maximize fumigant efficiency while reducing negative environmental impact.

Technical Abstract: The San Joaquin Valley (SJV) of California is a major productive region for tree fruits, tree nuts and grapes. Orchards and open-field nurseries of these crops rely on soil fumigation to control soil-borne pests or replanting diseases in order to establish vigorous, productive, and marketable trees. However, emission control for major alternative fumigants to methyl bromide (MeBr), such as 1,3-dichloropropene (1,3-D) and chloropicrin (CP), is mandatory in air quality non-attainment areas including the SJV where most of the tree fruits, nuts, and grapes are produced. The main purpose of this research is to quantify fumigation treatments that minimize emissions and at the same time maximize fumigant use efficiency by using a totally impermeability film (TIF). In fall 2011, a comprehensive field trial was conducted in the SJV and VaporSafe™ TIF was tested on fumigant emission, distribution in soil, efficacy on nematodes, pathogens, and weeds, and the potential of using reduced fumigant rates. A total of 11 treatments were included: non-fumigated control, standard MeBr, two full rates under either no tarp or standard polyethylene (PE) tarp, four 2/3 rates (under no tarp, PE, TIF, or a carbonated fumigant (adding CO2 to fumigant) under TIF); and three 1/3 rates (under PE, TIF or a carbonated fumigant treatment under TIF). The fumigants were shank-injected to 45 cm depth. Emission data showed that TIF reduced emissions >95% relative to bare soil, a significant improvement over the ~30% emission reduction by PE. The total emission loss from TIF tarped plots was 2% of total applied for 1,3-D and <1% for CP. Monitored emissions beyond TIF tarp-edges in bare soil were low as well. TIF also increased fumigant concentration or concentration-time (CT) exposure indices at 15 cm depth compared to the PE film. Reduced 2/3 rate under TIF showed the possibility to provide nematode control as effectively as methyl bromide. Improvement on fumigant distribution by carbonation is inconclusive and requires on further tests.

Last Modified: 9/29/2014
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