"Eliminating water shortages depends on a global attempt to raise water productivity similar to the effort launched a half-century ago to raise land productivity, an initiative that has nearly tripled the world grain yield per hectare." –Lester R. Brown, World Facing Huge New Challenge on Food Front in Plan B 3.0: Mobilizing to Save Civilization
Part 1. Assessing the Food Prospect: Future Food Security
Future food security depends on expanding many ongoing activities such as agricultural research, agricultural extension, farm credit (especially microcredit programs designed for small farmers in developing countries), and the support prices that stabilize prices and encourage farmers to invest in land improvement. The keys to future food security now are to eliminate the soil deficit and the water deficit and to stabilize population and climate.
Reducing soil losses below the rate of new soil formation is possible, but it will take an enormous worldwide effort. Based on the experience of key food-producing countries such as China, the United States, and numerous smaller countries, easily 5 percent of the world’s cropland is highly erodible and should be converted back to grass or trees before it becomes wasteland. The first step is to pull back from the fast-deteriorating margin. 48
Wind erosion is concentrated in arid and semiarid regions, while water erosion is concentrated on sloping lands in regions with higher rainfall. Wind erosion, common on cropland and rangelands, is the source of dust and sand storms. Water erosion is the source of the silt that raises riverbeds, fills irrigation and hydroelectric reservoirs, clogs harbors, and suffocates marine ecosystems.
The key to controlling wind erosion is to keep the land covered with vegetation as much as possible and to slow wind speeds at ground level. Ground-level wind speeds can be slowed with shrubs, trees, and crop residues left on the surface of the soil. For areas that are particularly rich in wind and in need of electricity, such as northwestern China, wind turbines can simultaneously slow wind speed and provide cheap electricity. This approach converts a liability—strong winds—into an asset.
One of the time-tested methods of dealing with water erosion is terracing, as is so common with rice paddies in the mountainous regions of Asia. On land that is less steeply sloping, contour farming as in the midwestern United States has worked well.
Another tool, a relatively new one, in the soil conservation toolkit is conservation tillage, which includes both no tillage and minimum tillage. After being taught that seedbeds required plowing and careful preparation prior to planting, farmers are now learning that less tillage may be better. Instead of plowing land, then discing or harrowing it to prepare the seedbed, then planting with a seeder and cultivating row crops with a cultivator two or three times to control weeds, farmers simply drill seeds directly into the land without any preparation at all. Weeds are controlled with herbicides. This means the only tillage is often a one-time disturbance in a narrow band of soil where the seeds are inserted, leaving the remainder of the soil undisturbed. 49
This practice, now widely used in the production of corn and soybeans in the United States, has spread rapidly in the western hemisphere over the last few decades. (See Table 1–6.) Data for crop year 1998/99 show the United States with 19.3 million hectares of land under no-till. Brazil had 11.2 million hectares, and Argentina 7.3 million hectares. Canada, at 4 million hectares, rounds out the “big four.”
In the United States, the combination of retiring the highly erodible land under the CRP and shifting part of the remaining land in row crops to conservation tillage has sharply reduced soil erosion. By 2000, U.S. farmers were no-tilling 21 million hectares (51 million acres) of crops. An additional 23 million hectares were minimum-tilled, for a total of 44 million hectares of conservation tillage. This was used on 12 million hectares (30 million acres) of corn—or 37 percent of the crop. For soybeans, it was 17 million hectares—57 percent of the crop. For wheat and other small grain crops, the conservation tillage area totaled 11 million hectares (30 percent of the planted area). 50
Once farmers begin to practice no-till, its use can spread rapidly. In the United States, the no-till area went from 7 million hectares in 1990 to nearly 21 million hectares in 2000, tripling within a decade. 51
Recent U.N. Food and Agriculture Organization reports describe the growth in no-till farming over the last few years in Europe, Africa, and Asia. In addition to reducing both wind and water erosion, and particularly the latter, this practice also helps retain water and reduces the energy needed for crop cultivation. 52
While the soil deficit has been building over the last few centuries, the water deficit is much more recent, a product of the half-century or so since diesel and electrically powered pumps have become widely available for irrigation. And, as noted earlier, it is growing fast.
The potential disruption of world grain markets by water shortages calls for a global effort to raise water productivity, an effort similar to that launched 50 years ago regarding land. When it was realized after World War II that there was not much new land to bring under the plow, a worldwide effort was undertaken to raise land productivity. It included heavy investment in agricultural research to raise crop yields, the development of agricultural extension services to disseminate the research results to farmers, and the adoption of support prices to stabilize prices of farm commodities. This effort was highly successful, boosting world land productivity from 1.1 tons of grain per hectare worldwide in 1950 to 2.7 tons per hectare in 2001. 53
Future food security now depends on raising water productivity not only in agriculture but in all sectors of the economy—ranging from more water-efficient household appliances to more water-efficient irrigation systems. Of all the policy steps to raise water efficiency, by far the most important is establishing a price for water that will reflect its value to society. Because water policies evolved in an earlier age, when water was relatively abundant, the world today is sadly lacking in policies that reflect reality. Raising the price of water to reflect its value would affect decisions involving its use at all levels and in all sectors. To be successful, the price should go up in concert with what some countries describe as “lifeline rates,” where individual residences get the amount of water needed to satisfy basic needs at an easily affordable price. But once water consumption exceeds this minimum needs level, then the cost would escalate, thus encouraging investment in water efficiency.
