Influence of three carbamate pesticides on Mn and Fe status of saline sodic soil of Aligarh. Part-I

Chemistry Department, D. S. College, Aligarh-202 001, India

Manuscript received 25 July 2000, revised 3 December 2001. accepted 15 February 2002

The present study envisages the effect of different doses of three carbamate pesticides, namely, methyl NN'-dimethyl-N-(nethyl­carbamoyl)oxythiooxamimidate (Oxamyl) (I), S-ethyl-N-(methylcarbamoyl)oxythioacetamidate (II) and N-pheny1(1-ethylcar­bamoyl)propylcarbamatea (III) on the change in concentration of different forms of Mn and Fe status; change in pH, EC and redox potential (E_h) of a saline soil over a period of 90 days. The correlation coefficients amongst them are also calculated. The results reveal that there is an optimum effect on the water-soluble, exchangeable, active Mn; exchangeable and available Fe; EC and Eh, with 0.25 g kg^-1 soil of pesticide I; 0.2 g kg^-1 of pesticide II and 0.3 g kg^-1 soil of pesticide III after 30 days of application. The pH was found to decrease with the time upto 30 days. The water-soluble, exchangeable, active Mn; exchangeable, available Fe, El, and EC were positively correlated with each other, while negatively correlated with reducible Mn and pH. The results have been explained on the basis of chemical and microbial activity of pesticides in soils. The activity of carbamate pesticides is in the order, II > I > III.