Beijing, July 18 (IANS) The high usage of chemicals is posing a threat to China's grain output, experts have warned.

China's grain production hit 546.4 million tonnes in 2010 despite floods and droughts.

"But this (grain growth) will not last long if the government fails to take timely and effective measures, as the soil is already too poor to support high-yield crops," China Daily qouted Jiang Gaoming, a researcher at the Chinese Academy of Sciences, as saying.

Jiang said the problems being faced are the result of massive overuse of chemical fertilizers over the past 30 years.

In China, the annual grain output increased from 320.56 million tonnes in 1980 to 546.4 million tonnes in 2010.

Also, since the past four years China has been the world's largest consumer of chemical fertilizers.

Jiang said: "More chemical fertilizer, more grain output - that's been a common misunderstanding among government officials and farmers for dozens of years. Crops were always fertilized, regardless of cost, to guarantee high production."

Another expert Li Shilin, who is the director of an agricultural technical station, said: "Farmers usually only care about crop output and income. They seldom consider the soil damage and potential risks to human health from overusing fertilizers."