Xu Lai, chief editor of Guokr, or Nutshell, a popular social networking website for scientists.

Why do we need GM food? Well, take protein for example; the demand for protein is growing, but we don't have an endless supply of soybeans, which are a major source of forage. With regard to protein from animals, the meat, milk and eggs that humans consume require a huge amount of forage to feed all the pigs, chickens and cows.

The protein conversion rate in animals is very low, but chickens have the highest. If a chicken eats 0.9 kg of feed, it can produce 0.5 kg of meat, but a cow needs to consume 5 kg of feed to produce 0.5 kg of meat. As economic conditions have improved, the amount of animal protein in our diet has risen.

The second problem is soybean output. In China, it's more profitable to plant corn than soybeans. The yield rate of corn is higher than that of soybeans. Planting corn results in higher agricultural subsidies because of the high yield. Thus, soybeans and corn are in a competitive relationship. Farmers in the city suburbs prefer to plant fruit and vegetables, and that's why China needs to import several million metric tons of GM soybeans every year. Import volumes are rising, indicating that the amount of arable land in China is becoming insufficient.

- Zhang Lei

(China Daily USA 10/23/2013 page7)