EPIBuilding a Sustainable Future
Outgrowing the Earth: The Food Security Challenge in an Age of Falling Water Tables and Rising Temperatures

Chapter 4. Raising the Earth’s Productivity: Future Options

In a world where it is becoming increasingly difficult to raise land productivity, we have to look for alternative ways of expanding output. One obvious approach is to increase the amount of multiple cropping—growing more than one crop on a field per year. Yet this is not easy, and in some East Asian countries, such as Japan, South Korea, Taiwan, and, more recently, China, it is already declining. 47

Devising economic incentives to sustain multiple cropping in some countries and expand it in others could help buy time to stabilize world population size. For countries in East Asia, the challenge is to provide economic incentives to farmers so as to avoid, or at least slow, the decline in double cropping. In the United States, in contrast, where the overriding concern for half a century was to control production by restricting the area planted to grain, the potential for more multiple cropping may be surprisingly large. Here economic incentives for double cropping could boost output. One of the keys to exploiting this lies in reorienting agricultural research programs to develop facilitating technologies such as earlier maturing crops and farm practices that will accelerate the harvesting of the first crop and the planting of the second one.

Another way to expand food production is to raise water productivity. This helps both to preserve the existing irrigated area, where water supplies are tightening, and to expand the area irrigated in other places. The water available for irrigation can also be increased at the local level by building small water-harvesting ponds. These not only capture rainfall runoff, holding it for irrigation, they also help recharge underground aquifers.

Land productivity can be raised by using crop residues to produce food. For example, the tonnage of wheat straw, rice straw, and corn stalks produced worldwide easily matches the weight of the grain produced by these crops. As India has demonstrated with its world leadership in milk production, and as China is showing with its surging beef production, it is now possible to feed these vast quantities of crop residues to animals, converting them into milk and meat. In effect, this permits a “second harvest” from the same land. 48

In some parts of the world, such as Africa, investment in transportation and storage infrastructure can play a major role in boosting food production, enabling farmers to move beyond subsistence agriculture. This is particularly helpful in both getting inputs such as fertilizer to farmers and getting their harvest to markets. 49

Jules Pretty, director of the Centre for Environment and Society at the University of Essex, has pioneered a broad concept of sustainable agriculture, one that strives to develop natural, human, and social capital at the local level. It emphasizes the use of local resources. Sustainable farming, says Pretty, “seeks to make the best use of nature’s goods and services. It minimizes the use of non-renewable inputs (pesticides and fertilizers) that damage the environment.... It makes better use of the knowledge and skills of farmers.” 50

In reviewing the results of some 45 sustainable agriculture initiatives in 17 African countries, Pretty notes that both crop yields and nutritional levels improved more or less apace. Overall, he notes that crop yields are up 50–100 percent in these projects over 20 years. 51

Included in the sustainable agriculture toolbox is the better use of local natural resources and processes like nutrient cycling, nitrogen fixation, soil rebuilding, and the use of natural enemies to control pests. This approach does not rule out the use of fertilizer and pesticides but seeks to minimize the need for their use. The use of leguminous plants to supply nitrogen is seen as an intrinsic part of the process. Animal manures are collected to fertilize fields and build up soil organic matter. This, in turn, increases soil moisture retention.

The emphasis on human capital leads to greater self-reliance by farmers. Learning centers and extension offices play an important role in the communities with successful sustainable agriculture. With social capital, the key is getting people to work together, in groups, to better manage watersheds and local forests or to supply credit to small-scale farmers.

With this approach, communities with marginal land have succeeded not only in raising incomes and improving diets, but also in producing a marketable surplus of farm products. Highly successful though this approach is, it does require substantial support to energize local communities. Pretty notes that “without appropriate policy support, [these community projects] are likely to remain localized in extent, and at worst simply wither away.” 52

The challenge is to raise land productivity in one way or another and to design research programs to do this while protecting the land and water resource base and avoiding damage to natural systems, such as that caused by nutrient runoff.

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47. Brown, op. cit. note 24, p. 61.

48. Roughage conversion from A. Banerjee, “Dairying Systems in India,” World Animal Review, vol. 79, no. 2 (1994), and from S. C. Dhall and Meena Dhall, “Dairy Industry—India’s Strength in Its Livestock,” Business Line (Internet Edition of Financial Daily from The Hindu group of publications), 7 November 1997; China’s crop residue production and use from Gao Tengyun, “Treatment and Utilization of Crop Straw and Stover in China,” Livestock Research for Rural Development, February 2000.

49. Norman E. Borlaug, “The Next Green Revolution,” New York Times, 11 July 2003.

50. Jules Pretty and Rachel Hine, “Reducing Food Poverty with Sustainable Agriculture: A Summary of New Evidence,” final report from the “SAFE-World” (The Potential of Sustainable Agriculture to Feed the World) Research Project (Colchester, UK: University of Essex, February 2001), p. 11.

51. Ibid.; “Famine in Africa: Controlling Their Own Destiny,” (London) Guardian, 30 November 2002.

52. Pretty and Hine, op. cit. note 50, p. 21.


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