The problem with cotton

Genetic engineering was supposed to bring much-needed help to cotton farmers in China, but the benefits were very short-lived. Jiang Gaoming and Li Caihong report from north China’s cotton heartland.

On the plains of northern China is a county known as “the home of cotton”. During the harvest, white cotton buds sway in the breeze, stretching as far as the eye can see; 400 square kilometres (600,000 mu)are covered with the plant. This scene has become a common one in China since the start of the reform era in the 1980s, and local cotton farmers have filled their wallets on the proceeds.

In the 1990s, however, an outbreak of bollworm shattered the dreams of riches that many harboured in the region. After this plague, far less cotton was planted. Despite government rulings that aimed to bolster the cotton industry, farmers did not want to take the risk, turning pale at the prospect of losing another harvest to pests. There was no more cotton planted in the area for several years.

This only changed at the end of the last decade, when genetic engineers developed a pest-resistant strain of cotton. And at first it worked. Cotton planting started to recover. The pests were smaller and less pesticide was used. Production rose and profits increased; farmers wanted to plant cotton again.

But as time passed, pest-resistant cotton’s failings started to become apparent. The seedlings were very susceptible to diseases, and preventing these diseases meant a continued reliance on chemicals. The plants also suffered from root rot and verticillium, a wilt-causing fungus. These can be prevented by spraying the crops with chemicals, but they are hard to cure. The new strain of cotton was also not resistant to aphids, which were controlled with yet more pesticides. Today there is a wide proliferation of chemicals on the market specifically designed for cotton growers.

Even with the new cotton, pesticides still need to be sprayed every three to five days. Forty kilograms of solution is used to cover one mu of land (667 square metres), containing 60 to 100 millilitres of pure chemical pesticide. The scientists who genetically engineered this pest-resistant cotton may have succeeded in controlling the pest they were targeting, but not any of the others. The farmers remain reliant on toxic chemicals.

As soon as the cotton seeds germinate, measures must be taken to prevent bollworm attacks. This particular pest can reproduce three to five times in a single growing season, making it even harder to combat. And today’s bollworms are nothing like their predecessors, they cause far more damage. To maintain harvests and profits, the cotton farmers have no choice but to keep spraying costly chemicals.

Moreover, the bollworms have been joined by some as yet unidentified pests. Three or four years ago a new insect appeared, decimating the cotton harvest. Although small and weak-looking, they have been very damaging.

Fields in China today are battlegrounds covered with destructive chemicals. Yet despite the herbicides and pesticides, weeds and insects continue to multiply, and the chemicals are becoming ever stronger. Insects are forced to adapt faster, becoming resistant by developing thick layers of waxy covering and enzymes that break down pesticides. In fact, the pests are evolving faster than the chemicals can be developed, and most pesticides now struggle to kill an adult insect. Even the leaves of pest-resistant cotton are now dotted with holes where insects have attacked.

Cotton starts to blossom in the middle of August, and only then does the spraying stop. During the yearly harvest, one mu of land will yield between 250 kilograms and 300 kilograms of cotton on average; the costs of this single mu of land will reach 230 yuan (US$31) for fertiliser; 34 yuan (US$5) for agricultural membrane; 300 yuan (US$40) for chemicals; 70 yuan (US$9) for genetically-engineered seeds; and 100 yuan (US$13) to prepare the land. This results in a profit per mu of between 516 yuan (US$69) and 1,066 yuan (US$142) annually.

There are serious environmental consequences from this constant pesticide use. Water is taken from irrigation wells to dilute the chemicals, and some of the chemicals inevitably end up in the groundwater, threatening the health of local residents. In the course of our investigation, we saw numerous chemical containers left lying around a well. The plastic membrane that is used to cover the ground will be picked up and left between fields or burnt by more conscientious farmers, but many will leave it in the fields, eventually leaving the earth unsuitable for planting.

By contrast, Jin Anlei, a farmer in north China’s Hebei province, successfully developed a method of organic cotton farming. Jin uses sparrows to control pests, and steadfastly refuses to use fertiliser, pesticides or genetically-engineered crops. After seven years, his fields are rich and fertile, with large populations of crickets and earthworms. His bumper harvest in 2004 became famous at a time when other cotton farmers were suffering disastrous yields. Cotton experts from the China Academy of Agricultural Sciences made a special trip to visit his farm and were left speechless by what he had achieved.

Cotton is an important resource for clothing manufacture, and cottonseed oil has industrial uses. But do we have to pollute our environment for the sake of our clothes? Even genetically-engineered cotton requires huge quantities of chemical assistance. In any case, our long-term goal has to be protecting the environment and using our land sustainably.


Caihong Li is an MA student at Shandong Agricultural University; she won the Shandong Outstanding Graduate Award in 2007.

Jiang Gaoming is a professor at the Chinese Academy of Sciences’ Institute of Botany. He is also vice secretary-general of the UNESCO China-MAB (Man and the Biosphere) Committee and a member of the UNESCO MAB Urban Group.