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Chapter 9. Feeding Eight Billion Well: Rethinking Land Productivity
The shrinking backlog of unused agricultural technology and the associated loss of momentum in raising cropland productivity is found worldwide. Between 1950 and 1990, world grain yield per hectare climbed by 2.1 percent a year, ensuring rapid growth in the world grain harvest. From 1990 to 2007, however, it rose only 1.2 percent annually. This is partly because the yield response to the additional application of fertilizer is diminishing and partly because irrigation water supplies are limited. 7
This calls for fresh thinking on how to raise cropland productivity. One way is to breed crops that are more tolerant of drought and cold. U.S. corn breeders have developed corn varieties that are more drought-tolerant, enabling corn production to move westward into Kansas, Nebraska, and South Dakota. Kansas, the leading U.S. wheat-producing state, has used a combination of drought-resistant varieties in some areas and irrigation in others to expand corn planting to where the state now produces more corn than wheat. Similarly, corn production is expanding in more northern states such as North Dakota and Minnesota. 8
Another way of raising land productivity, where soil moisture permits, is to increase the area of multicropped land that produces more than one crop per year. Indeed, the tripling in the world grain harvest since 1950 is due in part to impressive increases in multiple cropping in Asia. Some of the more common combinations are wheat and corn in northern China, wheat and rice in northern India, and the double or triple cropping of rice in southern China, southern India, and rice-growing countries in Southeast Asia. 9
The spread in double cropping of winter wheat and corn on the North China Plain helped boost China’s grain production to where it rivaled that of the United States. Winter wheat grown there yields close to 4 tons per hectare. Corn averages 5 tons. Together these two crops, grown in rotation, can yield 9 tons per hectare per year. China’s double cropped rice yields 8 tons per hectare. 10
Forty years ago, North India produced only wheat, but with the advent of the earlier maturing high-yielding wheats and rices, wheat could be harvested in time to plant rice. This wheat/rice combination is now widely used throughout the Punjab, Haryana, and parts of Uttar Pradesh. The wheat yield of 3 tons and rice yield of 2 tons combine for 5 tons of grain per hectare, helping to feed India’s 1.2 billion people. 11
In North America and Western Europe, which in the past have restricted cropped area to control surpluses, there is some potential for double cropping that has not been fully exploited. In the United States, the lifting of planting area restrictions in 1996 opened new opportunities for multiple cropping. The most common U.S. double cropping combination is winter wheat with soybeans as a summer crop. Since soybeans fix nitrogen, this reduces the need to apply fertilizer to wheat. 12
A concerted U.S. effort to both breed earlier maturing varieties and develop cultural practices that would facilitate multiple cropping could substantially boost crop output. If China’s farmers can extensively double crop wheat and corn, then U.S. farmers—at a similar latitude and with similar climate patterns—could do the same if agricultural research and farm policy were reoriented to support it.
Western Europe , with its mild winters and high-yielding winter wheat, might also be able to double crop more with a summer grain, such as corn, or with a winter oilseed crop. Elsewhere, Brazil and Argentina have an extended frost-free growing season that supports extensive multicropping, often wheat or corn with soybeans. 13
In many countries, including the United States, most of those in Western Europe, and Japan, fertilizer use has reached a level where using more has little effect on crop yields. There are still some places, however, such as most of Africa, where additional fertilizer would help boost yields. Unfortunately, sub-Saharan Africa lacks the infrastructure to transport fertilizer economically to the villages where it is needed. As a result of nutrient depletion, grain yields in much of sub-Saharan Africa are stagnating. 14
One encouraging response to this situation in Africa is the simultaneous planting of grain and leguminous trees. At first the trees grow slowly, permitting the grain crop to mature and be harvested; then the saplings grow quickly to several feet in height, dropping leaves that provide nitrogen and organic matter, both sorely needed in African soils. The wood is then cut and used for fuel. This simple, locally adapted technology, developed by scientists at the International Centre for Research in Agroforestry in Nairobi, has enabled farmers to double their grain yields within a matter of years as soil fertility builds. 15
Another often overlooked issue is the effect of land tenure on productivity. In China, this issue was addressed in March 2007 when the National People’s Congress passed legislation protecting property rights. Farmers who had previously occupied their land under 30-year leases would gain additional protection from land confiscation by local officials who, over a number of years, had seized land from some 40 million farmers, often for development. Secure land ownership encourages farmers to invest in and improve their land. A Rural Development Institute survey in China revealed that farmers with documentation of land rights were twice as likely to make long-term investments in their land, such as adding greenhouses, orchards, or fishponds. 16
Despite local advances, the overall loss of momentum in expanding food production is unmistakable. It will force us to think more seriously about stabilizing population, moving down the food chain, and using the existing harvest more productively. Achieving an acceptable worldwide balance between food and people may now depend on stabilizing population as soon as possible, reducing the unhealthily high consumption of animal products among the affluent, and restricting the conversion of food crops to automotive fuels.
7. Ibid.; Worldwatch Institute, op. cit. note 4.
8. USDA, National Agricultural Statistics Service (NASS), Crop Production 2006 Summary (Washington, DC: January 2007); USDA, NASS, QuickStats, electronic database, at www.nass.usda.gov/Data _and_Statistics/Quick_Stats, viewed 28 September 2007.
9. USDA, op. cit. note 1; Worldwatch Institute, op. cit. note 4.
10. John Wade, Adam Branson, and Xiang Qing, China Grain and Feed Annual Report 2002 (Beijing: USDA, 2002); USDA, op. cit. note 1.
11. Double-cropping yields from USDA, India Grain and Feed Annual Report 2003 (New Delhi: 2003); U.N. Population Division, op. cit. note 5; USDA, op. cit. note 1.
12. Richard Magleby, “Soil Management and Conservation,” in USDA, Agricultural Resources and Environmental Indicators 2003 (Washington, DC: February 2003), Chapter 4.2, p. 14.
13. USDA, op. cit. note 1; Randall D. Schnepf et al., Agriculture in Brazil and Argentina (Washington, DC: USDA Economic Research Service (ERS), 2001), pp. 8-10.
14. FAO, ResourceSTAT, electronic database, at faostat.fao.org/site/ 405/default.aspx, updated 30 June 2007; USDA, op. cit. note 1.
15. Pedro Sanchez, “The Climate Change–Soil Fertility–Food Security Nexus,” summary note (Bonn: International Food Policy Research Institute, 4 September 2001).
16. Edward Cody, “Chinese Lawmakers Approve Measure to Protect Private Property Rights,” Washington Post, 17 March 2007; Jim Yardley, “ China Nears Passage of Landmark Property Law,” New York Times, 9 March 2007; Zhu Keliang and Roy Prosterman, “From Land Rights to Economic Boom,” China Business Review, July–August 2006.
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