A study from the University of California, Riverside suggests that nitrogen released by gas-powered machinery can release carbon from dry soils and release it into the atmosphere, potentially contributing to climate change. increase.
Industrial production, agricultural practices, and vehicles burn fossil fuels that release nitrogen into the air. As a result, nitrogen levels in the Earth’s atmosphere have tripled since 1850. The research team set out to understand whether this extra nitrogen affects the soil’s ability to retain carbon and not become a greenhouse gas.
the corresponding paper of the study,Effects of Experimental Nitrogen Deposition on Soil Organic Carbon Storage in the Southern California Drylandswas published in a magazine global change biology.
The team uncovered some unexpected discoveries
“Since nitrogen is used as a fertilizer for plants, we expected that the additional nitrogen would promote plant growth and microbial activity, thereby increasing the carbon input to the soil,” said UCR’s Department of Environmental Science. Assistant professor and researcher.
This is unlike anything they’ve seen in the arid soils that cover most of Southern California. Instead, the team found that excess nitrogen acidifies dryland soils, leaching calcium under certain conditions.Calcium binds to carbon, and the two elements leave the ground together. .
How does nitrogen affect soil biological processes?
To obtain their results, the research team sampled soil from ecological reserves near San Diego and Irvine that were fertilized with nitrogen in long-term experiments. This allowed us to see exactly how much nitrogen was added and explain the observed effects.
Nitrogen often affects biological processes and affects how soil stores carbon. Methods include fueling plant growth and slowing down microbes that help break down dead things in the soil.
Researchers did not expect significant effects on carbon storage by abiotic or abiotic means.
The pH scale measures how acidic or alkaline something is. In general, soils resist drastic changes in pH by releasing elements such as calcium in exchange for acidity. Due to the presence of nitric acid soils at several sites in this study, the soils attempted to resist this acidity by releasing calcium. Some have been lost.
“This is a surprising result because the main effect appears to be abiotic,” commented Johann Püspök, a graduate student in environmental sciences at UCR and lead author of the study. “This means that the uncovered, bare soil plots with low microbial activity, which I always thought were areas of low microbial activity, now appear to be affected by nitrogen contamination. about it.”
Dryland soils are characterized by a limited ability to hold water and low levels of organic matter, and cover approximately 45% of the land area of the Earth. It is responsible for storing most of the world’s carbon.
We need to prepare for the future by reducing our carbon emissions
Future studies may shed more light on how dryland soils are affected by nitrogen pollution, as was the study plot. We need more information about how widespread it is and how it performs under non-experimental conditions of nitrogen deposition,” explained Püspök.
But with no quick fix to this phenomenon, and no clear way to reverse the process once it’s started, researchers are looking to reduce emissions as much as possible to help soils retain their carbon stocks. We recommend reducing it as much as possible.
Homyak concludes: It can also affect the amount of carbon these dryland systems can store for us.For many reasons we have to deal Air pollution”