FARMERS' fields are a far bigger source of water contamination in China than factory effluent, according to findings of a survey conducted by the Chinese government.

Senior officials said the disclosure, after a two-year study involving 570,000 people, would require a partial realignment of environmental policy from smoke stacks to chicken coops, cow sheds and fruit orchards.

Despite the sharp upward revision of figures on rural contamination, the government suggested the country's pollution problem may be close to - or even past - a peak. That claim is likely to prompt scepticism among environmental groups.

According to insiders, the release of the groundbreaking report was delayed by resistance from the agriculture ministry, which had previously insisted that farms contributed only a tiny fraction of pollution in China.

The census disproves these claims completely. According to the study, agriculture is responsible for 43.7 per cent of the nation's chemical oxygen demand (the main measure of organic compounds in water), 67 per cent of phosphorus and 57 per cent of nitrogen discharges.

At the launch of the paper, Wang Yangliang of the ministry of agriculture recognised the fallout from intensive farming methods.

“Fertilisers and pesticides have played an important role in enhancing productivity, but in certain areas improper use has had a grave impact on the environment,” he said. “The fast development of livestock breeding and aquaculture has produced a lot of food, but they are also major sources of pollution in our lives.”

He said the ministry would introduce measures to improve the efficiency of pesticide and fertiliser use, to expand biogas generation from animal waste, and to change agricultural lifestyles to protect the environment.

While the high figure for rural pollution is partly explained by the immense size of China's agricultural sector, it also reflects the country's massive dependency on artificial farm inputs such as fertilisers.

The government says this is necessary because China uses only seven per cent of the world's land to feed 22 per cent of the global population.

An industrial lobby is pushing for even greater use of chemicals. It includes the huge power company CNOOC, which runs the country's largest nitrogen fertiliser factory in Hainan's Dongfang City.

But the returns on this chemical investment are poor. According to a recent Greenpeace report, the country consumes 35 per cent of the world's nitrogen fertiliser, which wastes energy and other resources, while adding to water pollution and greenhouse gas emissions.

“Agricultural pollution has become one of China's gravest environmental crises,” said Greenpeace campaign director Sze Pangcheung. “China needs to step up the fight against the overuse of fertilisers and pesticides and promote ecological agriculture which has obvious advantages for human health, the environment, and sustainable development of agriculture.”

Wen Tiejun, dean of the school of agriculture and rural development at Renmin university, said the survey should be used as a turning point.

— The Guardian, London