Rice is the seed of the grass species Oryza glaberrima (African rice) or Oryza sativa (Asian rice). As a cereal grain, it is the most widely consumed staple food for a large part of the world's human population, especially in Asia and Africa. It is the agricultural commodity with the third-highest worldwide production (rice, 741.5 million tonnes in 2014), after sugarcane (1.9 billion tonnes) and maize (1.0 billion tonnes).
Origin of rice domestication has been a subject of much debate among those who study crop history and anthropology - whether rice originated in India or China. Asian rice, Oryza sativa, is one of oldest crop species. It has tens of thousands of varieties and two major subspecies, japonica and indica. Archeologists focusing on East and Southeast Asia argue that rice farming began in south-central China along the Yangzte River and spread to Korea and Japan from there south and northeast. Archaeologists working in India argue that rice cultivation started in the valley of the Ganges River and Indus valley, by peoples unconnected to those of the Yangzte.
Rice is typically rinsed before cooking to remove excess starch. Rice produced in the US is usually fortified with vitamins and minerals, and rinsing will result in a loss of nutrients. Rice may be rinsed repeatedly until the rinse water is clear to improve the texture and taste.
A detailed analysis of nutrient content of rice suggests that the nutrition value of rice varies based on a number of factors. It depends on the strain of rice, such as white, brown, red, and black (or purple) varieties having different prevalence across world regions. It also depends on nutrient quality of the soil rice is grown in, whether and how the rice is polished or processed, the manner it is enriched, and how it is prepared before consumption.
By the late Neolithic (3500 to 2500 BC), population in the rice cultivating centers had increased rapidly, centered around the Qujialing-Shijiahe culture and the Liangzhu culture. There was also evidence of intensive rice cultivation in paddy fields as well as increasingly sophisticated material cultures in these two regions. The number of settlements among the Yangtze cultures and their sizes increased, leading some archeologists to characterize them as true states, with clearly advanced socio-political structures. However, it is unknown if they had centralized control.
However, rice (as well as dogs and pigs) did not survive the first Austronesian voyages into Micronesia due to the sheer distance of ocean they were crossing. These voyagers became the ancestors of the Lapita culture. By the time they migrated southwards to the Bismarck Archipelago, they had already lost the technology of rice farming, as well as pigs and dogs. However, knowledge of rice cultivation is still evident in the way they adapted the wetland agriculture techniques to taro cultivation. The Lapita culture in Bismarck reestablished trade connections with other Austronesian branches in Island Southeast Asia. They also came into contact with the non-Austronesian (Papuan) early agriculturists of New Guinea and introduced wetland farming techniques to them. In turn, they assimilated their range of indigenous cultivated fruits and tubers, as well as reacquiring domesticated dogs and pigs, before spreading further eastward to Island Melanesia and Polynesia.
Today, the majority of all rice produced comes from China, India, Indonesia, Bangladesh, Vietnam, Thailand, Myanmar, Pakistan, Philippines, Korea and Japan. Asian farmers still account for 87% of the world's total rice production. Because so much rice is produced in Bangladesh, it is also the staple food of the country.
The Ifugao people practice traditional farming spending most of their labor at their terraces and forest lands while occasionally tending to root crop cultivation. The Ifugaos have also been known to culture edible shells, fruit trees, and other vegetables which have been exhibited among Ifugaos for generations. The building of the rice terraces consists of blanketing walls with stones and earth which are designed to draw water from a main irrigation canal above the terrace clusters. Indigenous rice terracing technologies have been identified with the Ifugao's rice terraces such as their knowledge of water irrigation, stonework, earthwork and terrace maintenance. As their source of life and art, the rice terraces have sustained and shaped the lives of the community members.
One of the earliest known examples of companion planting is the growing of rice with Azolla, the mosquito fern, which covers the top of a fresh rice paddy's water, blocking out any competing plants, as well as fixing nitrogen from the atmosphere for the rice to use. The rice is planted when it is tall enough to poke out above the azolla. This method has been used for at least a thousand years.
In the United States, colonial South Carolina and Georgia grew and amassed great wealth from the slave labor obtained from the Senegambia area of West Africa and from coastal Sierra Leone. At the port of Charleston, through which 40% of all American slave imports passed, slaves from this region of Africa brought the highest prices due to their prior knowledge of rice culture, which was put to use on the many rice plantations around Georgetown, Charleston, and Savannah.