About sugar cane
Sugar cane is a giant perennial grass belonging to the genus Saccharum. Being a tropical crop, it is grown in countries lying mainly in the tropical and subtropical regions of the world. They have stout, jointed, fibrous stalks (2.5 to 7.5 cm in diameter) that are rich in sugar and measure 2 to 6 meters tall. It is one of the most efficient photosynthesizers in the plant kingdom. It is a C-4 plant, able to convert up to 2 percent of incident solar energy into biomass. It synthesizes sugar which is stored in its stalk and can produce around 20 kg of biomass for each square meter exposed to the sun. Sugar cane is thus a source of sugar, molasses, a residual cane fibre (bagasse). Various co-products can be commercially produced from these basic products; ethanol including rum can be produced from sugar and molasses, bagasse can be used to produce paper, particle board and electricity amongst other co-products. Research is underway to hydrolyze bagasse leading to commercial production of ethanol and bio plastic from the hydrolyzed products.
All of the sugarcane species interbreed, and the major commercial cultivars are complex hybrids. The majority of the varieties cultivated in Mauritius are locally bred and includes M 3035/66, M 1557/70, M 1176/77, M 1246/84, M 1400/86 and M 703/89. Some varieties imported from Reunion island are R 570, R 573, R 575 and R 579. Mauritius produces around 4 500 000 tonnes of sugar cane annually.
What is sugar made from?
In the cane sugar industry, sugar is obtained from the juice extracted from the stalk found in a giant tropical grass called sugar cane.
Sugar cane plants look like bamboo stalks with elongated leaves. In the presence of sunlight, sugars are synthesized by the cane plant from water and atmospheric carbon dioxide and are stored in the cells of its stalk.
Requirements for sugar cane growth
Sugar cane, being a tropical plant, is normally grown in countries lying mainly within the tropics. It requires high temperature, ample supply of water and sunlight during the growth period. During the maturing period, it requires cooler temperature and drier conditions so that harvesting period is normally in winter. The synthesis of sucrose in the sugar cane plant starts with the photosynthesis with the help of chlorophyll in the cane leaves when hexoses are first formed and through the C4 cycle, sucrose are ultimately synthesized during the maturing period and stored in the cells of the cane stalk.
How is sugar cane cultivated?
Sugarcane is propagated from cuttings, rather than from seeds; although certain types still produce seeds, modern methods of stem cuttings have become the most common method of reproduction. Each cutting, also called “cane setts”, must contain at least one bud and is usually made up of about 40 centimetres of mature stalk. The cuttings are usually planted by hand but specialized agricultural equipment are being increasingly used. These “setts” are dropped into furrows, and then covered with soil after fertiliser application. The shoots come out of the “setts” within a few weeks and grow into fully mature plant in about 12 – 16 months.
Once planted, the cane is usually harvested every year after a period of 12 months. After each harvest, the cane sends up new stalks, called ratoons. The crop will normally be replanted after 6-8 ratoons. The harvesting operation is increasingly being mechanized, reaching about 34 % in 2007.
In Mauritius, the harvest season starts in June and ends in December.