Rice is a cereal foodstuff which forms an important part of the diet of many people worldwide.
Domesticated rice comprises two species of food crops in the Poaceae (“true grass”) family, Oryza sativa and Oryza glaberrima. These plants are native to tropical and subtropical southern Asia and southeastern Africa.
The name wild rice is usually used for species of the different but related genus Zizania, both wild and domesticated, although the term may be used for primitive or uncultivated varieties of Oryza.
Rice is grown as a monocarpic annual plant, although in tropical areas it can survive as a perennial and can produce a ratoon crop and survive for up to 20 years. Rice can grow to 1–1.8 m tall, occasionally more depending on the variety and soil fertility. The grass has long, slender leaves 50–100 cm long and 2–2.5 cm broad. The small wind-pollinated flowers are produced in a branched arching to pendulous inflorescence 30–50 cm long. The edible seed is a grain (caryopsis) 5–12 mm long and 2–3 mm thick.
Rice is a staple for a large part of the world’s human population, especially in tropical Latin America, and East, South and Southeast Asia, making it the second-most consumed cereal grain. Rice provides more than one fifth of the calories consumed worldwide by humans.In early 2008, some governments and retailers began rationing supplies of the grain due to fears of a global rice shortage.
Rice cultivation is well-suited to countries and regions with low labor costs and high rainfall, as it is very labor-intensive to cultivate and requires plenty of water for cultivation. On the other hand, mechanized cultivation is extremely oil-intensive, more than other food products with the exception of beef and dairy products. Rice can be grown practically anywhere, even on a steep hill or mountain. Although its species are native to South Asia and certain parts of Africa, centuries of trade and exportation have made it commonplace in many cultures.
The traditional method for cultivating rice is flooding the fields with or after setting the young seedlings. This simple method requires sound planning and servicing of the water damming and channeling, but reduces the growth of less robust weed and pest plants that have no submerged growth state, and deters vermin. While with rice growing and cultivation the flooding is not mandatory, all other methods of irrigation require higher effort in weed and pest control during growth periods and a different approach for fertilizing the soil.