Effect of Straw Composting on the Degradation and Stabilization of Chlorophenols in Soil

Noncomposted and composted wheat straw have been compared with regard to their effects on the stabilization of 2,4-dichlorophenol and 4-chlororophenol residues in soil. Such molecules are potentially present in soils as they are formed through the aerobic degradation of phenoxyherbicides and other chlorinated pesticides. Using 14C ring labeled molecules, the transformations of these compounds have been followed during soil incubation experiments after their sorption on composted and non-composted straw. Straw composting changed the chemical and physical properties of the original material and modified some biological activity characteristics like the size of bacterial and fungal populations and the oxidative enzymatic activities. Straw composting decreased the mineralization of both chlorophenols and increased the formation of non-extractable or bound residues. This seems to be directly related to the activity of the microflora associated to composted straw.