2012 Annual Report
Objective 1a. Conduct Laboratory Experiments and Modeling Studies to Test Accuracy of Simplified Approaches for Estimating Fumigant Emissions. Objective 1b. Determine the Effect of Fumigant Exposure and Soil Temperature on Survival of Nematodes, Fungi, and Weed Seeds. Objective 1c. Develop and Test a Model to Predict Fumigant Fate and Transport and Survival of Nematodes, Fungi, and Weed Seeds after Soil Fumigation.
Objective 2: Develop and test new management practices to reduce contamination while controlling plant pests in strawberry and vegetable production.
For objective 1b, experiments were conducted as needed to provide survival data for use in interpreting the field and laboratory experiments.
For objective 1c, a process-based mathematical model was used to assess the effects of plastic film type, application depth, bed width, and furrow treatment on emission reduction and pest control using the experimental configuration from the FY11 field study. The simulations were carried out using Hydrus-2D, modified to include various fumigant-related processes; such as temperature dependent properties of the surface tarp, tarp removal at a specified time, and different surface conditions. A comparison between the simulated and experimentally measured results was made for the period-averaged emission rates and cumulative emissions under high density polyethylene film (HDPE) and virtually impermeable film (VIF). Next, the model was extended to simulate other scenarios including different application depths (5, 10, 15, and 20 cm), bed widths (50, 100 and 150 cm), and furrow treatments (depths of buried film, and with and without a reagent). The concentration-time values were also calculated to assess pest control efficacy. These findings will be further analyzed to help in optimizing the fumigant application to maintain efficient pest control and minimizing negative environmental effects.
For objective 2, The field data collected in the previous (FY11) experiment was analyzed to determine the effectiveness of combining soil heating and reduced application of soil fumigants (Telone Inline) for controlling soil pests and pathogens. Three treatments were studied: a reduced application rate (70% of standard rate) of Telone Inline was applied to raised soil beds covered with high-density polyethylene film (HDPE), thermic film (Thermic), or virtually impermeable film (VIF). The results show that the Thermic treatment had the highest emission rate and the VIF treatment the lowest (<5% of Thermic). Soil pests were best controlled using VIF film, since soil heating was similar to the other treatments and fumigant concentrations (i.e., exposure) were highest under VIF. The findings demonstrate that both the film permeability and entrapped heat synergistically affect soil organism survival and should be considered together when developing new improved fumigation methods.
Zheng, W., Li, X., Yates, S.R., Bradford, S.A. 2012. Anaerobic transformation kinetics and mechanism of steroid estrogenic hormones in dairy lagoon water. Environmental Science and Technology. 46(10):5471-5478.
Zheng, W., Yates, S.R., Papiernik, S.K. 2008. Transformation kinetics and mechanism of the sulfonylurea herbicides pyrazosulfuron ethyl and halosulfuron methyl in aqueous solutions. Journal of Agriculture and Food Chemistry. 56:7367-7372.
Yates, S.R., Mcconnell, L.L., Hapeman, C.J., Papiernik, S.K., Gao, S., Trabue, S.L. 2011. Managing agricultural emissions to the atmosphere: State of the science, fate and mitigation, and identifying research gaps. Journal of Environmental Quality. 40(5):1347-1358.
Yuan, S., Wang, Q., Yates, S.R., Petterson, N.G. 2010. Development of an efficient extraction method for oxytetracycline in animal manure for high performance liquid chromatography analysis. Journal of Environmental Science and Health. 45(7):612-620.
Li, X., Zheng, W., Machesky, M.L., Yates, S.R., Katterhenry, M. 2011. Degradation kinetics and mechanism of antibiotic ceftiofur in recycled water derived from beef farm. Journal of Agricultural and Food Chemistry. 59:10176-10181.
Papiernik, S.K., Yates, S.R., Chellemi, D.O. 2011. A standardized approach for estimating the permeability of plastic films to soil fumigants under various field and environmental conditions. Journal of Environmental Quality. 40:1375-1382.
Wang, D., Yates, S.R., Gao, S. 2011. Chloropicrin emissions after shank injection: Two-dimensional analytical and numerical model simulations of different source methods and field measurements. Journal of Environmental Quality. 40:1443-1449.
Gao, S., Hanson, B.D., Qin, R., Wang, D., Yates, S.R. 2010. Comparisons of surface sealing methods in emission reduction from soil fumigation using field plot tests. Journal of Environmental Quality. Available on line: Nov 2010, doi:10.2134/jeq2009.0422.