Soil biochemical changes induced by three applied insecticides/nematicides | ||
| Journal of Pest Control and Environmental Sciences | ||
| Volume 7, Issue 1, April 1999, Pages 123-135 PDF (848.41 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jpces.1999.462098 | ||
| Author | ||
| Mohamed A. Radwan* | ||
| Department of Pesticides Chemistry. Faculty of Agriculture (El-Shatby). University of Alexandria, Egypt | ||
| Abstract | ||
| The effect of three granulated insecticides / nematicides, carbofuran, oxamyl and terbufos on the activities of three common soil enzymes (dehydrogenase, urease and catalase) and on soil respiration in clay loam soil was studied after prolonged time of applications under laboratory conditions. The relationships between the assayed enzymes and microbial respiration in treated and untreated soils were also investigated. The results indicated that carbofuran increased dehydrogenase activity at 15 and 50 days, while it decreased urease and catalase activities at 50 days from application compared with the control. Oxamyl treated soil, increased dehydrogenase and urease activities at 25 days and decreased the activities at 50 and 5 days, respectively. In case of catalase enzyme, oxamyl enhanced the activity at 7 days, but decreased its activity at the first day and at 35 days from application. Also, terbufos treatment appeared to cause an increase in dehydrogenase activity at 3, 25, and 50 days; urease at 25 days; and catalase at 7 days. Whereas the trend of increasing activity was reversed for urease at 7 and 50 days and for catalase at 35 days from application compared with control treatment. Respiration, as indicated by CO2-evolution form soil, showed significant differences was noticed with carbofuran or terbufos treatment over control treatment at 35 days. Oxamyl, on the other hand, has stimulatory effect in this respect at three level of times, 25, 35, and 50 days. Simple correlation analysis for the untreated soils, indicated that dehydrogenase activity was significantly (p<0.05) related to microbial respiration or to urease enzyme. As for the treated soils, only dehydrogenase activity showed a highly significant (p<0.01) negative correlation with urease activity in soil treated with carbofuran, oxamyl or terbufos. Besides, oxamyl treated soil, exhibited significant positive correlation between dehydrogenase and catalase enzyme activities. | ||
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