A farmer collects potatoes in the field in the Saibei Administration Area in Zhangjiakou City, north China's Hebei Province, Sept 22, 2014. The Sabei area, which has about 50,000 mu (about 3,333 hectares) of potato field, is expected to yield more than 100,000 metric tons of potatoes. [Photo/Xinhua]

China is boosting potato acreage to transform the crop into the country's fourth staple food after rice, wheat and corn, said Yu Xinrong, vice minister of agriculture, at a seminar on Tuesday.

It is time for potatoes to become a staple food, given China's rapid urbanization, and they can diversify the dinner table, said Wan Baorui, director of China's state food and nutrition consultant committee.

The potato has been grown for about 400 years in China and now covers 5 million hectares in China, according to the Ministry of Agriculture. Acreage will expand to 10 million hectares in the future to better safeguard the country's grain supply, according to the ministry.

The country will see 50 billion kilograms of new food demand by 2020. China has a shortage of farmland and it is hard to improve the yield efficiency of wheat and rice, but it is easier to improve with potatoes, according to the ministry.

The country has set a "red line" minimum of 120 million hectares of cultivated land, but pressure on arable land is still great, largely due to rapid urbanization.