Volume 9, Number 9: 1 March 2006
What will it take to feed five billion rice consumers in 2030? That is the question that plagues the mind of Gurdev S. Khush (2005) of the International Rice Research Institute in Metro Manila, Philippines. "According to various estimates," in his words, "we will have to produce 40% more rice by 2030 to satisfy the growing demand without affecting the resource base adversely," because, as he continues, "if we are not able to produce more rice from the existing land resources, land-hungry farmers will destroy forests and move into more fragile lands such as hillsides and wetlands with disastrous consequences for biodiversity and watersheds," echoing sentiments previously expressed by Wallace (2000), Tilman et al. (2001; 2002), Foley et al. (2005), and Green et al. (2005). Hence, as Khush puts it, the expected increase in the demand for food "will have to be met from less land, with less water, less labor and fewer chemicals."
How is it to be done?
Khush suggests a number of strategies for attacking the multifaceted problem, including conventional hybridization and selection procedures, ideotype breeding, hybrid breeding, wide hybridization and genetic engineering, all designed to increase the yield potential of rice. In addition, he emphasizes breeding for increased resistance to diseases and insect pests, as well as for enhanced abiotic stress tolerance, which is needed to withstand the negative impacts of drought, excess water, soil mineral deficiencies and toxicities, as well as unfavorable temperatures (both hot and cold).
We agree that all of these things are needed; however, as indicated by Tilman et al. (2001), "even the best available technologies, fully deployed, cannot prevent many of the forecasted problems." This was also the conclusion of Idso and Idso (2000), who acknowledged that "expected advances in agricultural technology and expertise will significantly increase the food production potential of many countries and regions," but who went on to note that these advances "will not increase production fast enough to meet the demands of the even faster-growing human population of the planet."
Fortunately, we have a strong ally in the ongoing rise in the air's CO2 concentration that may help us meet and surmount this daunting global challenge. Atmospheric CO2 enrichment, for example, has been demonstrated to significantly increase rice photosynthesis and biomass production (see our compilations of over 100 individual experimental results for photosynthesis and biomass responses of rice to CO2-enriched air in the Data section of our website). In addition, elevated CO2 concentrations have been shown to enhance the ability of rice to cope with both biotic and abiotic stresses (see Agriculture (Species - Rice) in our Subject Index). Hence, in addition to our purposeful directed efforts to increase rice yields in the years and decades to come, we will experience the unplanned help provided by the CO2 emissions that result from the burning of fossil fuels.
Working together, these two positive forces may help us meet the clear and present need to ramp up rice production to the degree required to adequately feed the world a mere quarter-century from now, and to do so without usurping all of the planet's available land and water resources and thereby consigning the bulk of "wild nature" to the ash heap of history. Without the help of both approaches, we will in all likelihood fail and, with the rest of the biosphere, suffer unimaginable negative consequences.
Sherwood, Keith and Craig Idso
References
Foley, J.A., DeFries, R., Asner, G.P., Barford, C., Bonan, G., Carpenter, S.R., Chapin, F.S., Coe, M.T., Daily, G.C., Gibbs, H.K., Helkowski, J.H., Holloway, T., Howard, E.A., Kucharik, C.J., Monfreda, C., Patz, J.A., Prentice, I.C., Ramankutty, N. and Snyder, P.K. 2005. Global consequences of land use. Science 309: 570-574.
Green, R.E., Cornell, S.J., Scharlemann, J.P.W. and Balmford, A. 2005. Farming and the fate of wild nature. Science 307: 550-555.
Idso, C.D. and Idso, K.E. 2000. Forecasting world food supplies: The impact of the rising atmospheric CO2 concentration. Technology 7S: 33-56.
Khush, G.S. 2005. What it will take to feed 5.0 billion rice consumers in 2030. Plant Molecular Biology 59: 1-6.
Tilman, D., Cassman, K.G., Matson, P.A., Naylor, R. and Polasky, S. 2002. Agricultural sustainability and intensive production practices. Nature 418: 671-677.
Tilman, D., Fargione, J., Wolff, B., D'Antonio, C., Dobson, A., Howarth, R., Schindler, D., Schlesinger, W.H., Simberloff, D. and Swackhamer, D. 2001. Forecasting agriculturally driven global environmental change. Science 292: 281-284.
Wallace, J.S. 2000. Increasing agricultural water use efficiency to meet future food production. Agriculture, Ecosystems & Environment 82: 105-119.