March 2021 - 22

PLANT & SOIL HEALTH
UF scientist finds way to reduce greenhouse gas in soil
By Brad Buck
University of Florida
When soil gets saturated with water,
the ground can produce nitrous oxide, a
greenhouse gas that depletes the ozone,
that layer that protects plants and animals
on Earth from harmful ultraviolet light.
For context, nitrous oxide is 310 times
more powerful than carbon dioxide,
another greenhouse gas that's harmful to
the ozone layer. That's why it's important
to minimize nitrous oxide emissions
from soils. Farms, lakes and rivers can
emit nitrous oxide because nitrate leaches
into water bodies from agriculture, said
University of Florida scientist David Liu.
Sudden, heavy rains can drench any
tropical or subtropical region. Florida's
deluges can waterlog plants and soils. This
can damage crops, especially vegetables,
because the soil lacks sufficient oxygen.
For example, a University of Florida,
Institute of Agricultural Sciences
(UF/IFAS) report showed losses of about
$77 million in the Florida vegetable
industry due to Hurricane Irene in 1999.
If an area gets flooded by rain or
someone irrigates too much, soil will run
out of oxygen, which damages plants and
soil microbes. That soil terrestrial life gets
ultraviolet light to reach the earth and
jeopardizes crops, livestock husbandry
and harms our health. "
For the study, published in the journal
Nature: Scientific Reports, Liu and his
colleagues put fertilizers with nitrogen
into containers of soil - both with and
without solid oxygen fertilizers. Then they
over-irrigated the soil in the containers,
sealed them and used syringes to collect
gas samples from the soil.
Then scientists found, calculated
No-till agricultural practices in vulnerable areas can significantly reduce soil erosion.
Photo: University of Illinois
oxygen from nitrate, which is converted
into a series of compounds - nitrous oxide
among them. But applying oxygen fertilizers
can minimize nitrous oxide emissions.
Liu, a UF/IFAS associate professor of
horticultural sciences, believes he has laid
the groundwork to lower nitrous oxide
in agricultural soils. In an experiment on
a research farm in Gainesville, Liu used
fertilizer and water to successfully lower
the chemical compound in the soil.
" Minimizing nitrous oxide emissions
is imperative to crop producers and those
who raise livestock, " Liu said. " Nitrous
oxide is the largest ozone-depleting
substance emitted through human
activities such as farming and is expected
to remain the largest throughout the 21st
century. The ozone layer helps protect and
shield plants, animals and people from
excessive ultraviolet light from the sun.
Damaging the ozone layer allows more
and compared the difference in nitrous
oxide emissions of the gas samples with
and without solid oxygen fertilizers.
When they applied fertilizer that
contained ammonium on the fields, the
fertilizer oxidized into nitrate within
two days, he said.
The scientific - and, eventually,
the practical - goal of Liu's research
is to lower nitrous oxide in fertilizers.
Applying oxygen fertilizers doesn't just
minimize nitrous oxide emissions, it also
helps flooded crops survive. For now, Liu
cautions that his research is not readily
applicable on a commercial scale.
" It can be useful across the globe, but
we have to do a lot more research before
we apply this method universally, " he
said. VGN
20 | VegetableGrowersNews.com
http://www.VegetableGrowersNews.com
March 2021

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