Considering that only about 10 percent of China's land is arable, how has China managed to become the world's leading producer of many farm products?

China has become a world leader in production of farm products including rice, wheat, potatoes, sorghum, peanuts, tea millet, barley, cotton, oilseed and soybeans. Initially going back eons, first the use of cast iron tools and beasts of burden were introduced in agriculture. Now, while communes have beendisbanded, and individual farming has been restored, there are quotas for the individual farmers and also some state farms. In modern times, mechanization has been promoted and state sponsored projects like the Three Gorges Dam has provided significant irrigation.