Increasing water shortages in China could have implications for cotton and wheat production in the United States and elsewhere, USDA analysts say in a report released at the annual Agricultural Outlook Forum at Arlington, Va.
China is the world's largest wheat-producing country and a decrease in production could have a significant impact on international markets.
“Cropping patterns in China will likely change as farmers address water conservation issues,” says the Interagency Agricultural Projections Committee, which outlined its projections for the period to 2013. “Effective conservation policies will induce farmers to use water in ways that are more in accordance with its economic value in production.”
Water uses that bring a low return, such as wheat irrigation, are likely to be replaced by uses that provide higher returns, such as cotton, with lower irrigation needs.
The introduction of Bt cotton in the North China Plain region has also made cotton much more profitable in that area.
“Because of the profitability of Bt cotton, and low wheat prices, increasing numbers of farmers are forgoing winter wheat and planting full-season, spring-sown cotton instead, which they irrigate one to three times before the rainy season begins.
“In addition, cotton tends to be more salt-tolerant than wheat, and much of the North China Plain's shallow water table has salinity problems.”
Additionally, the analysts say, some irrigated wheat land could be switched to vegetable production, using modern water-saving practices.
“A shift to vegetables would also be in accordance with China's underlying resource endowment, which is labor-abundant and land-scarce.
“If China further opens its agricultural markets, this too will hasten the shift into more labor-intensive crops that could bring higher returns from the country's limited water resources.”
Rapidly increasing industrial and domestic water consumption and expanding irrigation over the past 40 years have drawn down ground water tables and disrupted surface water deliveries, a problem that is most severe in the North China Plain area of north central China.
Over 50 percent of China's wheat and nearly 40 percent of its cotton have been produced in three provinces — Hebei, Shandong, and Henan — and both crops rely heavily on irrigation.
“Wheat is the most likely crop to experience production declines due to irrigation water shortages,” the analysts say.
Most of the wheat in the areas affected by irrigation water shortages is winter wheat, harvested in June, and followed by corn or, increasingly, cotton.
Over 70 percent of the annual rainfall on the North China Plain falls July-September, so the second crop does not rely on supplemental irrigation as much as winter wheat.
Wheat is also threatened by reduced water availability because irrigated wheat brings a low return in proportion to water costs and is less suited than horticultural crops to water-saving irrigation technologies such as drip irrigation, plastic mulching, etc.
China continues to draw down water resources, analysts say, and many observers anticipate the situation worsening unless effective conservation policies can rapidly be put into place.
A variety of policies have been established to encourage more effective water conservation in both agricultural and non-agricultural uses.
“The success of these policies,” the analysts say, “will depend on several factors. Policy reforms will depend critically on the enforcement of withdrawal limits, both from surface water systems and from ground water.
“Also important is the extent to which policies and local management practices provide water users and water managers an incentive to conserve water resources.”