Does Lightning Help Grass Grow ?
More than a few homeowners know the widespread belief that a thunderstorm results in greener grass . That may or may not be exactly true , but what ’ s undeniable is that such a storm ’ s electrical display does contribute to plant nutrition and thus helps to some degree with the growth of grass . The connection might seem hard to grasp – what does a flash of lightning contribute to the health of turf ? – but it ’ s actually fairly straightforward , and an example of one of the planet ’ s fundamental , life-sustaining physical cycles .
Nitrogen Availability
Ethan Shaw
NEWS
Nitrogen is an essential nutrient for plants and other organisms , being a fundamental part of nucleic acids , amino acids and proteins , not to mention the photosynthesizing plant pigment called chlorophyll . It ’ s also the single most abundant gas in the Earth ’ s atmosphere , accounting for about 78 percent of its composition . ( Oxygen is the second-most abundant atmospheric gas , at about 20 percent .) Despite that abundance , atmospheric nitrogen ( N 2
) isn ’ t readily available to most lifeforms , basically because in this tightly bonded form it isn ’ t very reactive with other molecules . Only a relative few living things – certain kinds of bacteria , including the cyanobacteria loosely referred to as “ blue-green algae ” – can directly use it as is . Other organisms require nitrogen to be transformed , or “ fixed ,” into more reactive compounds such as nitrates ( NO 3
) or ammonia ( NH 3
) before they can use it for biological growth and processes .
Nitrogen Fixation and the Nitrogen Cycle
The process by which nitrogen is converted into a form usable to most organisms is called nitrogen fixation . The most significant pathway of nitrogen fixation is via the bacteria that can change the nitrogen molecule into nitrogen compounds such as ammonia . Some of these nitrogen-fixing microbes have symbiotic relationships with plant roots .
Atmospheric fixation is another way nitrogen gas can be transformed into nitrates and ammonia , and lightning is the means . Humans also artificially accomplish nitrogen fixation in the industrial production of fertilizers .
The conversion of nitrogen into biologically available compounds via fixation as well as other processes such as bacterial nitrification , and the release of nitrogen back into the soil and the atmosphere through organic decay and denitrification , create the nitrogen cycle , one of the core circuits defining the Earth ' s biosphere .
Lightning , aka Atmospheric Fixation of Nitrogen
The tremendous heat released by a bolt of lightning – some 50,000 degrees Fahrenheit , roughly five times the temperature of the sun ’ s surface – can split apart a nitrogen molecule to free up two nitrogen atoms . A liberated nitrogen atom can then bond with oxygen atoms to form nitrogen oxides that , dissolving into raindrops , become nitrates . The lightning-freed nitrogen may also bond with atmospheric hydrogen to form ammonia . These soluble nitrogen compounds then fall to the Earth in rainfall , providing natural , lightning-produced fertilizer for grass and other plants .
When you consider that some 40 lightning bolts flash over the ( mighty stormy ) Earth every second , you get a sense of the significance of this atmospheric nitrogen fixation , even if it ’ s overall less important than biological fixation . It ’ s been estimated that lightning produces roughly 13,000 tons of nitrates each day around the globe .
Lightning and Greener Grass ?
There ’ s no question that lightning provides a source of nitrogen useful for growing grass . As to whether the grass will actually turn greener directly on the heels of a thunderstorm – well , that ’ s a bit of a murkier connection .
Rainfall itself , whether associated with a cumulonimbus cloud or not , can result in a greener lawn given both the moisture it ’ s providing and the nitrates and ammonia ultimately produced by lightning – though not necessarily locally – which will contribute to greenhued chlorophyll production . Heavy downpours from a thunderstorm may also simply wash dust off grass leaves , resulting in a lusher , more vibrant appearance .
( Reviewed by Sylvie Tremblay , MSc . Molecular Biology and Genetics )
Grassroots Vol 21 No 4 December 2021 40