Simulating emissions of 1,3-dichloropropene after soil fumigation under field conditions

Authors: Yates, Scott; Ashworth, Daniel

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2017
Publication Date: 12/1/2017
Citation: Yates, S.R., Ashworth, D.J. 2017. Simulating emissions of 1,3-dichloropropene after soil fumigation under field conditions. Science of the Total Environment. 621:444-452. https://doi.org/10.1016/j.scitotenv.2017.11.278.
DOI: https://doi.org/10.1016/j.scitotenv.2017.11.278

Interpretive Summary: Use of pesticides has led to increased crop production and a more abundant and varied food supply. However, emissions of pesticides to the atmosphere can adversely affect ecosystem and human health. Pesticide fate, transport and emissions are affected by many soil and environmental processes. Recent field and laboratory studies have produced information that can be used to test the predictive capability of fumigant emission models. This paper compares predicted and measured emissions of 1,3-dichloropropene in an effort to test model performance and to identify model weaknesses. As research improves our ability to predict fumigant emissions, methods can be developed to utilize these chemicals safely, leading to increased agricultural production while reducing adverse consequences on the environment and public health. This research should be useful for state and federal regulators conducting risk assessments of fumigant use as it provide information on the level of confidence in current model predictions.

Technical Abstract: Soil fumigation is an important agricultural practice used to produce many vegetable and fruit crops. However, fumigating soil can lead to atmospheric emissions which can increase risks to human and environmental health. The transport, fate and emissions of fumigants are affected by many soil and environmental processes and a complete understanding is needed to mitigate atmospheric emissions. Five large-scale field experiments were conducted to measure emission rates for 1,3-dichloropropene (1,3-D), a soil fumigant commonly used in California. Numerical simulations of these experiments were conducted in predictive mode (i.e., no calibration) to determine if simulation could be used as a substitute for field experimentation to obtain information needed by regulators. The results show that the magnitude of the volatilization rate and the total emissions could be adequately predicted for these experiments, with the exception of a scenario where the field was periodically irrigated after fumigation. The results show that the timing of the daily peak 1,3-D emissions was not accurately predicted for these experiments due to the peak emission rates occurring during the night or early-morning hours. This study revealed that more comprehensive mathematical models are needed to fully describe emissions of soil fumigants from field soils under typical agronomic conditions.