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Atmospheric CO2 Enrichment Effects on Agricultural Plant Roots are Providing the Foundation for a New-and-Improved "Green Revolution"
Volume 14, Number 3: 19 January 2011

In a recent review article, Herder et al. (2010) write that humanity "is facing the major challenge of providing food security for an ever growing world population," citing the work of Godfray et al. (2010), while further noting that the planet's agricultural area is shrinking, due, in their words, "to erosion of hill-sides, soil degradation, landslides and the increasing demand for biofuels." What is more, they indicate that the magnitude of the problem is such that currently applied technology and available crop plants "will not be sufficient to feed the rapidly growing world population." So how did this sad state of affairs come to be? ... and what can be done to meet the challenges it presents?

The four researchers say that "in the past, improvement of crops and agricultural techniques has mainly focused on increasing shoot biomass and seed yield," but that "the relevance of the root system for food production has often been overlooked." This myopic view was unfortunate, for many aspects of root system development are essential for enabling optimal plant growth in the face of numerous belowground environmental stresses, such as drought, salinity and soil-borne pathogenic attacks; and they state that achieving improvements in this "hidden half" of a crop's environment represents "an underestimated and not fully exploited area for strategies to enhance yield."

So are today's research institutions up to the task of bringing about the needed improvements in our current crop plants? Not as well as they should be, apparently, or else there would be no need for Herder et al.'s call to improve agricultural plant root systems. Mankind in general, on the other hand -- albeit unknowingly -- has been hard at work on the task, and doing quite well we might add, all as a result of our burning of fossil fuels, which raises the atmosphere's CO2 concentration and improves plant root development and functions in a number of important and needful ways.

In Herder et al.'s analysis, for example, they indicate that crop plants of the future will need "an increased and more efficient root system" that includes "more lateral branches and/or higher number of root hairs," in order to "take up water and nutrients, to fix fertile soil and to prevent soil degradation." Happily, these are things that enriching the air with CO2 helps to bring about. They also note that "80% of land plants obtain important mineral nutrition through the ancient arbuscular endomycorrhizal symbiosis with Glomeromycota fungi species," which, according to Parniske (2008), are ubiquitous in soils. And this, too, is something that elevated CO2 helps to promote. In addition, they note the need for sufficient nitrogen availability to plants, which is provided to legumes by nitrogen-fixing soil bacteria located within nodules on their roots; and this need is also met by increasing atmospheric CO2 concentrations.

All of these claims may be readily verified by perusing the many synopses of peer-reviewed scientific journal articles we have archived in our Subject Index under the headings of Soil (Erosion), Water Stress (Agricultural Crops), Pathogens, Fungi (Herbaceous Plants), Nitrogen Fixation (Herbaceous Plants), Growth Response to CO2 with Other Variables (Disease) and Roots. Check them out for yourselves, and see why we regularly refer to carbon dioxide as the elixir of life.

Sherwood, Keith and Craig Idso

Godfray, H.C.J., Beddington, J.R., Crute, I.R., Haddad, L., Lawrence, D., Muir, J.F., Pretty, J., Robinson, S., Thomas, S.M. and Toulmin, C. 2010. Food security: The challenge of feeding 9 billion people. Science 327: 812-818.

Herder, G.D., Van Isterdael, G., Beeckman, T. and De Smet, I. 2010. The roots of a new green revolution. Trends in Plant Science 15: 600-607.

Parniske, M. 2008. Arbuscular mycorrhiza: the mother of plant root endosymbioses. Nature Reviews Microbiology 6: 763-775.