By Mark Kinver
China’s scarce water supply is being wasted as crops grown in water-stressed provinces are exported to wet, rainfall-rich areas, a study reports.
Farming accounts for about 65% of water use in China and the limited resource is coming under pressure from rapid urbanisation and industrialisation.
Officials have called the nation’s water shortage a “grave situation” and called for strict water controls.
“China faces most of the major challenges to sustainable agriculture,” wrote an international team of researchers.
“Fast socioeconomic development, rapid urbanisation and climate change, along with very limited water resources and arable land per capita,” they added.
“Because arable land is available mainly in the water-scarce north, irrigation has become widespread, covering 45% of the country’s agricultural land and accounting for 65% of national water withdrawal.
The study focused on four major food crops – soya, wheat, rice and corn (maize) – and three livestock groups: ruminant, pork and poultry.
Together, these products accounted for 93% of China’s domestic food supply in 2005, according to figures from the United Nations.
The team – involving scientists from the US, Japan and China – assessed the volume of water used by different provinces to produce these crops and livestock, including the volume from rainwater and irrigation systems.
They concluded: “China’s domestic food trade is efficient in terms of rainwater but inefficient regarding irrigation, meaning that dry, irrigation-intensive provinces tend to export to wetter, less irrigation-intensive ones.
“We (also) identify specific provinces (for example, Inner Mongolia) and products (for example, corn) that show high potential for irrigation productivity improvements.
The team added that the paper’s findings had important policy implications.