"Hundreds of millions of farmers make a living from rice. The health of each one of them is at risk from pesticide use," said Lu Ping, a researcher at China Agricultural University.

Last year, Lu and her team spent 40 days in a village in Sichuan, a major rice-growing province. They discovered that, from a population of 2,000, three farmers had died from diseases related to long-term exposure to pesticides in the last three years. "Most rice farmers underestimate just how toxic these chemicals and sprays are. They rarely wear any of the necessary protection, such as mask and gloves," she said.

One man was killed when he accidentally swallowed pesticide while trying to suck an obstruction out of a spray pipe, she recalled. "Another villager showered his cow with pesticide to kill lice but instead killed the cow. He then ate the dead animal. He survived but he had no idea he could have poisoned himself."

Sun Jing, director of the Pesticide Eco-alternative Center in Yunnan province, conducted similar studies since 2007. Her team has interviewed hundreds of farmers and found 20 percent regularly suffered dizziness or nose bleeds after using agricultural chemicals. "There's no doubt these chemicals, especially pesticides and herbicides, harm farmers' health," she said. "Reducing the use of pesticide and promoting alternative forms of pest control will be the future of farming."

A scientist holds GM rice in his left hand and natural Heilongjiang rice in his right. [China Daily]

A GM rice crop that repels pests without the need for chemical sprays would be many people's choice for an alternative, said Sun. However, there are still serious concerns over the safety of GM food, with debate continuing to rage over whether it is potentially dangerous to consumers.

"Rice is eaten by almost every single person in China, so people are particularly concerned about GM rice," said Xue Dayuan, chief biodiversity scientist at the Nanjing Institute of Environmental Sciences under the Ministry of Environmental Protection. "Risks also come from the potential genetic pollution."

Genes from GM rice could contaminate other species, potentially causing uncontrolled hybridization, which could put pure wild varieties at serious risk of extinction, he said. "We need precise regulation on GM crops before commercialization. I'm worried that we haven't set up an effective system to regulate the research and production of GM food."

Although agriculture officials are yet to approve the commercial cultivation of GM rice or the importation of GM grain, a report released by Greenpeace China on March 15 said GM rice is already on sale at Wal-Mart and Zhongbai stores in Hunan province.

The provincial government denied the claims, saying that no pest-resistant GM ingredients had been found in any of the 32 brands of rice being sold at the supermarkets. "Samples were taken from the Wal-Mart outlet in the capital Changsha, and several other stores and mills, but no GM ingredients were found after careful analysis by professional testing institutions," the authority said in a statement.

For retired farmer Mei, the biggest question is whether the genes that kill insects are also potentially hazardous to humans. "It seems like they're integrating pesticide into the rice, so doesn't that make it toxic?" he said. "Maybe the toxic element hasn't been found yet. I will only believe it is 100 percent safe after people have eaten it for several generations."

When Chinese farmers began planting GM soybeans imported from the United States and yields went from 1,500 kg per hectare to 4,500 kg, Mei was initially amazed by this "magic" crop. "But nothing is perfect. GM technology seems too good to be true," he said. "The newspapers told us pesticides were perfectly safe at the very beginning but now everybody knows they aren't. Who knows what is going to happen with GM rice after five or 10 years."

Using pesticides and herbicides, Mei's farm grew about 150,000 kg of grain and generated about 375,000 yuan ($55,000) a year, a fair income in China's countryside.

"I believe Chinese farmers can provide enough grain for all of us. Why should we take the risk of using uncertain technology?" he said.