Lightning and Soil
Country: United States
Date: Summer 2010
Will soil struck by lightning produce better or faster
growing vegetation? Are there any growth benefits to soil that has
been struck by lightning?
I have not seen or heard any investigations about electrically processing
soil to make the soil more productive in growing plants. Neither have I
heard of lightning strikes improving the agricultural productivity of soil.
If that were true then vegetation around radio and TV antenna towers would
be extraordinary in size and amount.
Lightning strikes are such a local phenomenon, that I don't think that there
would be any investigations into this phenomenon because economic return
would be so improbable. Although there are ways of attracting lightning to
areas, to do that would involve placing vertical conductors into the soil
and then it would affect only such a small area that it is just impractical.
Artificial electrical processing like radiating the soil with
electro-magnetic waves would require portable generators that run on
gasoline or diesel fuel that would cut into profitability.
So the short answer to your question is no: soil struck by lightning will
not produce better or faster
growing vegetation. There are no growth benefits to soil that has been
struck by lightning.
The speed of a lightning strike is too short to produce any substantial
amount of say nitrogen oxides. In addition the strike also produces harmful
products, such as ozone and nitrogen dioxide. If that were not enough, the
energy can physically damage the plants. Think for a moment of what can
happen if lightning hits a tree. Yours is not a "silly" question; however,
lightning is just too out of control to be a beneficial source of fertilizer.
The soil itself tends to become fused into a glass where the electrical
current actually ran; that won't be very fertile.
On the other hand, the lightning stroke itself in the air will make some
of the nitrogen in the air combine with oxygen; the "fixed" nitrogen will
dissolve in falling rainwater and act as a fertilizer.
Richard E. Barrans Jr., Ph.D., M.Ed.
Department of Physics and Astronomy
University of Wyoming
There is no data that lightning directly enriches the soil it has struck.
While there are many forms of lightning, the ones that do strike the
ground will usually superheat the area. Beneficial effects, if any, would
come from heating, and since heating soil does not necessarily enrich it,
direct lightning strikes should have no growth benefits. In fact, sandy
soil may even become fused (forming silica glass called fulgurites) and may
planting less viable.
The idea that lightning might enrich the ground may have come from the
fact that when lightning causes forest fires, the ground after the fire
becomes suitable for planting. This is because the burning causes the
release of matter that essentially fertilizes the soil. Burning of old
growth also makes way for new growth which tends to appear to grow
vigorously compared to older vegetation. So the idea that lightning may
be beneficial for growth comes not from lightning itself but from the
burning and clearing of forests. Of course, the idea of burning down a
forest (or even grasslands) in order to allow for quick planting has been
shown to be good only for the first planting - since nutrients are
ultimately leached out of the soil so fast by such methods - that this
process of "slash and burn" is ultimately ecologically harmful anyway.
Greg (Roberto Gregorius)
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Update: June 2012