Recently, there have been rumors that China's self-sufficiency in grain has plunged below 90 percent.

Authorities have refuted such rumors and said the self-sufficiency rate for major grains remains above 97 percent.

However, this conclusion was drawn after the 58 million tons of soybeans, which make up 72.8 percent of grain imports, were deducted from the calculations.

China buys 60 percent of soybeans exported globally. If we don't take this seriously, we may underestimate the country's food security issue.

It needs a long-term perspective to review China's food security issue. If the import volume of grain exceeds 10 percent of the production volume only in one or two years, we cannot say that the reliance rate on foreign grain is already over 10 percent. We should take special situations into consideration.

In 2012, the import volume of corn, wheat and rice took up less than 2 percent of their national production volume, a sign of food security in China.

The long-term plan is that China should remain self-sufficient in rice and wheat, especially rice.

The self-sufficiency rate for grain needs detailed standards. First, the varieties of grain in which China can be self-sufficient needs to be refined.

Meanwhile, we should allow the rate to change over a particular period, for instance, from 2008 to 2020. We can make adjustment to the rate, and evaluate the rate used in practice.

And for the next stage, say after 2020, we can slightly adjust the rate.

China's self-sufficiency in grain faces tough challenges from urbanization.

Urbanization will bring problems, like the loss of arable land. Meanwhile, the amount of crops used for forage or industrial purposes will increase accordingly.

The increased rate of grain production can hardly catch up with the increased rate of the demand for agricultural products including grain.

We don't have to be over-conscious about some Western media reports that China has increased the import volume of rice recently. But we should be aware of the potential consequences of rice imports.

Some hold that China's imported rice only consists less than 2 percent of the national production volume and 6 percent of the global trade volume.

However, every 1 percent of the national grain demand we import equals 2 percent of the international grain trade volume. If we import too much, the international market will not bear it, and it will affect poorer countries.

China should remain highly self-sufficient in grain production. This can be argued, but cannot be changed for a long time.

We should increase the production volume of grain through difference processes, such as purchasing grain and setting stable prices. Meanwhile, we should reduce or at least not expand the import volume. By doing so, we could properly solve the national grain problem and raise the self-sufficiency rate for grain.

The author is deputy director of the Hunan Administration of Grain and a senior economist. opinion@globaltimes.com.cn