Emission of methane and nitrous oxide from Vigna mungo and Vigna radiata legumes in India during the dry cropping seasons

Abstract

Methane (CH4) and nitrous oxide(N2O)emission estimates were made for Vigna mango and Vigna radiata legumes. The affecting soil parameters like redox potential, soil temperature were studied to evaluate CH4 and N2O emissions. The CH4 was negative and N2O was positive for Vigna mungo, almost throughout the cropping period. The redox potential was more than +100 mV during the entire cropping period with a maximum N2O flux of 11.67 mu g m(-2) h(-1). The raise in soil temperature and the redox potential during harvest further increased the N2O flux to 18.38 mu g m(-2) h(-1). The seasonally integrated flux E((SIF)) for CH4 and N2O for Vigna mungo was calculated to be -4.06 g.m(-2) and 3.38 mg m(-2) respectively. Similarly E((SIF))values estimated for Vigna radiata cropping season were 0.009 g m(-2) and -7.6 mg m-2, whereas for the post harvesting period the fluxes were 0.02 g m(-2) and 4.06 mg m(-2) for CH4 and N2O respectively. The soil parameters like organic carbon and nutrients such as ammonia, nitrate and nitrite during the cropping season were evaluated. The emission of greenhouse gases (GHG) was also correlated to various physicochemical parameters of soil.