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Thursday, May 30, 2019

Qiao et al. (2019) -- Elevated CO2 and Temperature Improve Soybean and Corn Quality and Yields


Qiao, Y., Miao, S., Li, Q., 
Jin, J., Luo, X. and Tang, C.

2019.

"Elevated CO2 and temperature 
increase grain oil concentration 
but their impacts on grain yield differ 
between soybean and maize grown 
in a temperate region." 

Science of the Total Environment 666: 
405-413.



SUMMARY:
Lots of good news here !

Elevated temperature 
and elevated CO2 together 
enhanced the quantity 
and quality of soybean 
and maize grain yields. 

Such findings are 
even more evidence
that a warmer planet, 
with more CO2 in the air, 
will increase food supplies.



DETAILS:
Qiao et al. (2019) 
investigated 
elevated temperature, 
with and without 
elevated CO2, 
on soybean 
(Glycine max, cv. Dongsheng 2) 
and maize (corn)
(Zea mays, cv. Demeiya 1) 
yield and grain quality. 

The six scientists grew 
the two crop species 
in three environmental 
treatments in open-top 
chambers located in 
Hailun County, 
Heilongjiang, China, 
across five growing 
seasons. 

The three treatments:
(1) ambient temperature 
and ambient CO2, 

(2) ambient CO2 and 
elevated temperature 
(2.1 °C above ambient), 

(3) elevated temperature 
(+1.5 °C above ambient) 
and elevated CO2 (700 ppm). 

Elevated CO2 concentrations 
were only during daylight hours
(0600-1800 hours).

Results are summarized 
below and in the charts.

Average grain yield of soybeans 
increased by +31% in the elevated 
temperature and elevated CO2 
(eTeCO2) treatment, compared to 
the control.

There was no significant difference 
between the control and elevated 
temperature (eT) only treatment
for soybeans.

For maize, average grain yields 
rose by +25% in both 
the eT and eTeCO2 treatments 
compared to control.

For grain oil concentration, 
which Qiao et al. say is 
"an important 
quality indicator", 
it was +9% higher
and +14% higher 
in soybeans, and 
+12% higher 
and +20% higher 
in maize in the 
eT and eTeCO2 
treatments, 
respectively.

Grain protein concentration 
in both crops were not 
statistically different among 
the three treatments for 
soybean or maize, but did 
increase (relative to control) 
by +3.3% in both eT and eTeCO2 
treatments for soybean, 
by +3.5% in the eT treatment 
for maize and by +4.6% in the 
eTeCO2 treatment for maize.

Qiao et al. also measured 
several nutrients in the grains. 

Phosphorus (P), potassium (K), 
calcium (Ca), iron (Fe), zinc (Zn) 
and manganese (Mn) tended to be 
somewhat enhanced in the 
eTeCO2 treatment. 

Relative to the ambient control, 
the percent change in P, K, Ca, Fe, 
Zn and Mn in the eTeCO2 treatment 
was +5%, +2.5%, +2.6%, +8%, +2% 
and -10% for soybean,  and
+2%, +4%, (-1%), +16%, 0%, 
and +8% for maize.