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Monday, March 28, 2011

RICE

RICE (Oryza sativa) is an annual swamp plant that has been cultivated for several thousands years as the principals cereals of South East Asia from Japan to India. This crop was grown by peasant and subsistence farmers who use traditional methods that not changed since the rice cultivation began many decade ago. I would like to write about rice based on my reading on few books and my own field experience in agriculture sector for almost 30 years. Rice production in most developed country mostly mechanised and high productivity compare to many less developed nation such as in USA, Australia and Japan. China, India, Indonesia, Bangladesh and Thailand among those country produce huge amount of rice for domestic and export market. Rice or scientifically known as Oryza sativa have been domesticated since 4,000 years ago in India from a wild species of Oryza perennis and Oryza glaberrima. In Africa the species domesticated are Oryza barthii originated of the Niger River. The selection and research of rice in many thousands years suits the local taste and the local environments under which they are grown.


Now only three sub-species sre recognised in rice growing activity that was Oryza sativa subsp. indica, Oryza sativa subsp. japonica and Oryza sativa subsp. javanica. I remember that the rice subspecies will produce special characteristic based on the taste and demand of local people. The first Oryza sativa subspecies 'indica' or 'Indica Rice' which consists a large group of reproductively photosensitive, short day cultivars of the tropical monsoon region of South East Asia grown in the warm , humid regions where the water is plentiful. The soil normally infertile and poor or low fertility which are flooded as the crops grows. They tend to be tall, with long straw which lodges easily if growth and grain yield are increased by the use of nitrogen fertilizers. Compare to 'japonica' the rice grain size are 'SMALL'. The grain size normally longer than 9 mm and when they are overcooked remain separate and do not became 'mushy'.


The Oryza sativa subspecies japonica or common name as 'japonica rice' are both sensitive and insensitive to photoperiod according to the cultivar. This rice popular in Japan, Korea and China and elsewhere outside the tropic such as in Lousiana USA, Australia and Italy. It tends to have shorter straw than 'indica' types and responds better to the application of fertilizer to give large yields without lodging. Typically the japonica grains are short (about 7 mm long) and do not resist overcooking but to become 'mushy' and stick together. The third rice was Oryza sativa subspecies javanica or 'javanica rice' which are insensitive to photoperiod but with has a long vegetative phase. It is well adapted to the equatorial climate of Java and Indonesia and known little grown elsewhere. Cultivars of this three sub-species are commonly referred to to one of three classes according to the conditions under which they are grown and to which they are best adapted.


SWAMP RICE or WET PADDY accounts for by the greatest part of the worlds rice production. It is grown in the fields surrounded by bunds or leaves built to retain flood water and to control its flow. In most part of Asia where the population is very dense the field are even built on steep hillsides (see photo) to form terraces such as in Indonesia and other countries. The land is levelled and cultivated and seed are broadcast by hand with certain amount of fertilizer application. Where thee was not enough water supply during dry period, the seed was sown in the nursery and transplanted 5-7 weeks when they are 20-30 cm tall. The rice field were 'puddled' by working it during it is wet before transplanting. In many area there are more than one cycle of rice planting in a year.

Floating Rice are cultivars adapted to conditions where flood waters are uncontrolled and become very deep (up to 5 meter). from my visits to Myanmar and Bangladesh in 2009 it was few floating rice varieties selected for this kind of situation in both countries. They used boats ans sampan to harvest the yield during certain period of harvesting season. the rice has internode able to elongate quickly as the flood rises and the leaves and inflorences float on the water surface. The yield are not very high as compared to the swamp rice.


UPLAND RICE or 'Dry paddy' or in Malaysia called 'PADI HUMA or PADI BUKIT' is grown like other dry land cereal crop. It depend purely on rain irrigation though it is sensitive to dry weather. From my observation in Sarawak of East Malaysia the dry paddy produce about 1.5 - 2.5 kg/ha considered a very low productivity among all. This dry paddy was grown by subsistence farmers around longhouse once a year with a very minimal fertilizer application and almost no chemical used. This rice can be considered as 'organic rice' and good for health.

Another important classification of rice cultivars depends upon the kinds of starch stored in the endosperm. The starch of 'glutinous' or soft rices is mostly amylopectine; the broken surface of the grains has a chalky appearance and they are said to have soft, opaque fracture. Even they are overcooked soft rices become gelatinous and sticky and on subsequent cooling set to a gel. On the other hand starch on the endosperm of hard rices is about one-quarters amylos and three-quarters amylopectin. The grains have a vitreous (glass-like) fracture and do not become sticky when overcooked. Hard rice are grown more extensively and more important in world trade than the soft rice.

I hope this article provide all readers a knowledge of rice crop. The current rice growing hectarage in Malaysia about 622,000 hectare able to supply 75% of domestic requirements. There are 8 rice growing bowl in Malaysia located in Kedah, Perak, kelantan, Selangor and few others with an avereage production of 4-5 metric ton per hectare. The highest production of rice recorded in Sekinchan area in Selangor about 8-10 metric ton per hectare. Rice is a staple food for Malaysian.


By
M Anem
Kedah
Malaysia

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