Nitrous oxide emissions from agricultural farms and its contribution to global warming

Abstract

Global warming is a universal issue caused by increasing atmospheric greenhouse gases such as nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). N2O is produced from natural and anthropogenic sources. Microbial processes of nitrification and denitrification produce N2O which is then released into the atmosphere. This research aims to estimate the emission rate of N2O through denitrification processes in a mechanized sugarcane farm in Metahara, Ethiopia. The LEACHN/LEACHM model was used to estimate the rate of denitrification and emission of N2O. The model was calibrated by groundwater nitrate concentrations estimated from laboratory measurements using the APHA 4500-NO3-B, Ultraviolet Spectrophotometric screening method. The results show that the amount of atmospheric nitrogen (N2O and N2) produced due to denitrification processes in the farm was 230.4 kg/ha/year. The share of N2O from this estimate was 1/41th, as the soil in the farm was alkaline (pH = 9.0). As a result, the annual N2O emission from the farm was estimated to be 5.62 kg/ha/year. This implies that the current farm management and nutrient and water application scenario in the area is causing a significant amount of N2O emissions to the atmosphere, which in turn has a collective impact on global warming.