Rice paddies

Abstract

Rice is the best-known wetland crop. Rice is also the most widely consumed staple food globally, a major part in the diet of more than half the world's population especially in Asia. In 2010, rice is also the grain with the second-highest worldwide production after maize. The importance of rice has been recognized for many centuries, as for example in India where it was once known as "dhanya" meaning "the sustainer of the human race". The edible portion of rice comprises seeds from two species of wetland grasses, Oryza sativa (Asian rice) and Oryza glaberrima (African rice). Asian rice is the dominant crop grown for subsistence and commercial purposes globally, with many cultivated strains across two principal subspecies: The sticky, short-grained variety (japonica or sinica); and the non-sticky, long-grained variety (indica). Paddy systems have persisted for over six millennia, their efficient productivity and retention of water, soil and nutrients leading to pervasive implementation across much of the tropical and subtropical world. Their central importance to communities means that they can be an organizing principle, also attracting spiritual and tourism importance. Greenhouse gas emissions from paddy fields may be significant, so improved stewardship systems are required to reduce associated emissions.