Denitrification in a Chinampa soil of Mexico City as affected by methylparathion

摘要

Chinampas are raised garden beds used for agriculture in the southeastern part of the Valley of Mexico since pre-Hispanic times, In modern times, large amounts of pesticides, such as methylparathion, have been used with an unknown effect on soil processes, such as denitrification and the ratio of N_2O-to-N_2. Soil from a Chinampa was amended with nitrate (NO_3) with or without chloramphenicol known to inhibit de novo synthesis of enzymes, with or without acetylene (C_2H_2) known to inhibit the reduction of nitrous oxide (N_2O) to dinitrogen (N_2) and spiked with or without methylparathion. Methylparathion increased the concentration of NO_2 and removal of NO_3 from soil, but increased the emission of N_2O and N_2. The concentration of NO_2 , the removal of NO_3 production, and the N_2O and N_2 emission rates were generally larger when the aerobic conditioning of the soil was less than 14 days. It was found that methylparathion increased the denitrification process and showed no inhibitory effects on emissions of N_2O or N_2.