The underpricing of water permeates water systems throughout the world. Some governments, such as India, heavily subsidize the use of irrigation water by providing electricity for pumping water to farmers at a nominal cost. 54
Since 70 percent of all water that is diverted from rivers or pumped from underground is used for irrigation, investment in more water-efficient irrigation practices and technologies is central to any effective strategy to raise water productivity. In simplest terms, this means shifting from less water-efficient flood or furrow irrigation to more-efficient sprinkler and drip irrigation. Drip irrigation—now used on some 2.4 million hectares of cropland worldwide—can easily reduce irrigation water use by half while boosting yields. Its drawback is that it is much more labor-intensive. But in countries with widespread unemployment, switching to drip irrigation for many crops would simultaneously raise water productivity and employment. Although drip irrigation is not economic in all situations, there are many where it is economic but not yet used. 55
There is also the possibility of adopting irrigation practices that use water more efficiently. In some situations, for example, rice need not be permanently flooded throughout the growing season but can be flooded periodically without any loss in yield. 56
Cropping patterns are also being altered to favor more water-efficient crops. Both Egypt and China restrict the production of rice because of its high water requirements, favoring wheat instead. Anything that raises the efficiency of grain conversion into animal protein also raises water efficiency.
For those who are living high on the food chain—that is, who are consuming excessive amounts of fat-rich livestock products—moving “down” the food chain will both improve personal health and lower grain use and, therefore, water use. Consuming less fat also reduces obesity and the associated costs of treating obesity-related illnesses.
A third step to enhance future food security is to stabilize world population growth sooner rather than later. Current U.N. projections for 2050 range from a low projection of 7.9 billion to the high of 10.9 billion. The prospects of everyone having enough food will be greatly enhanced if the world can reach only the lower number. Even with existing populations, many developing countries do not have enough water to meet basic needs. What happens if their populations double again, as some are projected to do in the next few decades? The key now is to invest in the education of young females throughout the developing world and to improve the status of women by giving them the same ownership, inheritance, and voting rights as men. This, combined with filling the family planning gap, so that couples everywhere have access to family planning services, is the key to future food security and to making sure that people everywhere will have enough food to develop their full physical and mental potential. 57
The other key to future food security is climate stabilization. World agriculture as it exists today evolved over 11,000 years during a period when climate was remarkably stable. If temperature and rainfall levels and patterns begin to change, agriculture as it currently exists will be out of sync with the ecosystem, forcing the need for constant adjustment as the climate system itself changes. Climate change is now the wild card in the food security deck of cards.
|Table 1-6. Cropland Area Under No-Till in Key Countries, 1998/99|
|Source: Rolf Derpsch, "Frontiers in Conservation Tillage and Advances in Conservation Practice," in D.E. Stott, R.H. Mohtar, and G.C. Steinhardt (eds.), Sustaining the Global Farm (2001), pp. 248-54.|
48. U.S. experience in USDA, op. cit. note 13; USDA, op. cit. note 14; China from Chen, op. cit. note 14.
49. USDA, Natural Resources Conservation Service, CORE4 Conservation Practices Training Guide: The Common Sense Approach to Natural Resource Conservation (Washington, DC: August 1999); Rolf Derpsch, “Frontiers in Conservation Tillage and Advances in Conservation Practice,” in Stott, Mohtar, and Steinhardt, op. cit. note 6, pp. 248–54.
50. CTIC, “2000 United States Summary,” from 2000 National Crop Residue Management Survey, at <www.ctic.purdue. edu/Core4/CT/ctsurvey/2000/2000USSummary.html>, updated 20 January 2002.
51. CTIC, “No-Till Adoption in the U.S.,” from 2000 National Crop Residue Management Survey, at <www.ctic.purdue. edu/Core4/CT/ctsurvey/2000/GraphNTAll.html>, updated 20 January 2002.
52. Derpsch, op. cit. note 49.
53. USDA, op. cit. note 12.
54. Sandra Postel, Last Oasis (New York: W.W. Norton & Company, 1997), p. 170.
55. Diversion of 70 percent from Gleick, op. cit. note 5, p. 64; Sandra Postel, “Redesigning Irrigated Agriculture,” in Lester Brown et al., State of the World 2000 (New York: W.W. Norton & Company, 2000); Sandra Postel et al., “Drip Irrigation for Small Farmers: A New Initiative to Alleviate Hunger and Poverty,” Water International, March 2001, pp. 3–13.
56. Postel, op. cit. note 21, pp. 189–92.
57. Population projections in United Nations, op. cit. note 2.
Copyright © 2002 Earth Policy Institute