RICE

Agricultural Uses

Rice (Oryza sativa) is probably the single most consumed food grain in the world. It has been in existence for the last 7000 years. Rice, an annual, is multi-stalked plant which grows to around a meter. The grains, borne by a panicle, are surrounded by bracts. Air columns in the stalk enable the diffusion of air through the stem down to the roots. The process of threshing and winnowing, followed by milling and polishing, converts the harvest into the marketable product that people commonly consume.
Since rice is the native of South-East Asia, it is best suited to a watery ecosystem and is mostly grown in flooded fields. Rice plants are able to resist decay even while they remain submerged for long periods. This happens by the help of the stems that are both elongated and perforated, helping the plants to photosynthesize and transport oxygen to the roots.
Over thousands of years of its existence, rice has adapted itself to survive different situations, like drought, floods, nutrient stress, etc. Rice is categorized according to the environment in which it grows. Thus, rice is grown in rainfed lowland, deepwater, tidal wetland, rainfed upland and irrigated land areas. Upland rice is the rice cultivated on lands without ponding
Rice is grown on 155 million hectares of land across 100 countries. Consumption of rice increases by an average of 2 % every year. Asia produces 92 % of the total rice, accounting for 90% of the harvested area. However, there is still a shortage of the grain in the world. While Australia has achieved the highest rice yield (10 tons per hectare). Asia manages only 3.9 tons per hectare. One of the reasons is that in Asia, there are about 250 million tiny land holdings dedicated to rice, making large scale agricultural practices difficult to adopt.
Rice is a good source of thiamine and niacin (both Vitamin B). It also provides iron, phosphorus and magnesium. It has higher levels of amino acid and lysine compared to other cereal grains.
Rice is also categorized on the basis of the nature and treatment of the grain, that is, size, variety and processing. Accordingly, there is long grain rice, medium grain rice, short grain rice (according to size) Arborio, jasmine, black rice, fermented red rice, parboiled rice, aromatic rice, glutinous rice, etc. (according to variety) and enriched rice, converted rice, instant white rice, etc. (based on processing methods). The nutrient value decreases when processes like mechanized milling and polishing are used. The unprocessed rice is called brown rice (the dehulled whole grain) which is more nutritious compared to white rice which is refined and processed.