The country's summer grain output inched down 0.3 percent from one year earlier to 123.1 million tons in the first half of this year after a prolonged drought in southwest China. It was the first decline in seven years for China's summer grain output.

To ensure grain security, China set a "red line" to guarantee its arable land never shrinks to less than 120 million hectares.

According to statistics from China's Ministry of Land and Resources, the country is already edging dangerously close to its "red line," with just 121.7 million hectares available as of the end of last year.

China lost 8.2 million hectares of arable land from 1997 to 2009.

Analysts believed several major factors contributed to the arable land loss, such as increasing use of arable land for construction purposes, forest or grassland replanting programs as well as damage caused by natural disasters.