Millions of hectares of arable land in central, eastern and southern parts of China are lying unattended in winter as villagers shun agricultural life, experts said.

Rural residents are leaving the land amid rapid urbanization, according to official data.

More than 46.6 percent of arable land in 16 provinces in southern parts of China - 21.5 million hectares - lies untilled in winter, according to statistics from the Ministry of Agriculture. The land used to be planted with rice.

"Rice-planting areas in southern provinces have shrunk considerably in recent years," said researcher Lu Bu at the Chinese Academy of Agricultural Sciences' agricultural resources and regional planning institute.

"On top of this, most rice varieties that can be harvested twice a year have been replaced by single-harvest rice, as farmers are not willing to spend time on the land and want to work in the cities for more money," he said.

The average daily salary of farmers working in the cities is about 150 yuan ($25), far more than any income they could make from the land.

In some areas of Hunan province, up to 15 percent of arable land was not planted for winter crops, said Li Maosong, director of the academy's agricultural information office, citing official statistics confirmed by satellite images.

Of the national output of 546.4 million tons of grain in 2010, about 45.6 percent came from the 16 southern provinces, according to statistics from the China Agriculture Statistical Report.

The contribution from the 16 provinces marked a sharp decline from almost 60 percent in the 1980s, official figures showed.

At present, only six of the country's 31 provinces, municipalities and autonomous regions produce enough grain to support other provinces, Li said.

The 16 provinces and regions in central and southern China, with the exception of the Guangxi Zhuang autonomous region and Yunnan, depend on grain from other provinces to feed their population, he added.

An industry insider, who did not want to be identified, told China Daily that the country has been boosting shipments from the grain-rich northeast to the south in recent years, but no specific figures were provided.

Meanwhile, to meet domestic needs, China has increased grain imports in recent years, focusing global attention on the country's target for grain self-sufficiency.

The country imported 1.57 million tons of corn in 2010, a massive increase on 83,000 tons in 2009 and 49,000 tons in 2008, according to figures from the General Administration of Customs.

Wheat imports were also higher last year, rising 36 percent to 120 million tons, the customs office said.

Minister of Agriculture Han Changfu said in March that current grain imports were to adjust and enrich crop varieties in the domestic market.

"China will not, and cannot, rely on imports to feed its population," he said during an exclusive interview with Hong Kong-based Phoenix Television.

The agricultural information office's Li estimated that rice output could grow by about 10 percent if local governments made full use of arable land.

Also, more drought- and cold-resistant varieties of crops, such as potatoes and Chinese cabbage, could be planted in winter in the central and southern regions to take advantage of local climate change, he said.

"Many farmers have left the land, which is a potential risk to grain production," the academy's Lu Bu said.

"An important task for the central government is to support farmers in improving the benefits they reap from farming."

Despite unfavorable weather, China enjoyed a bumper summer harvest this year. Grain output hit 126.27 million tons, an annual increase of 2.5 percent, according to the National Bureau of Statistics.