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Saturday, November 9, 2019

Parvin et al. (2019) -- Elevated CO2 stimulated various faba bean growth and yield attributes, regardless of soil water conditions

Parvin, S., Uddin, S., 
Tausz-Posch, S., 
Fitzgerald, G., 
Armstrong, R. and 
Tausz, M. 

2019

Elevated CO2 
improves yield 
and N2 fixation 
but not grain 
N concentration 
of faba bean 
(Vicia faba L.) 
subjected to 
terminal drought. 

Environmental and 
Experimental Botany 165: 161-173.


NOTE:
Parvin et al. (2019) 
studied the response 
of faba bean 
(Vicia faba cv. Fiesta) 
to a +150 ppm 
CO2 enrichment 
under well-watered, and 
water-stressed conditions.


SUMMARY:
Rising atmospheric CO2 
greatly stimulated growth 
and yield of faba beans, 
especially in regions 
prone to water-stress. 

CO2-induced enhancements 
in plant water-use efficiencies 
mean the quality of faba bean 
harvest may also improve, 
especially in water-stressed 
regions.

The positive effects 
of elevated CO2 
were powerful enough 
to fully mitigate 
the growth retarding 
influences of drought, 
in terms of total 
plant biomass, 
seed yield, 
pod number, 
seed number 
and harvest index, 
resulting in levels 
not significantly 
different than plants 
in the control treatment, 
of well-watered conditions, 
and the ambient CO2 level.

As shown in the chart below:
 Under well-watered conditions 
elevated CO2 increased
faba bean pod number, 
seed number, 
total biomass, 
and seed yield by
+44%, +40%, 
+29% and +59%, 
respectively. 

Terminal drought
had a negative impact 
on plant growth and yield 
attributes, but under 
such water-stressed 
conditions,
elevated CO2 
still improved 
the pod number, 
seed number, 
total biomass, 
and seed yield by
+ 47%, +40%, 
+16% and +24%, 
respectively. 

The nitrogen (N) response
(content and concentration) 
of the faba bean plants 
across the different treatments:
   Elevated CO2 
increased total N content, 
under both well-watered, 
and water-stressed 
conditions, by 
+39% and +19%, 
respectively.



DETAILS:
Work was conducted at the 
Agriculture Victoria Research 
Plant Breeding Center in Horsham, 
Victoria, Australia in 2016. 

Using free-air CO2 enrichment 
(FACE) technology, six scientists
exposed faba bean crops 
to ambient (400 ppm) 
or elevated (550 ppm) 
CO2 levels under well-watered 
(soil maintained at 80% field capacity) 
until the reproductive phase. 

Then they induced 
terminal drought 
in half the crops 
in each CO2 treatment 
by withholding water 
until 30% field capacity 
was reached, maintaining
this level of water stress 
through harvest.