BEIJING, Jan. 22 -- Arable land contaminated by heavy metals across China will be withdrawn from agricultural production, said a senior Chinese agricultural official on Wednesday.

Agricultural land with high levels of heavy metals will no longer be used, said Chen Xiwen, deputy director of the central agricultural work leading team, the top agriculture authority.

Farm land near river sources, especially drinking water sources, will also retreat from production if use of fertilizers and pesticides may cause pollution, he added.

China will start pilot restoration of contaminated farmland this year, according to "No.1 Central Document", the first policy document of 2014, issued on Sunday.

A comprehensive plan to address prominent agricultural and environmental obstructions to sustainable development is also in the pipeline.

The "No.1 Central Document" stressed improvement to the national food security system. In recent years, excessive use of fertilizer, pesticides and plastic film combined with industrial heavy metal and chemical pollution, have hindered the sustainable development of agriculture, said Zheng Fengtian, an agriculture professor at Renmin University of China.

Excessive and improper use of resources has also affected food safety, he added.

China has an estimated 50 million mu (3.3 million hectares) of moderately or severely polluted soil, most of which is in developed and grain-producing regions, said Wang Shiyuan, vice minister of land and resources in December.

The polluted areas account for about 2 percent of total arable land which stands at some 2 billion mu.

Every year, some 12 million tonnes of grain are polluted by heavy metals in the country, according to the Environmental Protection Ministry.

China ranks first globally in total fertilizer use, and use of chemical pesticides is much higher than the world average. With a population of 1.3 billion, China has a great interest in food security and safety.

Grain output was a record high at over 600 million tonnes last year. Around 90 percent of the grain was rice, wheat and corn. However, agricultural development cannot be at a cost to the interests of future generations, said Zheng.

On the one hand, supplies of agricultural produce must be guaranteed. On the other, the quality of agricultural products should also be ensured, according to Zheng.

In the past few years, a number of heavy metal contamination incidents have been reported across China. In May last year, excessive amounts of cadmium, a carcinogen, was detected in rice products in southern Guangzhou city. Most of the toxic rice came from central Hunan Province.

Due to lax supervision and poor management, river pollution by industrial waste is common. In some rural areas, farmers irrigate their crops with water polluted by untreated waste discharged from plants. The treatment of seriously polluted land needs a lot of time, investment and technology.

China invested 9.7 billion yuan (1.6 billion U.S. dollars) in the past three years to tackle heavy metal pollution and closed more than 1,000 factories, Wu Xiaoqing, vice minister of environmental protection, said in March last year.

Some traditional farming methods, such as the use of organic fertilizers, can be promoted for sustainable development, said Zhang Hongsong, an agricultural expert in Chongqing.

Agricultural production standards in use of fertilizers and farming models can also be imposed for rehabilitation of land. The areas of farmland in need of rehabilitation occupy just a tiny part of the total arable land, and will not affect output or prices, said Zheng.