Storms are usually accompanied by a hint of foreboding with their arrival. However, thunderstorms carry within them something that we fail to see–and it's not the difference between the blinding flash and thunderous sound. It is the heat that runs hotter than even the sun, breaking apart the nitrogen molecules present in the air, delivering the broken nitrogen to the soil and nourishing it.
The Thunderstorm’s Hidden Bounty
Atmospheric nitrogen exists in the form of N2 molecules, where the two atoms of nitrogen are bound by a triple covalent bond that is nearly indestructible, unless lightning is used. The atmosphere contains about 78% nitrogen, which in its existing form is unusable by living organisms. This bond cannot be broken by ordinary heat or pressure. However, a single lightning strike heats the air to around 30,000 degrees celcius, providing the extreme energy required to break one of the strongest bonds in chemistry.
The nitrogen atoms freed from their bonds are highly reactive and immediately combine once coming in contact with atmospheric oxygen, forming nitric oxide. After further interaction with the abundant oxygen present in the atmosphere, these molecules next form nitrogen dioxide. Nitric acid and nitrous acid are formed with the reaction of these compounds and atmospheric moisture. A process known as precipitation scavenging then takes place as the highly soluble nitric acid dissolves with the raindrops and effectively cleans all the reactive gases and delivers the nitrates formed to the soil through rain.
Ultimately, the nitrogen is then absorbed by the plants through their roots. Every second, approximately 40 to 50 of these lightning bolts strike the Earth’s surface. Approximately 5 to 8 million tons of nitrogen are fixed by lightning annually worldwide. This is equivalent to the weight of over half a million elephants. However, there is a large uncertainty in these estimates, as stated even by the scientists. Lightning therefore converts the very air we breathe to a liquid gold for the soil that the rain carries directly to the earth.
Significance of This Minor Source
Bacteria have been the major source of breaking down nitrogen and providing it to the plants; however, lightning, even as a minority, carries importance in this process. Lightning contributes just 2.4% of the 203 Tg N/yr of nitrogen fixed globally. However, since lightning breaks down nitrogen in the atmosphere, the usable nitrogen is available in places far and wide where bacteria can’t reach. This opens up the possibility of delivering nitrogen to ecosystems with limited nitrogen.
Nitrogen has a wider span that it covers through nitrates absorbed in rainwater. Every drop that falls on the land increases its fertility. Every thunderstrike brings with it fresh plant food, enriching the soil and supporting the growth of crops, forests and grasslands. Hence, providing aid at the base of the food web.
The first flush, as called by the researchers, is the first rain after a dry period. The effect of the lightning is the strongest when the rainfall with water containing nitrates hits the soil starved of moisture and nutrients. The first monsoon therefore doesn’t only help in watering the soil but also provides a natural fertiliser to it.
Inspiration throughout the Times
The natural fixation of nitrogen through lightning has been recognised even by scholars. It has become an inspiration for the industrial sector to produce similar energy to procure nitrogen for the growth of plants. The use of electricity to create nitrogen-derived fertilisers artificially first started in 1903. Soon after, the Haber-Bosch process was invented, which proved to be more cost-efficient and hence became the mainstay in a factory. The nitrogen fixation of this process reached 120 Tg N/yr by 2010, which is double the natural terrestrial nitrogen sources combined, 63 Tg N/yr.
The process uses high heat, high pressure and natural gas to fix nitrogen far more cheaply. However, this efficiency came with a cost greater than the cost reduction it provided. Haber-Bosch depends on fossil fuels, and much of the nitrogen it produces is washed away, contaminating rivers, groundwater and coastlines downstream. Estimates also suggest that less than a third is actually absorbed by soil.
Several attempts have been made to replicate lightning in the modern era due to this very drawback. Start-ups have especially been circling back to this phenomenon for inspiration. Debye Ltd., founded by a former space propulsion engineer, is a company based in the UK running an 18-month feasibility trial with the UK Agri-Tech Centre, where they’re testing a machine that fires electrical discharges into water similar to a lightning strike, to check what it does when it hits a pond or a wet field.
This trial is being run on lettuce crops in a vertical farming facility based in Stockbridge, funded by Innovate UK and the BBSRC. The aim is to switch to a small-scale farm within three years if the trial is successful. The final goal is to provide farmers with small, on-site units that turn already abundant natural resources air, water and electricity- into usable nitrogen fertiliser.
The science backing these efforts isn't just theoretical, either. In controlled lab experiments, researchers used electrical discharge, engineered to mimic lightning, on soil samples and measured the results directly. Just five minutes of treatment raised the soil's nitrogen content by roughly 200%, pushing it to levels many times higher than what a plant actually needs to thrive. It's a small-scale result, but it's concrete proof that the underlying chemistry works outside of a thunderstorm, not just inside one.
This technology is a boon to farmers, yet sometimes it is not the resource but mindset that causes changes to take place. Nitricity, a San Francisco-based company, was once the leading company in lightning-mimicking fertiliser technology. However, what they faced wasn’t a developmental issue, but the clients not adapting to the new technology, as seen in consumer surveys.
A Phenomenon Ways Before Development
Some researchers have found evidence that volcanic lightning, the eerie bolts that arc massive ash plumes during eruptions, also deposit nitrate left behind in the ancient volcanic rocks, providing hints that the same reaction may be involved in supplying some of the nitrogen-based rocks in the growth of the young, lifeless Earth. This age-old phenomenon has therefore been cultivating life before even the cultivation of civilisation began.
Lightning isn’t replacing the fertiliser bags, nor is it alone enough to feed the entire world. However, lightning has been present throughout the biosphere, tending to places where neither fertilisers nor bacteria could reach, giving birth to life. It is seen as one of the most frightening natural phenomena, yet it is also a life-giving force which we are currently trying to manufacture through artificial means.
Lightning isn’t a development; it is a discovery that was made centuries after it arrived in the atmosphere.
References:
- https://www.no-tillfarmer.com
- https://jaysciencetech.com
- https://thequran.love
- https://www.13newsnow.com
- https://www.sierraclub.org
- https://www.farminguk.com