Effect of Furadan and Endotaf on Nitrogen Fixation Efficiency of Soil Alga Calothrix javanica de Wilde

摘要

In the present research endeavor, the effect of two commonly used pesticides Furadan (carbofuran, 3% G), and Endotaf (endosulfan, 35%) belonging to carbamate and organochlorine group, was studied on the nitrogen fixation efficiency of soil blue-green alga Calothrix javanica de Wilde. Total nitrogen fixed by the alga at each concentration of pesticides was estimated by conventional Micro-kjeldahl method in the laboratory cultures. The consequences of the results showed a progressive decline in the nitrogen fixation by the tested blue-green alga. Calothrix javanica with increasing concentrations of the pesticides. At higher dose level i.e., 500 ppm with Furadan and 100 ppm Endotaf, the tested alga showed 61.5% and 93.6% decrease in nitrogen content respectively over the control. However, the alga also showed increased nitrogen fixation at the lower doses of both the pesticides i.e., 2.5 ppm to 50 ppm furadan and 2.5 ppm to 5 ppm endotaf over the control. In the laboratory cultures among the studied pesticides, Endotaf was found to be more toxic than the Furadan to the tested alga. Calothrix javanica de Wilde. This suggest that indiscriminate use of Furadan and Endotaf pesticides may cause adverse effects on the nitrogen fixation of blue-green algae under various crop fields, which has a direct influence on total productivity.