Karim, M.F., Hao, P.,
Nordin, N.H.B., Qui, C.,
Zeeshan, M., Khan, A.A.,
Wu, F. and Shamsi, I.H.
2020
CO2 enrichment using
CRAM fermentation
improves growth,
physiological traits
and yield, of cherry tomato
(Solanum lycopersicum L.).
Saudi Journal of Biological
Sciences 27: 1041-1048.
NOTE:
Karim et al. (2020) say that
14.6% of 17.8 million hectares
of farmland in China is used
for indoor greenhouse farming.
The eight scientists
used composting
as a low-cost method
of increasing the CO2
concentration, within
farming greenhouses,
to boost crop yields.
SUMMARY:
A low-cost method
to raise the CO2
concentration
of a greenhouse
had a significant
positive impact
on cherry tomato
growth.
Plant height,
stem diameter,
leaf width and
chlorophyll content
increased by
37%, 17%, 14%
and 11.4%,
respectively,
relative to control
CO2 conditions.
Higher CO2 enhanced
net photosynthesis by +20%,
single fruit weight by +38%,
fruit diameter by +20%,
fruit number by +125%
and yield by +38%.
Higher levels of CO2
significantly increased
ascorbic acid
( vitamin C ),
and the content of
soluble sugars.
Karim et al. conclude
that their composting
method represents
"the most economical
and cost effective
[method to increase CO2]
for farmers
as compared to other
strategies such as
direct gas injection,
ventilation and chemical
production. ... and
"significantly improved
quality and increased
the yield of cherry tomatoes."
DETAILS:
They grew cherry tomato
(Solanum lycopersicum,
cv. Huangfei)
plants under control
( conventional cultivation )
and CO2-enriched
conditions, in two
large adjacent
greenhouses
in Huzhou, China.
Elevated CO2 conditions
were from constructing
five composting units
within one greenhouse,
with each unit consisting
of 25 kg of compost material
(wheat straw) and 8 kg
of moist manure.
Three fungal species
were supplied within the
compost mixture
to enhance the production
of CO2 via fermentation.
The resultant compost mixture
raised and maintained the CO2
between 1,000 and 1,500 ppm.
The control greenhouse ranged
between 480 and 570 ppm
during the cultivation period.
Karim et al. report that
elevated CO2 "triggered
an increase in peroxidase
and catalase antioxidant
enzymes,"
while also stimulating
malondialdehyde content,
which promoted the
development of "
an efficient antioxidant
defensive system for
reactive oxygen species."
