Effects of Manure and Water Applications on 1,3-Dichloropropene and Chloropicrin Emissions in a Field Trial

United States Department of Agriculture-Agricultural Research Service, Water Management Research Unit, San Joaquin Valley Agricultural Sciences Center, Parlier, California 93648, USA.
Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 06/2009; 57(12):5428-34. DOI: 10.1021/jf900245f
Source: PubMed


Minimizing fumigant emissions is required for meeting air-quality standards. Application of organic materials to surface soil has been effective in reducing fumigant emissions during laboratory tests, but the potential to reduce emissions in the field has not been adequately evaluated. The objective of this study was to determine the effect of incorporated composted manure with or without water applications on fumigant emissions and the potential impact on pest control efficacy under field conditions. Treatments included a bare-soil control, composted dairy manure at 12.4 and 24.7 Mg ha(-1), postfumigation intermittent water seals (11 mm water irrigated immediately following fumigation and 4 mm at 12, 24, and 48 h), and incorporation of manure at 12.4 Mg ha(-1) combined with the water seals or a high-density polyethylene (HDPE) tarp. Telone C35 was shank-applied at 553 kg ha(-1), and emissions of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) were monitored for 10 days. The results indicate that there was no significant difference in emission peak flux and cumulative emission loss between the control and the 12.4 Mg ha(-1) manure treatment. The higher manure rate (24.7 Mg ha(-1)) resulted in lower emission flux and cumulative emission loss than 12.4 Mg ha(-1), although the differences were only significant for CP. In contrast, the water treatments with or without manure incorporation significantly reduced peak emission rates (80% reduction) and cumulative emission loss ( approximately 50% reduction). The manure + HDPE treatment resulted in the lowest CP emissions but slightly higher 1,3-D emissions than the water treatments. Reductions in peak emission from water treatments can be important in reducing the potential acute exposure risks to workers and bystanders. This research demonstrated that incorporation of composted manure alone did not reduce fumigant emissions and effective emission reduction with manure amendment may require higher application rates and/or more effective materials than those used in this study.

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    • "It is not clear why manure amendment sealed with HDPE film would limit downward movement of the fumigants; however, this observation may have been due to the effects of manure on surface soil temperature and film permeability (Gao et al., 2009). In the 2007 trial, intermittent water seals reduced cumulative 1,3-D emissions similar to HDPE plots (Gao et al., 2009) and no differences in nematode control or weed biomass were noted. Differences in pest control between the 2006 and 2007 trials not obviously due to surface seal treatments may have been due to slight differences in soil conditions and application techniques. "
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    ABSTRACT: The phase-out of methyl bromide for preplant soil fumigation has resulted in an increased reliance on combinations of 1,3-dichloropropene and chloropicrin in many annual and perennial cropping systems in California. However, these fumigants also can have negative environmental and human health consequences and considerable research has been conducted on methods to minimize emission of these products from the soil to the atmosphere. To ensure that pest control efficacy is not compromised by emission reduction techniques, this research was conducted to simultaneously evaluate the effects of several surface seal techniques on fumigant emissions and the efficacy of soil-borne pest control with a mixture of 1,3-dichloropropene + chloropicrin. Results indicated that the interaction between emission reduction techniques and pest control efficacy can be complicated. For example in the 2006 trial, some surviving nematodes were observed in plots with both high (manure plus high density polyethylene film) and intermediate (pre-irrigation) 1,3-D cumulative emissions which suggested that emission loses are not solely responsible for some pest control failures. Weed control tended to be better with plastic film treatments and worse with pre-fumigation soil moisture manipulations but was affected less than expected by intermittent water seals. Although pest control clearly was affected by surface seal techniques, especially in shallow soil layers, some differences in nematode and weed control could not be explained solely by surface seals. These results underline the complex interactions among soil moisture and other environmental factors, application techniques, and emission reducing surface seal treatments. As new techniques and technologies become available to reduce fumigant emissions, we recommend that research include pest control efficacy evaluations before any emerging techniques are required by regulators or implemented by growers.
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    • "Emission sampling in all field trials was carried out using dynamic flux chambers by trapping the fumigants on either charcoal (for 1,3-D only) or XAD (for both 1,3-D and CP) sampling tubes. Some information about these chambers was provided in Gao et al. (2008) The samples were extracted and analyzed for the fumigants following similar procedures reported earlier (e.g., Gao et al., 2009). Both emission flux and cumulative emission loss were computed. "
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    ABSTRACT: Emission measurement has been an important component for the first two years of the Pacific Area-Wide (PAW) Pest Management Program for Integrated Methyl Bromide Alternatives. Dynamic Flux Chamber Systems with continuous and auto-sampling features were used for the emission sampling. Data collected as a part of this project has lead to several important conclusions. However, overestimation of cumulative emissions from bare soil has occasionally been observed and a number of methods for resolving this problem have been proposed and some were tested in the field. Reported here are emission data summaries from 2007 and 2008 field trials. OBJECTIVES: This project was to support emission monitoring for three PAW projects (industry sectors including perennial nursery, almond/stone fruits and grapevine orchards) under the Pacific Area-Wide Pest Management Program. The objective was to determine the effects of various surface sealing techniques or treatments as well as fumigation methods that are applicable for different commodities on fumigant emissions. Fumigants studied thus far included mainly 1,3-dichloropropene (1,3-D) and chloropicrin (CP). STUDY METHODS: Three field fumigation trials were conducted each year in 2007 and 2008 near Parlier at either USDA-ARS San Joaquin Valley Agricultural Sciences Center or University of California Kearney Agricultural Center. The soil was Hanford sandy loam (coarse-loamy, mixed, superactive, nonacid, thermic Typic Xerorthents). The trials were conducted in the months of August through November. The fields were usually cultivated to 75 cm depth and irrigated two weeks before fumigation to achieve adequate soil moisture conditions for fumigation. Each trial included efficacy studies by other scientists and only selected treatments were monitored for emissions as indicated in Table 1. All treatments were tested in three replicates. Emission sampling in all field trials was carried out using dynamic flux chambers by trapping the fumigants on either charcoal (for 1,3-D only) or XAD (for both 1,3-D and CP) sampling tubes. Some information about these chambers was provided in Gao et al. (2008) The samples were extracted and analyzed for the fumigants following similar procedures reported earlier (e.g., Gao et al., 2009). Both emission flux and cumulative emission loss were computed. In addition, fumigant concentrations in the soil-gas phase, residual fumigant in soil, soil water content and soil temperature were measured either during or at the end of the field trial. RESULTS: Data for cumulative emission loss are given in Table 1. Flux data (not given) usually correspond to cumulative emission loss with the exception that post-fumigation water treatment can affect flux dramatically. The results can be summarized as below: 1) Surface treatments are necessary for effectively minimizing fumigant emissions. Bare soils always gave the highest emission flux and cumulative emission loss for both broadcast shank
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