Sugarcane is considered one of the most environmentally friendly crops because it requires minimal fertilizer and pesticides. It gets most of what it needs from the region’s rich, moist soil. Not only do our fields of sugarcane produce food, but they also provide shelter to many native plants and animals.
Sugarcane is perhaps best known as being the source of white sugar, but it is also a source of biofuel and syrup. The plant itself is actually a grass with a thick stem and feathered leaves and has been grown in some parts of the world as a food crop since at least 6000 B.C.
Sugarcane: Perennial Grass
Sugarcane (Saccharum officinarum), perennial grass of the family Poaceae, is primarily cultivated for its juice from which sugar is processed. Most of the world’s sugarcane is grown in subtropical and tropical areas. The plant is also grown for biofuel production, especially in Brazil, as the canes can be used directly to produce ethyl alcohol (ethanol).
The by-products from cane sugar processing, namely the straw and bagasse (cane fibres), can be used to produce cellulosic ethanol, a second-generation biofuel. Other sugarcane products include molasses, rum, and cachaça (Brazilian alcohol), and the plant itself can be used as a thatch and as livestock fodder. This article treats the cultivation of the sugarcane plant. For information on the processing of cane sugar and the history of its use, see sugar.
The sugarcane plant produces a number of stalks that reach 3 to 7 meters (10 to 24 feet) high and bear long sword-shaped leaves. The stalks are composed of many segments, and at each joint, there is a bud. When the cane becomes mature, a growing point at the upper end of the stalk develops into a slender arrow bearing a tassel of tiny flowers.
India is the second-largest producer of sugarcane, after Brazil. Saccharum is derived from the Greek word ‘Sakcharon,’ which means sugar especially sucrose. S. officinarum Linn, is a perennial grass, indigenous to tropical South Asia and Southeast Asia. It has a thick longitudinal stalk, which is generally three to five meters in height, approximately 5 cm in diameter, and is characterized by its sweet taste due to its high sucrose content. It is also known as chewing and noble cane. The sugarcane crop grows well in tropical and subtropical regions.
Sugarcane (Saccharum officinarum) is a tropical grass native to Asia where it has been grown for over 4,000 years. By 400 BC, methods for manufacturing sugar from sugarcane had been developed in India. Europeans were introduced to sugar during the Crusades. By the 11th century AD, sugar was being imported throughout Europe. Christopher Columbus likely brought the plant to the West Indies. Today, over 75 percent of the world’s sugar comes from sugarcane.
Sugarcane was one of the first “cash crops” of early colonial America. It grew plentifully in the southern states and was a major source of income for many plantations. High labor costs in the United States led to the industry’s rapid conversion to mechanical harvesting in the early 1990s.
The two centers of domestication for sugarcane are one for Saccharum officinarum by Papuans in New Guinea and another for Saccharum sinense by Austronesians in Taiwan and southern China. Papuans and Austronesians originally primarily used sugarcane as food for domesticated pigs. The spread of both S. officinarum and S. sinense is closely linked to the migrations of the Austronesian peoples. Saccharum barberi was only cultivated in India after the introduction of S. officinarum.
S. officinarum was first domesticated in New Guinea and the islands east of the Wallace Line by Papuans, where it is the modern center of diversity. Beginning around 6,000 BP, several strains were selectively bred from the native Saccharum robustum. From New Guinea, it spread westwards to maritime Southeast Asia after contact with Austronesians, where it hybridized with Saccharum spontaneum.
The second domestication center in mainland southern China and Taiwan, where S. sinense was a primary cultigen of the Austronesian peoples. Words for sugarcane exist in the Proto-Austronesian languages in Taiwan, reconstructed as *təbuS or **CebuS, which became *tebuh in Proto-Malayo-Polynesian. It was one of the original major crops of the Austronesian peoples from at least 5,500 BP. The introduction of the sweeter S. officinarum may have gradually replaced it throughout its cultivated range in maritime Southeast Asia.
From Island Southeast Asia, S. officinarum was spread eastward into Polynesia and Micronesia by Austronesian voyagers as a canoe plant by around 3,500 BP. It was also spread westward and northward by around 3,000 BP to China and India by Austronesian traders, where it further hybridized with S. sinense and S. barberi. From there, it spread further into western Eurasia and the Mediterranean.
