NANNING, Dec. 8 (Xinhuanet) -- China's farm produce growing areas are suffering from water, soil and atmospheric pollution which reduce the nation's grain output by approximately 40 billion kilogram every year, some Chinese agriculture experts estimate.

　　Zhang Lijian, vice-pre sident of the Chinese Academy of Agricultural Science, said pollution that threatens agricultural production comes mainly from long-term unreasonable use of such chemical compounds as fertilizer, pesticide, herbicide and growth modifiers, from improper disposal of animal excerement, and from waste from the farm land.

　　Other pollutant sources include irrigation with industrial and domestic sewage, discharge of extra solid, liquid and gasiform wastes and acid rain, Zhang added.

　　Currently, China's arable land is beset with degradation and a decline in fertility, of which farm land with low yield accounts for 40 percent. Of total land that has been polluted, farmland accounts for one sixth, with a high content of organic farm chemical residues, said Zhang.

　　According to the State Administration of Environmental Protection, approximately 6.5-7 million hectares of farm land were irrigated with industrial and domestic sewage.

　　Surveys by the Ministry of Water Resources show that areas withsoil erosion have amounted to 3.67 million square kilometers in China, or more than one third of the country's total land area. Moreover, 40 percent of land nationwide is ravaged by acid rain. Enditem