HARBIN - Liu You, a farmer in Keshan County of northeast China's Heilongjiang province, stopped planting soybeans last year, due to the crop's low yield and economic return.

He grows corn instead, which yields much more than soybean and brings more income. "The price of soybeans has kept almost unchanged while the prices of corn and rice have been rising in recent years," says Liu.

In Keshan County, the plantation area of soybeans nearly halved from 2007 to 2012, showing farmers have less interest in planting the crop, a trend that is playing out in many other rural areas.

The root for the decisions taken by Liu and his peers can be found in China's rising imports of genetically modified (GM) soybeans. By virtue of the modifications, GM soybeans are more economical to produce than their conventionally-farmed equivalents. With large-scale production of GM crops not yet approved in China, domestic farmers of soybean are being priced out of the market as the country proves happy to look to imports for this most quintessential of Chinese foodstuffs.

However, this is far from the only troubling aspect of imported GM food. GM remains controversial over doubts as to its safety. As it flows into China, the country is having to face up to such questions.

Last week, China's Ministry of Agriculture announced the approval of three varieties of GM soybeans to be imported as processing materials.

The news triggered fresh domestic concerns about safety, although there has been large-scale commercial plantation of GM crops for years in the United States and many other countries.