Author
OU, L-T - UNIVERSITY OF FL | |
THOMAS, J - UNIVERSITY OF FL | |
Allen Jr, Leon | |
Vu, Joseph | |
DICKSON, D - UNIVERSITY OF FL |
Submitted to: Archives of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/17/2006 Publication Date: 8/1/2007 Citation: Ou, L., Thomas, J.E., Allen Jr, L.H., Vu, J.C., Dickson, D.W. 2007. Effects of injestion systems and plastic mulches on distribution and emissions of Cis-and Trans-1,3-Dichloropropene and Chloropicrin. Archives of Environmental Contamination and Toxicology. 53:141-150. Interpretive Summary: Methyl bromide will be phased out since it has ozone depletion potential. Telone C35 [1,3-dichloropropene (1,3-D) plus chloropicrin (CP)] is an alternative soil fumigant. However, this fumigant has not been as effective as methyl bromide. Alternative delivery systems and virtually impermeable films (VIF) might improve dispersal and retention. Concentrations of 1,3-D and CP were determined in field beds after injection by chisels or an Avenger coulter. Beds were covered with either metallic polyethylene film (MPE) or VIF. Three hours after chisel injection, fumigant dispersal was highly variable but it was more uniform in the coulter injected beds. With time, concentrations in the top 30 cm layer became more uniform and then declined slowly. Volatilization was lower from VIF than MPE covered beds. The combination of coulter injection and VIF mulch provided better distribution and retention of fumigants and thus should provide better efficacy and crop yield. Nematode control in Telone C35 treatments was better than untreated beds and was similar to control in methyl bromide treatments. Tomato yields from Telone C35 treatments were generally greater than untreated beds, but less than methyl bromide injected beds. Technical Abstract: Alternative preplant delivery systems and plastic mulches might improve distribution and retention of fumigants. Concentrations of cis- and trans-1,3-dichloropropene and chloropicrin were determined at three cross-row locations in plastic covered field beds after injection of Telone C35 by conventional chisels or an “Avenger” coulter rig. Beds were covered with metallic polyethylene film (MPE) or virtually impermeable film (VIF). Three hours after chisel injection, fumigant concentrations were highly variable. Concentrations were more uniform yet variable in the Avenger coulter injected beds. With time, fumigant concentrations in the 0.5-30 cm soil layer became progressively more uniform and then declined slowly. Volatilization losses from VIF covered beds were lower than MPE. The combination of Avenger coulter injection and VIF provided better distribution and retention of the compounds and thus should provide better fumigant efficacy and crop yield. Nematode control (less tomato root galling) in Telone C35 treatments was better than untreated beds and was similar to control in methyl bromide treatments. Tomato yields from Telone C35 treatments were generally greater than untreated beds, but less than methyl bromide injected beds. |