Volatilization of 1,3-dichloropropene under different application methods

Atmospheric emission of volatile pesticides can be a significant source of air pollution. A field study was conducted to reduce 1,3-dichloropropene (1 ,3-D) emission by applying the chemical via subsurface drip irrigation with a reduced dosage (4.7 g m(-2) or 47 kg ha(-1)). Comparisons were made betw een a shallow drip application with the plot covered with a polyethylene fi lm, a deep drip application and a conventional shank injection (at 11.2 g m (-2)) with the plots left as bare soil surface. For each treatment, seven r eplicated active flux chambers were used continuously to measure 1,3-D loss until no measurable emission was found. Results indicated that total 1,3-D emission loss was over 90% for the shank injection, and 66 and 57% for the shallow and deep drip plots, respectively. The emission loss was extremely high for shank injection since about 80% were lost from the bed furrows wh ere the slanted shanks left uncompacted fractures. On mass basis, the shank plot lost 10.4 g m(-2), whereas the shallow- and deep-drip plots lost 3.1 and 2.7 g m(-2), respectively. Applying 1,3-D using subsurface drip irrigat ion with reduced dosage has a great potential for emission reduction.