Getting to the root of killer dust storms
Dust storms have increased sixfold over the past twenty years in northern China because of population growth and increasing numbers of livestock. The storms cause respiratory illness, destroy crops and blow away precious topsoil.
Dennis Normile reports in Science how one village has reduced numbers of dust storms in the area by reducing herd sizes and restoring degraded pastureland.
Dust storms occur when intense grazing strips pastureland of new growth, leaving the topsoil vulnerable to winds.
Strategies across China to tame the deserts — by planting trees and developing artificial oases in arid regions — have, on the whole, not been successful, and may have added to the problem.
In the area around Bayinhushu, a village 180 kilometres north of Beijing, herds have increased from one million in the 1940s to over 24 million in 2000, and villagers have reported increasing dust storms and pasturelands turned to dust.
But plant ecologist Jiang Gaoming from the Chinese Academy of Sciences persuaded the villagers of Bayinhushu to reduce sheep and goat numbers, and to stop open grazing.
After five years, the grassland has been restored and dust storms have lessened. Milk production has doubled and annual incomes have increased.
The next battle will be rehabilitating more arid areas of China. Scientists are recommending intervention — sand barriers and planting soil-stabilising plants — as well as introducing water-conservation techniques to allow sustainable farming.
Reference: Science 317, 314 (2007)