According to a report released by the China Geological Survey (CGS), the country's largest geoscience agency, 7.6 million hectares of arable land - roughly the size of Ireland - have been affected by lead and other heavy metals.
Nearly one third of that total is categorized as moderately or severely contaminated.
Yang Zhongfang, a member on the report's expert panel, says much of the pollution is in the south of China.
"Much of the heavy metal pollution can be found in the south, which accounts for approximately 73 percent of such contamination nationwide. Secondly, there has been a noticeable emergence of multiple metal contamination. That is, the soil in a single region is affected by more than one heavy metal. Thirdly, the cause of the contamination was extremely complicated, with the heavy metals coming from a variety of sources".
The pollution is also threatening land used to grow high-yield grain in China's northeastern provinces of Heilongjiang, Jilin, and Liaoning.
"China's northeast region is home to one of the world's three largest black earth belts, but the soil there has lost about 22 percent of its organic matter over the past 30 years, significantly lowering soil fertility and exacerbating the effects of heavy metal pollution".
Meanwhile, soil alkalinity and acidification are becoming serious problems in China due to both man-made and natural causes.
In response, Chinese geologists are calling for clearer rules and supportive measures to treat polluted farmland and groundwater.
Xiao Guiyi is deputy director of the geological investigation department at China Geological Survey.
"We are going to do a detailed survey on heavily contaminated farmlands as well as those that are of high quality, so that we can accurately map where they lie and offer advice to local governments on farmland planning and protection. We will also ask local governments at all levels to step up controls on heavy metal pollution, and to prevent further expansion of the contaminated land".
The Land and Resources Ministry revealed that the land treatment industry accounts for less than 1 percent of the total output of the environmental protection sector. In some developed countries, this proportion surpasses 30 percent.
For CRI, I'm Wang Wei.
