Erosion of the black soil in China's chief agricultural area has caused crop failures, a Ministry of Water Resources taskforce reports. The black soil zone, covering one million sq. km of Heilongjiang, Jilin and Liaoning provinces as well as Inner Mongolia, is one of the world's most fertile areas. But over the past 10 years, wind and water erosion has led to a loss of nutrients and the soil has thinned. As a result, crop production in Heilongjiang dropped from 4.5 million tonnes to 2.5 million tonnes this year, despite the use of extra fertiliser. A taskforce spokesman said researchers were looking for solutions.