Asif, M.,
Zora, S.,
Ceylan, Y.,
Rehman, R. and
Ozturk, L.
2020
Nitrogen supply in combination
of nitrate and ammonium enhances
harnessing of elevated atmospheric
CO2 through improved nitrogen
and carbon metabolism in wheat
(Triticum aestivum)
Crop & Pasture Science 71: 101-112.
NOTE:
Multiple studies have reported
interactive effects of elevated CO2
and nitrogen (N) fertilizer rate
on wheat, yet few have investigated
as much for different N sources.
The researchers set out to
"investigate the effect of elevated CO2
on photosynthetic performance indicators,
biomass formation and carbon and
N metabolism in wheat plants
supplied with different N sources
(NH4+, NO3-, NH4+ plus NO3-, urea)."
SUMMARY:
The authors conclude that
"adequate and balanced nutrition
of C3 crops with NO3- and NH4+
[fertilization] is key to harnessing
[the yield-enhancing benefits
from] a future environment
with elevated CO2."
Protein and other micronutrient
declines that are sometimes
observed in crops at higher
CO2 concentrations can be
overcome by providing
the right balance of N supply.
The results
"suggest that N supply
in the form of NH4NO3 results in
higher shoot and root biomass
production under both ambient
and elevated CO2 conditions
by sustaining enhanced
photosynthesis and stable
allocation of biomass
and carbohydrates into s
hoots and roots compared
with sole application of NO3-,
NH4+ or urea."
Additionally,
"in contrast to the
general assumption
of a decrease in
total N concentration
at elevated CO2,
our results show
no decrease in
shoot or root
N concentration
at elevated CO2
except with urea
supply."
DETAILS:
Their experiment was
conducted hydroponically in a
controlled-environment setting,
where wheat (Triticum aestivum,
cv. Ceyhan-99) plants were grown
under either ambient (400 ppm)
or elevated (700 ppm) CO2
concentrations and supplied
with one of the four different
Nitrogen sources for 23 days.
CHART BELOW:
Biomass enhancement ratio
(ratio of biomass at elevated CO2
to that of ambient CO2) for shoot,
root and whole plant in 23-day-old
wheat plants grown in hydroponic
culture with four different sources
of nitrogen (NH4NO3, NO3-, NH4+
and urea).
