Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 21, 2009
Publication Date: September 1, 2009
Citation: Qin., R., S. Gao, H. Ajwa, B. D. Hanson, T.J. Trout, D. Wang, and M. Guo. Interactive effect of organic amendment and environmental factors on degradation of 1,3-dichloropropene and chloropicrin in soil. J. Agric. Food Chem.57:9063-9070.2009 Interpretive Summary: Organic amendments to surface soils were found to reduce fumigant emissions because organic material (OM) can accelerate fumigant degradation and increase their adsorption in soil. To effectively apply this technique, better understanding on the role of OM in fumigant degradation under varied environmental conditions is needs. In this incubation study, we determined the degradation rates of cis- and trans-1,3-dichloropropene (1,3-D) and chloropicrin in soils with/without OM amendment under a range of soil moisture, temperature, sterilization, and soil texture conditions. Our results showed that amendment with several OM materials accelerated the degradation of both 1,3-D and CP greatly. OM amendment rate and soil temperature are the most important factors affecting fumigant degradation. This information is helpful for developing effective OM amendment strategies in the field to reduce fumigant emission.
Technical Abstract: Soil organic matter is an important factor affecting the fate of fumigants and organic amendment of surface soils could reduce fumigant emissions by accelerating fumigant degradation and increasing adsorption. Experiments were conducted to determine the degradation rate of cis- and trans-1,3-dichloropropene (1,3-D) and chloropicrin (CP) in soils with organic amendment under a range of soil moisture, temperature, sterilization, and soil texture conditions. Degradation of the fumigants followed availability-adjusted first-order or pseudo first-order kinetics with slower degradation of 1,3-D than CP. Increasing soil water content from 5% to 17.5% (w/w) slightly increased the degradation of 1,3-D, but not CP. All five organic amendments at 5% (w/w) increased fumigant degradation 1.4-6.3 fold. The degradation of both fumigants was accelerated with increasing amount of organic material (OM). Little interaction between soil moisture and OM was observed. Autoclaved soils did not reduce degradation of either fumigant. Increased temperature from 10 to 45 ºC accelerated fumigant degradation 5-14 times. Soil texture did not affect 1,3-D degradation but CP degraded faster in finer-textured soil. These results suggest that OM type and rate and soil temperature are the most important factors affecting degradation of 1,3-D and CP.