The effect of nitrogenous fertilizers on methane oxidation in soil.

Abstract

One of the most prominent applications to increase agricultural yield is the application of nitrogenous fertilizers to the soil. The intermediate and final products of the mineralization/humidification that include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are released into the atmosphere while other final products are cycled into the soil upon completion of the related reactions that take place in soil. Released CO 2 , CH 4 , and N 2 O are the most notable factors responsible for global warming and are claimed to be remarkably serious when one accounts for all of the agricultural lands and other similar fields all around the globe. In the present study, the impact of NH 4 NO 3 with 26% N, which consisted of 19% NH 4 N (ammonium-N) and 7% NO3-N (nitrate-N), with and withouth nitrification inhibitor in the soil on CH4, CO2 and N2O gas emissions was monitored in a controlled laboratory environment as three parallel experiments. The amount of fertilizer applied to the soil layer was 90 kg N per hectare. The two treated soils and one control soil were incubated at 60% maximal water holding capacity at 25°C during the test period of 18 days to investigate, (a) nitrogenous fertilizer (NH 4 NO 3 ), (b) nitrogenous fertilizer plus nitrification inhibitor (NH4NO3 + N.I.), and finally (c) control for CH4, CO2, and N2O emissions. Gas compositions from the experimental soils were sampled at predetermined times in order to assess the CH4 release along with N2O and CO2 emissions. Analyses of the headspace on the 1st, 2nd, 4th, 7th, 10th, 14th and 18th days were completed in order to evaluate gas concentrations. The overall results indicate that NH4NO3 fertilization and NH4NO3 with a nitrification inhibitor application causes a statistically significant decrease in CH4 emissions and an increase in CO2 emissions into the atmosphere. N2O emissions were found to be statistically different with the NH 4 NO 3 application and control treatments. Yet, no significant change was observed in, the N2O concentrations with respect to time, based on the NH4NO3 with a nitrification inhibitor application compared to the control group.