The earliest known production of crystalline sugar began in northern India. The earliest evidence of sugar production comes from ancient Sanskrit and Pali texts. Around the eighth century, Muslim and Arab traders introduced sugar from medieval India to the other parts of the Abbasid Caliphate in the Mediterranean, Mesopotamia, Egypt, North Africa, and Andalusia.
By the 10th century, sources state that every village in Mesopotamia grew sugarcane. It was among the early crops brought to the Americas by the Spanish, mainly Andalusians, from their fields in the Canary Islands, and the Portuguese from their fields in the Madeira Islands. An article on sugarcane cultivation in Spain is included in Ibn al-‘Awwam’s 12th-century Book on Agriculture.
Christopher Columbus first brought sugarcane to the Caribbean during his second voyage to the Americas, initially to the island of Hispaniola (modern-day Haiti and the Dominican Republic). In colonial times, sugar formed one side of the triangle trade of New World raw materials, along with European manufactured goods, and African slaves. Sugar, often in the form of molasses, was shipped from the Caribbean to Europe or New England, where it was used to make rum.
The profits from the sale of sugar were then used to purchase manufactured goods, which were then shipped to West Africa, where they were bartered for slaves. The slaves were then brought back to the Caribbean to be sold to sugar planters. The profits from the sale of the slaves were then used to buy more sugar, which was shipped to Europe.
France found its sugarcane islands so valuable that it effectively traded its portion of Canada, famously dubbed “a few acres of snow”, to Britain for their return of Guadeloupe, Martinique, and St. Lucia at the end of the Seven Years’ War. The Dutch similarly kept Suriname, a sugar colony in South America, instead of seeking the return of the New Netherlands (New York).
Between 1863 and 1900, merchants and plantation owners in Queensland and New South Wales (now part of the Commonwealth of Australia) brought between 55,000 and 62,500 people from the South Pacific Islands to work on sugarcane plantations. An estimated one-third of these workers were coerced or kidnapped into slavery (known as blackbirding). Many others were paid very low wages. Between 1904 and 1908, most of the 10,000 remaining workers were deported in an effort to keep Australia racially homogeneous and protect white workers from cheap foreign labor.
Cultivation of Sugarcane
Sugarcane is propagated primarily by the planting of cuttings. The sections of the stalk of immature cane used for planting are known as seed cane, or cane sets, and have two or more buds (eyes), usually three. Seed cane is planted in well-worked fields. Mechanical planters that open the furrow, fertilize, drop the seed cane, and cover it with soil are widely used.
Seed cane is spaced 1.4 to 1.8 metres (4.5 to 6 feet) apart at densities 10,000 to 25,000 per hectare (4,000 to 10,000 per acre). Under favorable conditions, each bud germinates and produces a primary shoot. Root bands adjacent to each bud give rise to a large number of roots, and each young shoot develops its own root system. Tillering, or sprouting at the base of the plant, takes place, and each original seed cane develops into a number of growing canes, forming a stool. The plant crop is obtained from these stools.
Another method of cane propagation is rationing, in which, when the cane is harvested, a portion of the stalk is left underground to give rise to a succeeding growth of cane, the ratoon, or stubble crop. The ratooning process is usually repeated three times so that three economical crops are taken from one original planting. The yield of ratoon crops decreases after each cycle, and at the end of the last economical cycle all stumps are plowed out and the field is replanted.
Type of Soil
Sugarcane is grown in various kinds of soils, such as red volcanic soils and alluvial soils of rivers. The ideal soil is a mixture of sand, silt, and clay particles, with a measure of organic material. The land is plowed and left to weather for a time before subsoiling (stirring up the subsoil) is carried out. The crop demands a well-drained soil, and drains—on the surface, underground, or both—are provided according to the topographic conditions of the fields.
