Worse still, the total sown area devoted to food crops declined substantially from 80 percent in 1978 to just 64 percent in 2009, mainly because, with economic prosperity and rising incomes, farmers were growing more lucrative non-grain commercial crops.

Accordingly, China has come to depend heavily on increasing the output per unit of land area to maintain its food security. This, in turn, needs continual technological progress, such as using hybrids or other high-yielding varieties, and increasing intensification of cultivation with greater use of modern inputs like chemical fertilizers and pesticide.

The trouble is that barring the use of genetically modified (GM) crops, the productivity growth potential of traditional technological progress based on modern seeds and modern inputs has started to slow down everywhere in the world. Widespread use of modern inputs of industrial origins also inflicts long-term ecological damage.

Rapid economic and social changes have further worked against food production. Industrialization and urbanization in China as elsewhere inevitably spell agricultural decline. Farming is also becoming economically and socially unattractive to young people. As in other densely populated East Asian economies with severe land constraints, food production in China has also become an increasingly high-cost business.

With China having achieved successful industrial take-off, economic theory suggests that it should have a stronger comparative advantage to export labor-intensive manufactured products to the United States in exchange for its cheaper food produced by land-extensive farming. In other words, China should scale down its existing high level of food self-sufficiency and let international trade take care of any shortfalls, much as Japan has done.

However, the world has a stake in China's strong food security. If China followed the economic theory of comparative advantage by relying on international trade to achieve its food security, its import requirement would seriously destabilize the international grain market and drive up world inflation.

It is therefore in the favor of the whole world for China to rigidly adhere to its basic tenet of maintaining strong food self-sufficiency.

The author is director of the East Asian Institute, Singapore.

(China Daily 05/31/2011 page8)