Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 20, 2009
Publication Date: February 3, 2009
Citation: Qin, R., S. Gao, H. Ajwa, B.D. Hanson, T.J. Trout, and D. Wang. 2009. Effects of organic amendment on degradation of 1,3-dichloropropene and chloropicrin in soil. p. 180. In Proceedings, 2009 California Plant and Soil Conference, Fresno, CA, February 3 & 4, 2009. Technical Abstract: Soil fumigants 1,3-dichloropropene (1,3-D) and chloropicrin (CP), are promising alternatives to the phased-out methyl bromide. However, these fumigants are volatile organic compounds and contribute to air pollution from emissions. Organic amendment to soils has been found to reduce emissions by increasing their adsorption or degradation, but conditions to maximize this effect has not been well defined. Laboratory incubation experiments were conducted to investigate important factors affecting the degradation of 1,3-D and CP in sandy loam soil under amendment with various composted organic materials at varying temperature (10, 30, and 45 ºC) and soil water content(air-dry to field capacity). Degradation of 1,3-D and CP over time followed pseudo first-order kinetics. The degradation of both 1,3-D isomers (cis-1,3-D and trans-1,3-D) was similar while the degradation of CP was generally faster than 1,3-D. Increased temperature accelerated fumigant degradation significantly, particularly for 1,3-D. Sterilization of the amended soils by autoclave did not reduce fumigant degradations indicating the accelerated degradation was by chemical reaction between organics and fumigants. The degradation of 1,3-D increased slightly with increased soil moisture, while the degradation of CP was not affected. Amendment with steer manure, chicken manure, organic composts, and grape pomace all accelerated fumigant degradation rate 2-3 times for 1,3-D compared to non-amended soil. The amendment effects on CP degradation was greater than 1,3-D. Fumigant degradation rates increased as the amount of steer manure increased and there was no interaction between soil moisture and the manure. These results suggest that soil moisture, temperature and organic amendments are important factors on the degradation of 1,3-D and CP and can be adjusted to achieve emission reduction under practical conditions.