Lester R. Brown
Chapter 3. Eroding Soils and Shrinking Cropland: Grainland Gains and Losses
The world grain area expanded from 587 million hectares in 1950 to its historical peak of 732 million hectares in 1981. Since then, however, grainland has shrunk, dropping to 647 million hectares in 2002. The first large expansion in grainland after World War II came in the late 1950s with the Soviet Virgin Lands project. Concentrated in what is now the Republic of Kazakhstan, this involved plowing vast areas of grassland with only marginal rainfall. Within a matter of years, the area cleared for grain exceeded the wheat area in Canada and Australia combined. It was a massive expansion, but it was not ecologically sustainable.40
Another major contributor to the expansion of harvested area was the growth in irrigation, which both brought arid land under cultivation and facilitated double cropping. With irrigation, countries with moderate climates could often raise a second crop during the dry season. This enabled northern India, for example, to double crop wheat and rice. On the North China Plain, it enabled farmers to double crop wheat and corn. And in parts of southern China and southern India, rice could be double cropped and even occasionally triple cropped. As the century neared its end, the growth in irrigation slowed and in some countries, such as Saudi Arabia, the irrigated land area began to shrink.41
Over the last two decades, some countries that had overplowed were forced to pull back. Kazakhstan's grain area, which was roughly 25 million hectares in 1980, had shrunk to 12 million hectares by 2000. In the United States, the Conservation Reserve Program was created in the 1985 Food Security Act to convert highly erodible cropland back into grass or trees. This program retired some 14 million hectares, roughly one tenth of U.S. cropland, from 1985 onward.42
As the last century was ending, the Chinese government, concerned about the dust bowl forming in the country's northwest, launched a conservation program similar to that of the United States—one designed to help farmers plant some 10 million hectares of highly erodible grainland in trees. In addition to this planned cropland retirement, China is losing land for other reasons, as noted earlier. Between 1997 and 2002, its grain harvested area shrank from 90 million to 81 million hectares, partly from irrigation water shortages and the resultant decline in double cropping and partly from desert encroachment. By crop, more than 7 million hectares of the decline was of wheat and 2 million was of rice.43
Cropland is also being converted to fish ponds. China, producer of more than 20 million tons of farmed fish, which is roughly two thirds of the global total, has devoted 5 million hectares of land—much of it cropland—to fish ponds. Dominated by a sophisticated freshwater carp polyculture, this activity is continuing to expand. In the United States, where aquaculture is dominated by catfish, some 44,000 hectares (109,000 acres) of land in Mississippi are devoted to catfish ponds. Much of this bottomland was once used to grow rice.44
In this new century, some rainforest is being cleared for oil palm production in Malaysia and Indonesia, but by far the largest cropland expansion initiative under way today is in Brazil to the south and west of the Amazon basin. This savannah-like land, known as the cerrado, is being cleared by Brazilian farmers as they both respond to the soaring world demand for soybeans and feed a domestic population of 176 million, which is growing and becoming more affluent. Thus far, land cleared in the cerrado has been used largely to produce soybeans. This, combined with a shift of grainland to soybeans, has expanded the soybean area from 10 million hectares in 1990 to nearly 18 million in 2002.45
This land expansion, combined with rising yields, has tripled Brazil's soybean harvest since 1990, putting it in a position to soon eclipse the United States as the world's leading soybean producer and exporter. Although the cerrado appears well adapted to producing soybeans, it has not yet contributed much to expanding the world grain harvest. It might, however, do so if its farmers adopt a two-year rotation with soybeans and corn, similar to that used in the U.S. Corn Belt.46
Argentina is also contributing to the surge in world soybean output by shifting land from grain and by plowing its grasslands. But this grassland cannot be extensively plowed without encountering serious erosion and wildlife problems.
Brazil's expansion into the cerrado stands alone in the early twenty-first century as the only large-scale initiative to increase the world's cropland, one that could exceed in scale the Soviet Virgin Lands project of a half-century ago. If earlier expansion efforts in other countries are any guide, however, Brazil will also overexpand and be forced at some point to pull back.47
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