Effect of methyl parathion on nitrous oxide production: A laboratory study

We investigated the diversity of a denitrifying gene (nirK) and the emission of CO2 and N2O, in a “chinampa” soil contaminated with methyl parathion. Soil at 40% of water holding capacity was spiked with methyl parathion at four concentrations (i.e. 0, 0.7, 1.47 and 4.27 g kg−1 dry soil), while emission of N2O and CO2 and nirK diversity was determined after 0, 1, 14, 30, 60 and 90 days. The emission of N2O on a daily base and the cumulative emission of CO2 was not affected by the different concentrations of methyl parathion applied to soil. The diversity of the nirK gene, determined by using temperature gradient gel electrophoresis (TGGE), decreased with increased methyl parathion application. It was found that methyl parathion had effect on the emissions of N2O and CO2, and reduced the diversity of the nirK gene. Consequently, the reduced diversity of the nirK gene could affect the emission of N2O.