terrace

Yuanyang County (simplified Chinese: 元阳县; traditional Chinese: 元陽縣; pinyin: Yuányáng Xiàn; Hani: Yeiqyaq) is located in Honghe Prefecture, Yunnan province, China. It is well known for its spectacular rice-paddy terracing.

Yunnan (simplified Chinese: 云南; traditional Chinese: 雲南; pinyin: Yúnnán; IPA: [y̌nnǎn] ( listen)) is a province of the People's Republic of China, located in the far southwest of the country spanning approximately 394,000 square kilometers (152,000 sq mi) and with a population of 45.7 million (2009). The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.

Yunnan is situated in a mountainous area, with high elevations in the northwest and low elevations in the southeast. Most of the population lives in the eastern part of the province. In the west, the relative height from mountain peaks to river valleys can be as much as 3,000 m. Yunnan is rich in natural resources and has the largest diversity of plant life in China. Of the approximately 30,000 species of higher plants in China, Yunnan has perhaps 17,000 or more. Yunnan's reserves of aluminium, lead, zinc and tin are the largest in China, and there are also major reserves of copper and nickel. Yunnan has over 600 rivers and lakes, which provide an annual water supply of 222 billion cubic meters. Projected hydropower reserves stand at 103 GW, with an exploitable capacity of 90 GW.

A paddy field is a flooded parcel of arable land used for growing rice and other semiaquatic crops. Paddy fields are a typical feature of rice farming in east, south and southeast Asia. Paddies can be built into steep hillsides as terraces and adjacent to depressed or steeply sloped features such as rivers or marshes. They can require a great deal of labor and materials to create, and need large quantities of water for irrigation. Flooded paddies provide an ideal environment for rice cultivation and discourage the growth of many weeds.^{[citation needed]} The water buffalo is one of the most important working animals adapted for life in wetlands, and is used extensively in paddy field farming.

During the twentieth century, paddy field farming became the dominant form of growing rice.^{[citation needed]} Paddy field farming is practiced in Cambodia, Bangladesh, China, Taiwan, India, Indonesia, Japan, North Korea, South Korea, Malaysia, Myanmar, Nepal, Pakistan, the Philippines, Sri Lanka, Thailand, Vietnam, and Laos, as well as Piedmont in Italy, the Camargue in France, the Artibonite Valley in Haiti, and Sacramento Valley in California. Paddy fields are a major source of atmospheric methane and have been estimated to contribute in the range of 50 to 100 million tonnes of the gas per annum. Recent studies have shown that this can be significantly reduced while also boosting crop yield by draining the paddies to allow the soil to aerate to interrupt methane production.