|Qin, Ruijun - UC DAVIS|
|Tharayil, Nishanth - UC RIVERSIDE|
Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: September 9, 2008
Publication Date: November 11, 2008
Citation: Gao, S., R. Qin, N. Tharayil, B. Hanson, J. Gerik, D. Wang, and T. Trout. Emissions of 1,3-dichloropropene and chloropicrin from soils with manure amendment and post-fumigation water treatment. Ann. Int. Res. Conf. on MeBr Alternatives and Emission Reductions, San Diego, Nov. 11-15, 2008. pp. 34-1 to 34-2. Interpretive Summary: Achieving low emissions from soil fumigation will allow growers to use fumigants to minimize environmental pollution and thereby meet air quality standards. Methods that are effective to reduce emissions, economically feasible and environmentally sound are mostly desired. The objective of this study was to determine the effectiveness of soil amendment with composted manure with or without water applications on emission reductions. A field trial was conducted in a sandy loam soil in the San Joaquin Valley of California in fall 2007. Field treatments included manure application rates at 12.4 and 24.7 Mg/ha, manure application at 12.4 Mg/ha plus either HDPE tarp or post-fumigation water seals. Emissions of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) were monitored from shank injection of Telone C35. Results showed that both manure application rates alone did not reduce emissions compared to the control (no surface treatment). However, water treatments with or without manure application significantly reduced emissions, and the effect was greater on peak emission (80% reduction) than 10-day cumulative emission loss (~50%). Placement of HDPE tarp over manure amended soil resulted in the lowest CP emissions, but slightly higher 1,3-D emissions than the water treatments. This research provided the information that is for growers or different commodities and regulatory agencies to identify agricultural practices to minimize emissions from soil fumigation.
Technical Abstract: Minimizing fumigant emissions following field applications is required for achieving air quality standards. Application of organic materials (OM) to soil has been effective in reducing fumigant emissions during laboratory tests; but the potential to reduce emissions has not been evaluated considering field practices (e.g., incorporation methods, application rates and interaction with other manageable factors). The objective of this study was to determine the effectiveness of soil amendment with composted manure and evaluate its interaction with surface treatments on emission reductions in a field trial. The treatments included manure incorporated to the surface soil at 0 (control), 12.4 and 24.7 Mg ha-1, manure (12.4 Mg ha-1) plus either high density polyethylene (HDPE) tarp or water seals (irrigated 13 mm water immediately after fumigant injection, and 4 mm at 12, 24, and 48 h), and the water seals without manure incorporation. Telone C35 was shank-applied at 553 kg ha-1. Emissions of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) were monitored for 10 days. The data indicate that the manure application alone did not reduce emissions compared to the control. In contrast, the water treatments with or without OM application significantly reduced emissions, although the effect was greater on peak emission (80% reduction) than cumulative emission loss (~50%). The Manure+HDPE treatment resulted in the lowest CP emissions but slightly higher 1,3-D emissions than the water treatments. The significant peak emission reduction from water treatment is important in reducing acute exposure risk to workers and bystanders. This research indicated that OM amendment alone could not adequately reduce fumigant emissions under field conditions.