Environmental studies on ametryne herbicide. photodegradation, dehydrogenase activity, and phosphorus mineralization in treated soil

Photodegradation of Ametryne was evaluated by determining the residues after photolysis using gas-liquid chromatography. The residue of this compound was degraded as dry film by 62.5% of the tested amount within 18 hrs. of exposure to sun light. The percent degradation achieved after 45 hrs. of exposure on soil surface was 67. Ametyyne treatments stimulated dehydrogenase activity in clay loam soil. The technical grade gave the highest stimulation, however, the dehydrogenase activity as formazan contents were 157.7, 104.4 and 52.0 ppm with Ametryne technical grade, Ametryne WP formulation and untreated control treatments, respectively. The effect on phosphorus mineralization during the study showed that Ametryne technical grade was more effective than WP formulation as an inhibitor to this biological process. The mean effect at the end of experiment indicated that ametrine technical grade had a depressing effect while its WP formulation had no effect. the available Pi was 48.95, 54.42, and 56.62 ppm for technical grade WP formulation and control respectively.