Nav: Home

The discovery of a more effective method to estimate polluting emissions from nitrogen fertilizers

July 11, 2019

Agriculture contributes to 70% of total emissions by humans of nitrous oxide (N2O), a potent polluting gas and the one to blame for the hole in the ozone layer. The root of this issue is in the widespread use of chemical fertilizers, such as urea and ammonium nitrate. Once these products have been used in soil for crops, a portion of them are lost in the form of N2O, which goes directly into the atmosphere. The pollution problem of fertilizers is heightened with the growing rise in the demand for foods that require these fertilizers in order to attain profitable agricultural production.

The industry continues to search for formulas that reduce this pollution without negatively affecting production. Nevertheless, it is faced with a core problem. The emission of pollutants from fertilizers is very difficult to predict since it depends on factors that are hard to control, such as humidity, temperature, activity of microorganisms in the soil and variability of time and space, among others. If a realistic estimate of emissions from these pollutants cannot be made, it is tough to come up with strategies to reduce these emissions.

An international research group, including University of Cordoba researcher Antonio Rafael Sánchez Rodríguez, studied different mathematical prediction methods to measure the emissions of pollutants from fertilizers, such as urea and ammonium nitrate, in order to find out which one gives data that most closely resemble reality. This research is supported by the UK-China Virtual Joint Centre for Improved Nitrogen Agronomy (CINAg) and members from universities in the UK, Portugal, Australia and Spain have participated. Among those is British researcher Ute Skiba, who collaborates with the Intergovernmental Panel on Climate Change (IPCC) to reduce emission factors from pollutants used in agriculture.

In order to find a more efficient method, the research team tested and compared two statistical models. The first, known as the Bayesian method, is based on probability and provides results within a range of values that allows for inferring possible results. The second one, the trapezoidal method, is more widely used but is unable to predict variability of emission factors, since it estimates emission production to be linear, which is not actually the case. Emissions depend on many factors and changes in each one affect the reactions that are involved in emitting polluting gases.

The experiment took place on four experimental fields in the United Kingdom. Fertilizers were applied in the form of ammonium nitrate, urea and a third kind that was a mixture of urea and a potential inhibitor of urease, that minimizes ammonia emissions but, according to several studies, increases the emission of another pollutant, N2O.

The results show that N2O emissions were greater when ammonium nitrate was used, compared to using urea. Moreover, the use of the inhibitor did not show any significant differences in this sense. The research concludes that the Bayesian method offers more realistic predictions regarding nitrous oxide emissions, and therefore it is of great use when choosing more sustainable strategies for agriculture.

In its current condition, the Bayesian method is limited to cases in which fertilization produces a peak of emissions followed by a large drop. However, likewise, it is more useful than traditional methods when choosing a fertilization strategy that emits fewer polluting gases into the atmosphere. From now on, this research group will try applying this method in order to also measure emissions from organic nitrogen fertilizers.
-end-
N. Cowan, P. Levy, J. Drewer, A. Carswell, R. Shaw, I. Simmons, C. Bache, J. Marinheiro, J. Brichet, A.R. Sánchez Rodríguez, J. Cotton, P.W. Hill, D.R. Chadwick, D.L. Jones, T.H. Misselbrook, U. Skiba. "Application of Bayesian statistics to estimate nitrous oxide emisión factors of three nitrogen fertilisers on UK grasslands". Environment International. DOI: 10.1016/j.envint.2019.04.054

University of Córdoba

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".