When American scholar Lester Brown questioned China's food security, he was asking whether this country's agriculture could yield enough to fill the one-billion-plus stomachs.

That quite recent fear of scarcity now seems belong to another age. We now have more than enough to eat.

The speed at which our dinner tables and diets are being enriched and refreshed is amazing.

While enjoying such abundance, most of us express regret that many things seem to have lost its original flavour. And many have rightfully attributed such insipidness to the overuse of agricultural chemicals.

But chemicals do more than contribute to the overall blandness of our food. Addictive reliance on farm chemicals, including but not limited to chemical fertilizers and pesticides, is turning agriculture as an industry into a major source of pollution in this country, experts say.

Chinese farmers use more than 400 kilograms of chemical fertilizers on every hectare of farmland, far exceeding the upper limit of 225 kilograms considered safe in developed countries.

Chemical fertilizers may help plant growth and raise per-unit output. But some of their ingredients, particularly nitrogen and phosphorus, can also cause damage. When there is more nitrogen than crops can assimilate, the surplus will contaminate underground water, rivers, lakes, and the sea, and thus our major source of drinking water. High nitrogen concentration in water results in excessive nitrates, which may prove poisonous and induce cancer. 

In addition, nitrogenous fertilizers are an important cause of nitrous oxide, one of the three major greenhouse gases.

A direct impact of nitrogen on the soil is to make it acidify and crust over. That reduces productivity.

The economic losses and environmental damage resulting from the inefficient use of nitrogenous fertilizers are a global problem.

As our population grows and the area of cultivated land shrinks, our farmers may depend more heavily on such fertilizers to ensure higher yields.

Many, including some mainstream experts, have their eyes on nitrogenous fertilizers to work that magic.

But that is a suicidal course.

As early as 2004, Chinese and overseas scientists jointly warned of the threats that abusive use of chemical fertilizers pose to human health and the environment.

They found that half of the nitrogenous fertilizer used in China had already evaporated into the air or drained into the water system before being absorbed by crops, causing serious potential damage.

That is a serious problem that should have been an important aspect of our rhetoric about "green GDP."

It would be ridiculous if we continued to neglect agriculture-induced pollution while reining in polluting factories.

Besides quantity-related security, we should care more about the safety of our food chain.

In order to prevent hazardous substances from accumulating further on our dinner tables, the authorities must do more to educate our farmers about scientific use of farm chemicals.