|Knuteson, J. - FLUX EXPERTS|
|Ernst, Fred - UC RIVERSIDE|
|Zheng, Wei - UC RIVERSIDE|
|Wang, Q - DELAWARE STATE UNIV|
Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 18, 2008
Publication Date: January 12, 2008
Citation: Yates, S.R., Knuteson, J., Ernst, F.F., Zheng, W., Wang, Q. 2008. Effect of Sequential Surface Irrigations on Field-Scale Emissions of 1,3-Dichloropropene. Environmental Science and Technology. 42(23):8753-8758. Interpretive Summary: A field experiment was conducted to determine if repeated surface water seals (i.e., irrigations) would lead to reduced 1,3-D emissions to the atmosphere compared to traditional fumigation practices. The field experiment was conducted during early September of 2005 and measured the volatilization of Telone (1,3-dichloropropene, 1,3-D) after shank application at a depth of 45 cm. The field received 5 irrigations of approximately 1.25 cm of water immediately after fumigation and at 11 am the following four days. Several methods were used to measure the volatilization rate, including the aerodynamic, integrated horizontal flux, and theoretical profile shape methods. The results from the field study indicate that use of irrigation water to seal the soil surface layer is an effective method to reduce emissions. Total emissions of 1,3-D were found to be from 10-17% of the applied chemical. Several studies conducted by other researchers have shown that 1,3-D volatilization after shank injection exceeds 25 % of the applied chemical, and may be as high as 30-40%. A laboratory study that used the same soil and replicated the observed temperature conditions at the field site, found that emissions of 1,3-D would be approximately 30-35% when the soil surface remains dry. When the laboratory column was irrigated in the same manner as the field site, the emissions were approximately 15%. This study is unique in that the effect of a surface water seal on emissions of 1,3-D has been quantified. These results are also useful in providing a simple, cost-effective, method to reduce volatile organic carbon (VOC) emissions to the atmosphere. This will help growers to meet future regulations on VOC emissions as a result of EPA’s ambient air quality ozone standards.
Technical Abstract: A field experiment was conducted to measure subsurface movement and volatilization of 1,3-dichloropropene (1,3-D) after shank injection to an agricultural soil. The goal of this study was to evaluate the effect of sprinkler irrigation on the emissions of 1,3-D to the atmosphere and is based on recent research that has shown that saturating the soil pore space reduces gasphase diffusion and leads to reduced volatilization rates. Aerodynamic, integrated horizontal flux, and theoretical profile shape methods were used to estimate fumigant volatilization rates and total emission losses. These methods provide estimates of the volatilization rate based on measurements of wind speed,temperature, and 1,3-D concentration in the atmosphere. The volatilization rate was measured continuously for 16 days, and the daily peak volatilization rates for the three methods ranged from 18 to 60 µg m-2 s-1. The total 1,3-D mass entering the atmosphere was approximately 44-68 kg ha-1, or 10-15% of the applied active ingredient. This represents approximately 30-50% reduction in the total emission losses compared to conventional fumigant applications in field and fieldplot studies. Significant reduction in volatilization of 1,3-D was observed when five surface irrigations were applied to the field, one immediately after fumigation followed by daily irrigations.