Dong, J., Gruda, N.,
Li, X., Tang, Y., Zhang, P.
and Duan, Z.
2020.
Sustainable
vegetable production
under changing climate:
The impact of elevated CO2
on yield of vegetables and
the interactions with
environments-A review.
Journal of Cleaner Production
253: 119920.
NOTE:
Dong et al. (2020) say
"A comprehensive literature review
is urgently required to shed light
on the effects of elevated CO2
on yield and yield components
of vegetables" .
SUMMARY:
Rising CO2 stimulates
food crop productivities
and yields.
The grand mean for
all vegetable types
was a CO2-induced
increase of +34%
based on 8,877
observations.
Means of fruit, flower,
leafy, stem and
root vegetable types
were of similar
magnitude, increasing
by 30%, 40%, 38%, 46%
and 35%, respectively.
Elevated CO2 increased
the harvest index by 23%
and the root/shoot biomass
ratio by 8%.
The increase
in vegetable yield,
was mainly
associated with
a CO2-induced increase
in vegetable organ number
(32%) and mass (11%),
although fruit mass
increases (10%)
played a role as well.
DETAILS:
Using the
Web of Knowledge,
ScienceDirect and
Google Scholar
databases,
the six scientists
conducted a
comprehensive
literature search
for articles examining
the impacts of CO2
on vegetables.
The resultant search
identified 107 references
between the years
1964 and 2018.
The average ambient
CO2 concentration
was 350 ppm
( range between
200 and 500 ppm )
whereas the
enriched CO2
concentration
averaged 827 ppm
( range between
346 and 1200 ppm .
Dong et al. also
evaluated the response
of the vegetables
to elevated CO2 under
aboveground (ozone,
temperature and light)
or below ground
(water, salinity, nitrogen
availability and form)
growth-limiting
conditions.
They report that
"increments in vegetable yield
tended to be greater
[under environmental stresses]
compared to the lack of
environmental stresses,"
adding that
"elevated CO2 counteracts
some of the constraints
in yield increases
from elevated ozone
and heat stress,"
whereas it did not
improve yield under
drought stress
(compared to
well-watered
conditions).
CHART BELOW:
Effect of elevated CO2
on yield of different
vegetable types
( fruit, flower, leafy, stem
and root ) and all types
combined ( All Vegetables ).
Data are means
of percent change
(relative to ambient
CO2 conditions)
with 95% confidence
intervals (indicated
with error bars).
The total number
of observations
in each vegetable
category are
in parentheses.
