Location: Contaminant Fate and Transport ResearchTitle: Effect of films on 1,3-dichloropropene and chloropicrin emission, soil concentration, and root-knot nematode control in a raised bed) Author
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2013
Publication Date: 3/5/2013
Publication URL: http://www.ars.usda.gov/SP2UserFiles/Place/53102000/pdf_pubs/P2419.pdf
Citation: Luo, L., Yates, S.R., Ashworth, D.J., Xuan, R., Becker, O. 2013. Effect of films on 1,3-dichloropropene and chloropicrin emission, soil concentration, and root-knot nematode control in a raised bed. Journal of Agricultural and Food Chemistry. 61:2400-2406. Interpretive Summary: Besides containing fumigants in the soil, tarps also greatly impact soil temperature, which can be an important and synergistic factor for controlling soil-borne pests. However, the effect of fumigation films on increasing soil temperature and improving pest control is often neglected when developing fumigant emission reduction methods. Additionally, temperature also influences fumigant transport and fate. The objective of this study was to determine the ability of different types of films with varying permeability and thermal properties to reduce atmospheric emission losses of 1,3-dichloropropene (1,3-D) and chloropicrin, retain them in soils, and aid parasitic nematode control at a reduced-rate of fumigation. The findings imply that not only the film permeability but the synergistic ability to entrap heat should be considered when developing new improved films for fumigation. This research will help growers to meet future regulations on fumigant emissions.
Technical Abstract: Soil fumigation is an important component of U.S. agriculture, but excessive emissions can be problematic. The objective of this study was to determine the effects of agricultural films (e.g., tarps) on soil fumigant atmospheric emissions and spatiotemporal distributions in soil, soil temperature, and plant pathogen control in the field using plastic films with various permeabilities and thermal properties. A reduced rate of 70% InLine (60.8% 1,3-dichloropropene (1,3-D) and 33.3% chloropicrin (CP)) was applied via drip line to raised soil beds covered with standard high-density polyethylene film (HDPE), thermic film (Thermic), or virtually impermeable film (VIF). 1,3-D and CP emission rates were determined using dynamic flux chambers, and the concentrations in soil were measured using a gas sampler. The pest control efficacy for the three treatments was determined using bioassay muslin bags containing soil infested with citrus nematodes (Tylenchulus semipenetrans). The results show that the Thermic treatment had the highest emission rates, followed by the HDPE and VIF treatments, and the soil concentrations followed the reverse order. In terms of pest control, covering the beds with thermic film led to sufficient and improved efficacy against citrus nematodes compared to standard HDPE film. Under HDPE, >20% of nematodes survived in the soil at 30 cm depth at day 12. The VIF treatment substantially reduced the emission loss from the bed (2% of the Thermic and 6% of the HDPE treatments) and eliminated plant parasitic nematodes because of its superior ability to entrap fumigant and heat within soils. The findings imply that not only the film permeability but also the synergistic ability to entrap heat should be considered in the development of new improved films for fumigation.