Why reducing nitrous oxide emissions is important?
Nitrous oxide is a gas that is produced by microbes present in the soil. Nitrous oxide (N2O) gas is one of the greenhouse gases that are responsible for trapping the heat in the atmosphere. According to the U.S. greenhouse gas emissions in 2019, nitrous oxide emissions account for 7% of the total greenhouse gases which, is comparatively smaller than other gases (United States Environmental Protection Agency n.d.). But the effect of the release of one molecule of nitrous oxide is equal to 300 times the effect of one molecule of carbon dioxide in the atmosphere (United States Environmental Protection Agency n.d.). One nitrous oxide molecule also stays in the atmosphere for about 114 years before getting disintegrated or removed by chemical processes(S. Solomon 2007).
Figure 1: Nitrous oxide Emissions(United States Environmental Protection Agency)
Causes of Nitrous oxide emissions
Approximately 40% of the nitrous oxide emission is man-made(Stocker 2013). The harmful gas Nitrous oxide emission is due to agricultural soil management, industry, wastewater treatment, and fuel combustion (United States Environmental Protection Agency n.d.). The majority of nitrous oxide emissions, according to the research done in U.S. come from agricultural soil management. The pesticides and fertilizers used for agriculture account for the major nitrous oxide emission. The domestic wastewater treatment corresponds to about 5% of the total nitrous oxide emission due to the nitrification and denitrification of nitrogen. The burning of fuel and the producing chemicals like nitric acid for fertilizers and adipic acid emits nitrous oxide. Adipic and nitric acid production accounts for 100 million metric tons emission of nitrous oxide.
How is nitrous oxide produced in agricultural soils?
Agriculture accounting for about 60% of the total nitrous oxide emission let’s understand how nitrous oxide gas is emitted in the atmosphere due to of agricultural practices.
The microbes release nitrous oxide during the nitrification and the denitrification process to spur nitrogen fertilization(Bouwman 2002.).
Nitrification: The process occurs when there are high ammonia levels in the soil and oxygen in the soil for the microbes to breathe; the ammonia is converted to nitrate. The nitrous oxide gas is produced when the nitrate conversion is not 100% efficient (Agriculture n.d.).
Denitrification: The denitrification process is a complementary step of nitrification, wherein the nitrate is converted into nitrogen. When nitrate is not fully converted to nitrogen, the nitrous oxide gas is emitted as an intermediate. The denitrification microbes breathe carbon that is produced by other microbes. The denitrification is bound in the presence of oxygen because oxygen destroys denitrifying enzymes (Agriculture n.d.).
Cons of Nitrous oxide emissions
The third most common greenhouse gas that is ignored largely is the nitrous oxide emissions. Nitrous oxide causes ozone layer to deplete. Nitrous oxide is the major culprit behind climatic changes. If nitrous oxide emission is reduced, air pollution, water pollution and biodiversity losses will substantially come down along with climatic changes.
Figure 2: An overview of nitrous oxide emission; Image Courtesy: (Tian 2020)
Research to Alleviate Climate Changes due to Nitrous Oxide emission
Reducing nitrogen fertilizers might be a good idea to mitigate nitrous oxide emissions. Also, the production of adipic and nitric acid must be reduced to reduce nitrous oxide emissions.
But, the research conducted by a team of researchers from Iowa State University indirectly tried to solve the problem of climate change due to nitrous oxide emissions. They showed that the warming of climate produced by nitrous oxide emissions is greater than the cooling by increasing carbon storage in the soil using traditional agricultural practices. Storing carbon in agricultural soils is a strategy to alleviate climate change. In addition to storing carbon, alleviate climate change. In addition to storing carbon, respective policies for reducing nitrous oxide emission also should be in place to mitigate the change in the climatic conditions. The research group headed by Hall also developed new technology by making some modifications to the existing technology to measure nitrous oxide emissions. The technology uses small containers on top of the soil of Iowa State University. The containers pump air, and an analyzer can measure nitrous oxide emissions. This technology can also withstand the moisture content in agricultural soils. This type of measurement of nitrous oxide has not been used elsewhere so far. (Nathaniel C. Lawrence 2021)
Few effective strategies to reduce nitrous oxide emission include precision agriculture, meaning precise use of nitrogen fertilizers. Ascend Performance Materials, a firm headquartered in the U.S., recently installed a new technology that combines selective catalytic reaction and thermal stability to reduce nitrous oxide emissions by half, was published recently in (ACS 2021).
It is all about the strategy to lessen the climatic changes that are triggered due to nitrous oxide emission. No one strategy can effectively mitigate climate change.
ACS, CEN. CEN ACS. June 2021. https://cen.acs.org/environment/climate-change/Nitrous-oxide-packs-dangerous-climate/99/i25.
Agriculture, Univery of California Sustainable. ucanr.edu. https://ucanr.edu/sites/
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Nathaniel C. Lawrence, Carlos G. Tenesaca, Andy VanLoocke, Steven J. Hall. “Nitrous oxide emissions from agricultural soils challenge climate sustainability in the US Corn Belt.” Proceedings of the National Academy of Sciences. 2021. 118 (46).
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