Moisture Requirement and Maturity
To attain good yields, sugarcane requires 2,000 to 2,300 mm (80 to 90 inches) of water during the growing period. When precipitation is deficient, irrigation, either by spraying or by applying water in furrows, can make up for the deficiency. The lowest temperature for good cane-plant growth is about 20 °C (68 °F). Continuous cooler temperature promotes the maturation of cane, as does withholding water. Harvesting and milling begin in the dry, relatively cool season of the year and last for five to six months.
In the proper conditions, sugarcane can reach heights of up to 13 feet (4 m). Larger isn’t always better, though, and soils that are too rich can produce larger canes with less sugar content. If allowed to grow long enough, feather-like plumes will sprout from the top of the cane. Usually, it is harvested before blooming; if the canes are cut back to the ground, they will regrow in the next cycle. Plants are described by the thickness of the cane; thin canes are known as just that, while the more desired, higher-producing thick canes are known as noble canes.
The time it takes sugarcane to reach maturity varies between six and 24 months, depending on where it is being grown and the type of plant. In commercial settings, canes are generally cut back and allowed to regrow until they cease to become productive. When this happens, a new crop is planted. Instead of using seeds that will yield plants quite different from the parent plants, sections are taken from an adult cane and planted to begin a process called vegetative propagation. New plants develop from sections of the old and are genetically the same as the original plants.
Fertilizers are applied to sugarcane from the beginning of planting through the whole growth cycle but not during the ripening period. Optimum amounts of fertilizers (nitrogen, phosphorus, and potassium) vary greatly with soil types, climatic conditions, and the kind and length of the growing cycle.
To secure a good crop, weeds in the cane fields must be attacked until the cane stools develop a good canopy, which checks weed growth. Weeding, still largely manual, is done with a hoe, though mechanical cane weeders with attached rakes have been developed. Chemical herbicides are widely used.
The mature cane is harvested by both manual and mechanical means. Some mechanical harvesters are able to sever and discard the tops of erect crops and cut cane stalks, which are delivered into a bin trailer for transport to the mill by tractor or light railway wagon.
The process of separating sugar from the sugarcane plant is accomplished through two steps: sugar mill crushing and sugar refinery extraction. Sugarcane is initially processed into raw sugar at mills near the cane fields. Because cane is bulky and relatively expensive to transport, it must be processed as soon as possible to minimize sugar deterioration. The raw sugar is then shipped to refineries to produce refined sugar. The final products of refining include powdered, granulated, and brown sugar, which is sugar that contains some molasses.
The number of sugarcane mills has steadily declined. In 2005, 21 cane sugar millers remained in business, with a combined milling capacity of 293,930 tons daily. With 13 mills, Louisiana had a daily milling capacity of 164,630 tons. Florida had five operating mills, Hawaii had two mills and Texas had one.
As of 2005, eight sugarcane refineries operated in the United States, dominated by the Domino Sugar Corporation and the Imperial Sugar Company. Dominos’ three plants are located in Louisiana, Maryland, and New York. Imperial operates plants in Georgia and in Louisiana. Florida’s sugarcane is refined by two companies: U.S. Sugar and Florida Crystals Corporation. The other refinery, located in California, is C&H, which has the largest capacity of any U.S. sugarcane refinery. It can process 3,400 tons of raw sugar each day. Four refineries have closed in the last decade. Thirty years ago, there were over twenty in operation.
Diseases and Pests of Sugarcane
The sugarcane plant is subject to many diseases. Sereh, a blackening, and degeneration of the fanlike tops, is caused by an East Indian virus. Mosaic, which causes mottling or spotting of foliage and sometimes curling, dwarfing, and narrowing of the leaves, is due to infection by any of several viruses.
Red rot (important in Indonesia and South Asia) is characterized by interrupted red and white patches within the cane along with a sour alcoholic odor when the cane is split open. Caused by the fungus Colletotrichum falcatum (Glomerella tucumanensis), red rot first attracts attention by yellowing and withering of the leaf, and eventually the entire plant dies.
Gumming disease (important in New South Wales, Australia) is characterized by gummosis, the pathological production of gummy exudates as a result of cell degeneration; it is caused by the bacterium Xanthomonas vasculorum.
Fiji disease, a virus disease first reported from the Fiji Islands, is characterized by elongated white to brown swellings on the underside of the leaves, followed by stunting and death.
