Rice is a staple food 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
Rice has fed more people over a longer period of time than any other crop. As far back as 2500 B.C. rice has been documented in the history books as a source of food and for tradition as well.
Rice could be taken to many parts of the world due to its versatility. It is able to grow in the desert conditions of Saudi Arabia, in the wetland deltas of Southeast Asia in the flooded rice plains which we are most familiar with.
Two species have emerged as our most popular cultivated rice. Oryza sativa and Oryza glaberrima, of these two species the more widely produced is O. sativa. From an early history in the Asian areas rice has spread and is now grown on all continents except Antarctica.
Being able to grow in this wide spectrum of climates is the reason rice is one of the most widely eaten foods of the world.
Rice cultivation is well suited to countries and regions with low labour costs and high rainfall, as it is very labour-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 whilst, or after, setting the young seedlings. This simple method requires sound planning and servicing of the water damming and channelling, 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.