Organic matter effects on phase partition of 1,3-dichloropropene in soil

The fumigant 1,3-dichloropropene (1,3-D), in combination with chloropicrin, is considered a major replacement to methyl bromide (MeBr). This study was conducted to better understand phase partitioning of 1,3-D and the role of organic matter in its adsorption to soil. Partition of 1,3-D between air and water (K-H), and between soil and water (K-f), was determined by quantifying the concentration in both phases upon equilibrium. At 20 degreesC, the K-H values of (2)- and (E)-1,3-D were 0.052 and 0.033, respectively. In four California and Florida soils, the K-f values of 1,3-D isomers ranged from 0.39 to 8.55, and the K-oc values ranged from 18 to 60. The relatively high K-H and low K-f imply that 1,3-D is highly mobile in most soils after subsurface application. Adsorption of 1,3-D in native soils and soils amended with manure compost increased with increasing soil organic matter content. This suggests that organic wastes may be applied to soil to increase 1,3-D adsorption, thus reducing its potential for off site movement.