Leaf scald is a vascular disease caused by the bacterium Xanthomonas albilineans, characterized by creamy or grayish streaking and later withering of the leaves.
Eyespot, characterized by yellowish oval lesions on leaves and stems, is a disease caused by the fungus Helminthosporium sacchari. Epidemics of these diseases have been checked by replacing the susceptible varieties of cane with varieties resistant to the disease.
Sugarcane is attacked and damaged by various insect pests that bore into and feed on the different parts of the plant. Control measures include biological control by parasites or predators, chemical control by insecticides, and the introduction of resistant cane varieties.
The moth borer, Diatraea saccharalis, which is widely distributed throughout cane-growing areas, is capable of causing extensive damage when out of control. The sugarcane leafhopper and the anomala grub yielded to biological control in Hawaii when other measures were unsuccessful. Various predator animals live on insects destructive to the sugarcane. For example, in Queensland, Australia, the bandicoot, an insectivorous marsupial, is a diligent destroyer of white grubs.
The insect pest responsible for some of the greatest crop losses is the grayback beetle in its larval stage. Effective grub control is obtained by applying the insecticide benzene hexachloride after the young cane plant has germinated and stooled, though this chemical has been banned in many countries. Sugarcane can be protected against wireworms by applying insecticides when cane sets are planted. Rats, which destroyed part of the stalk, are controlled by poisoning and trapping.
Sugarcane Breeding and Biotechnology
Sugarcane was originally cultivated by natives of the southern Pacific islands. Most present-day commercial canes are the offsprings or hybrids directly descended from the Cheribon cane (Saccharum officinarum), a Javan noble cane that was developed from a wild cane species, S. robustom. Noble canes, which represent the highest development of the species, are characterized by thick barrel-shaped internodes, or segments; large soft-rinded juicy stalks; and high sugar content.
The purpose of sugarcane breeding is to produce new hybrid varieties that will be immune, or resistant, to diseases and insect pests and will increase the production of sugar per unit area, yielding canes of higher sugar content and better fabrication qualities. Many of the original noble canes were susceptible to some serious diseases, but their hybridization with wild canes has improved their hardiness. For example, the wild cane S. spontaneum contains little sugar, and it is immune to most diseases; it has been used extensively by breeders to improve commercial varieties.
The first task of breeding is to obtain new cane seeds by sexually crossing selected parent varieties and then selecting seedlings from the new seeds. The crossing is effected by enclosing in a cloth lantern two flower tassels from two different cane varieties selected as a male and a female parent. The commercially superior varieties are not necessarily ideal parents. Many of the best varieties were bred from parents unsuitable for commercial use. The production of such cane seeds and seedlings by crossbreeding has been established in Java and Barbados since the 1880s.
A selected seedling is planted and tested in the fields and usually takes up to 10 years before being released as a new commercial variety.
Boosting the Sucrose Yield
Genetic manipulation is being conducted to increase the sucrose content of sugarcane. This work requires an understanding of the many interacting processes involved in the accumulation of sucrose in sugar-storing stems. Scientists have identified the key enzymes that set in motion these processes, which can be hastened or slowed down by genetic engineering towards the more efficient build-up of sucrose in stems.
In sugarcane, genetic modification is being carried out one step at a time to boost sucrose yield. For example, as a first step, South African scientists genetically knocked down a particular enzyme. This raised the amount of sucrose in young stems of the engineered sugarcane plants. Further tests in the field are being conducted. This and other recent developments1 clearly indicate the potential for substantial improvement in sucrose yield of sugarcane through precise modification of underlying processes.
Making Cellulosic Biofuel
Sucrose is widely used to make biofuel ethanol through fermentation. Ethanol provides an alternative to fossil fuels, which can reduce dependence on petroleum and curb greenhouse gas emissions. Sugarcane breeders have focused on sucrose yield to boost ethanol production. However, the increasing use of sucrose to produce ethanol instead of food has raised ethical and economic concerns. These concerns have emphasized the need to produce ethanol without compromising sucrose.
