Food Security and Globalization
Why could wheat and rice cultivation add to the problem of hunger around the world?
Archaeological evidence places the domestication of rice 9,000 years ago, most likely along the Yangtze River in eastern China.
Sedentary hunter-gatherers began cultivating the weedy ancestors of modern wheat varieties about 10,000 years ago in the Fertile Crescent around Jericho, in the southern Jordan Valley.
Over thousands of years, yield gains were eked out by the collection, selection and replanting of the best and most productive seeds, augmented by improved techniques of cultivation soil fertility management and migration to more favorable agricultural lands.
Yield increases using these methods rose slowly — though substantially — over long periods.
Starting in the late 19th century and growing more rapidly in the last half of the 20th, major crop yields in the United States and other developed countries increased at rates well above historic trends.
From an average wheat yield of 11 bushels per acre in 1866 (the earliest year for which reasonably reliable time-series data are available), 91 years were to pass before U.S. yields doubled.
Just 43 years later, yields had almost doubled again, averaging 42 bushels per acre in 2000. Wheat yields are substantially higher in Europe than in the United States, partly because of heavier fertilizer use per unit of land.
American farmers also grow primarily maize and soybeans on the best agricultural land, while wheat — a lower-value crop — is relegated to lower rainfall areas like Kansas and North Dakota.
Yield accelerations occurred in many other crops in the United States over the past century, as improved varieties spread rapidly and increasing amounts of yield-enhancing inputs were used.
These accelerations were all based on developments in the early 20th century as mainly public (as well as some private) breeding programs began applying the lessons of Mendelian genetics.
In the developing world, scientific crop breeding lagged behind. Beginning in the 1950s and 1960s, improved varieties became available to farmers and yields rose.
Wheat went from one ton per hectare or less in China and India in the mid-1960s to more than 2.5 tons in India — and almost four tons in China by the late 1990s.
Asia embraced these new varieties most rapidly, while adoption lagged in Sub-Saharan Africa.
Similar patterns of productivity growth have occurred in staple food crops the world over. Globally, yields have climbed steadily for all major cereals since the 1960s.
Although concerns have been raised that the rate of yield growth for some crops (like rice and wheat) seems to have slowed in some regions, the pattern is not uniform. Indeed, an absolute yield ceiling seems far off.
Researchers estimate that under ideal conditions, maize yields of 450 bushels and soybeans of 250 bushels per acre are a technical possibility, compared with current average U.S. yields of 128 bushels per acre for maize and 40 bushels per acre for soybeans.
But land and climate are often far from ideal and these natural inputs into agriculture are prone to degradation without careful stewardship.
Apart from yield growth, another source of gain has been the productivity of seed. In Medieval England, farmers saved one-quarter of their wheat harvest for seeding the next crop; only three-quarters remained for food and feed consumption.
In times of privation, breaking into seed maize stored for spring was punishable by death. Death was also nature's verdict if seed rotted due to fungus, as in the wet, cold summers that occurred periodically during the Middle Ages in Europe.
Over time, the ratio of seed-to-grain produced has fallen sharply. In 1961, the global average planting rate of wheat was about 11% of output. By 1999, it was only 6%.
The average planting rate of rice in 1961 was only about 5%. By 1999, it had fallen as low as 3% — as germination rates and other crop protections improved.
In addition, mechanization released land formerly needed to feed draft animals (oxen, mules, horses) for production of food and fiber. Therefore, yield growth actually underestimates the real gain in net harvest from changes in technology.
Improvements in harvesting, storage and transportation technologies have added to the food available to consumers from a given harvest by reducing losses and spoilage.
The result of these additions in production capacity has been to "save" land. Producing today's global food supply with 1960 crop yields would require an additional 300 million hectares of land.
In other words, modern farming has dramatically reduced the cropland necessary to meet demand — by an area equal to the entire land mass of Western Europe.
One important result has been to relieve areas only marginally suitable for agriculture from potentially serious environmental degradation.
Excerpted and adapted from "Ending Hunger In Our Lifetime: Food Security and Globalization" by C. Ford Runge, Benjamin Senauer, Philip G. Pardey and Mark W. Rosegrant. Copyright 2003 International Food Policy Research Institute. Used by permission of The Johns Hopkins University Press.