Impact of certain pesticides on urease and dehydrogenase enzymes in soil during the cotton bollworms control [electronic resource]

Includes references.

The present study was carried out on 100 cultivated with cotton variety Giza 70 during the season of 2011 to determine the side effects of certain pesticides i.e.; chlorpyrifos, profenofos, cypermethria and alpba- cypermethrin which were used against the cotton bollworms on soil enzymes of urease and dehydrogenase. Three sprays for each insecticide were done and the spraying is carried two weeks after the previous spray. The average of urease activity for the three sprays were expressed as unconverted urea to NH4-N (%).Tbe results showed high enzyme activity in all treatments, while, the mean enzyme activity was signifieantly decreased after treatment with profenofos. For the average of enzyme dehydrogenase activity for the three sprays that expressed part per million (ppm) Formazan were determined. The results showed higher enzyme activity after application with chlorpyrifos, while, the activity was significantly decreased after application with Cypermthrin and profenofos, but, alpba- cypermethrin had mild effect on the enzyme.

Summary in Arabic.

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