Volume 16, Number 45: 6 November 2013
In a study recently published in Functional Plant Biology, Thilakarathne et al. (2013) describe the results of a study they conducted on seven different cultivars of spring wheat (Triticum aestivum), which they grew at either ambient CO2 (384 ppm) or elevated CO2 (700 ppm) in temperature-controlled glasshouses. What do you suppose they discovered the consequences of the elevated concentration of this nefarious EPA-declared air pollutant to be?
In the case of light-saturated net photosynthesis, they found an actual stimulation provided by the extra 316 ppm of CO2 that ranged from 31% for cultivar Drysdale to 75% for cultivar Yitpi. In the case of aboveground biomass production, they also found a CO2-induced stimulation. In this case, it ranged from 0% for the cultivar H45 to 133% for cultivar Gladius. And in the case of actual grain yield, the six scientists found a CO2-induced stimulation that ranged from 0% for cultivar H45 to 98% for cultivar Gladius, with the other five cultivars sprinkled somewhere in between.
Likewise, but many years earlier, Ziska et al. (1996) had grown well watered and fertilized plants of seventeen different cultivars of rice (Oryza sativa) from seed to maturity within glasshouses maintained at atmospheric CO2 concentrations of either 373 ppm (ambient) or 664 ppm (elevated), after which they had measured both total plant biomass and grain biomass. In their case, and when the plants had been grown within a normal air temperature range, a few cultivars exhibited no significant changes in response to the specific degree of atmospheric CO2 enrichment used in their study, while the most responsive cultivar - a tropical japonica type from Brazil - exhibited a whopping 265% increase in total plant biomass and an astounding 350% increase in grain biomass.
But to make what could become a long editorial short, we conclude that it would seem to be the way of wisdom to discover what cultivars of the crops you grow are most positively responsive to atmospheric CO2 enrichment under your particular growing conditions. Then, having made that determination, plant them ... and reap the significant and ever-increasing monetary benefits that can be extracted, right out of the air itself, as a consequence of the well-documented aerial fertilization effect of atmospheric CO2 enrichment, as well as the transpiration-reducing effect that typically accompanies it and reduces the amount of water that your crops would otherwise require. And if you do so, those "pennies from heaven" - both gained and saved - will add up rather quickly; and you'll be getting ever more of them with each passing year that the air's CO2 content continues to rise.
Do it now. And thereby teach your children to do it when it is their turn to take over the farm.
Sherwood, Keith and Craig Idso
References
Thilakarathne, C.L., Tausz-Posch, S., Cane, K., Norton, R.M. Tausz, M. and Seneweera, S. 2013. Intraspecific variation in growth and yield response to elevated CO2 in wheat depends on the differences of leaf mas per unit area. Functional Plant Biology 40: 185-194.
Ziska, L.H., Manalo, P.A. and Ordonez, R.A. 1996. Intraspecific variation in the response of rice (Oryza sativa L.) to increased CO2 and temperature: growth and yield response of 17 cultivars. Journal of Experimental Botany 47: 1353-1359.