Biotechnology seeks to tap the cellulose in sugarcane leaves and bagasse (the leftover residue from crushed stalks) for ethanol production. The complex chemical structure of cellulose can be degraded by enzymes into simple sugars which can be fermented into ethanol. However, it is heavily guarded by a tough material called lignin that needs to be removed using a harsh pre-treatment procedure, which is very costly.
Biofactory for Niche Products
Sugarcane is the most efficient field crop in converting sunlight and water into biomass. For this reason, scientists find sugarcane as an ideal plant for the co-production of certain substances for medical and industrial applications. The genetic mechanisms within sugarcane cells can be tweaked to direct them to produce these substances, turning the whole plant into a biofactory. As proof, engineered sugarcane plants were shown to produce high-value chemicals like therapeutic proteins and natural precursors of biopolymers. This approach may turn out to be more efficient than current production methods.
Enhancing Crop Productivity
Transgenic technology may bring the productivity of sugarcane to an unprecedented level for the benefit of farmers and complement the aforementioned objectives. Genes taken from other organisms can be inserted into sugarcane to protect it from harsh environmental conditions and pests. The first transgenic sugarcane commercially released in Indonesia is a drought-tolerant variety9. This variety contains a bacterial gene responsible for the production of betaine, a compound that stabilizes the plant cells when there is a lack of water in the field.
The potential of sugarcane biofactory has drawn scientific and business interests, but its release for commercial use would be a huge regulatory challenge, especially if it is intended for open field cultivation. The risk of moving “unwanted” genes from plants designed for biomanufacturing to plants dedicated to food production is generally perceived as a drawback in biofactory approaches.
Thus, the commercial viability of a sugarcane biofactory will depend on the efficiency of risk containment relative to non-food plant biofactory systems like tobacco. Proponents will have to determine the efficiency and profitability of sugarcane biofactory on a case-to-case basis both from socio-economic and biosafety perspectives.
Value-added Sugarcane Products
Sucrose: The type of sugar produced by sugarcane is called sucrose. It is used as a sweetening agent for foods and in the manufacture of cakes, candies, preservatives, soft drinks, alcohol, and numerous other foods.
Blackstrap Molasses: This thick, dark liquid remains when the sugar has been removed from the boiled cane juice. It is used primarily as animal feed but can also be sold as syrup, to flavor rum and other foods, or as an additive for ethyl alcohol.
Bagasse (baa gas): After the juice has been extracted from the sugarcane stalk, this plant material remains. While generally burned as fuel for the mills, it could be used as a feedstock for ethanol production.
Ethanol: The increased demand for ethanol has generated interest in using U.S. sugarcane as a feedstock for producing fuel. Sugarcane, which produces a large amount of biomass per acre in the form of bagasse and cane stalks and leaves, would be a viable feedstock for the cellulosic conversion of biomass into ethanol. Instead of having to first convert the sugarcane to sugar juice, ethanol could be produced by processing the entire plant.
Electricity: In the United States, the Clewiston Sugar Factory in Clewiston, Florida, is powered by bagasse. In Brazil, sugar and ethanol plants produce electricity by burning bagasse and cane straw in boilers to produce steam that generates power. Currently, the plants generate about 1,800 megawatts in surplus electricity or about 3 percent of the country’s overall needs. According to UNICA (the Brazilian Sugarcane Industry Association), the sugarcane industry could generate an average of 15,000 megawatts by 2020, or enough to supply up to 15 percent of Brazil’s total electricity needs.
Uses of Sugarcane
In most countries where sugarcane is cultivated, several foods and popular dishes are derived directly from it, such as:
- Raw sugarcane: chewed to extract the juice.
- Sayur nganten: an Indonesian soup made with the stem of trubuk (Saccharum edule), a type of sugarcane
- Sugarcane juice: a combination of fresh juice, extracted by hand or small mills, with a touch of lemon and ice to make a popular drink, known variously as air tebu, usacha rass, guarab, guarapa, guarapo, papelón, aseer asab, ganna sharbat, mosto, caldo de cana, or nước miá.
- Syrup: a traditional sweetener in soft drinks, now largely supplanted in the US by high fructose corn syrup, which is less expensive because of corn subsidies and sugar tariffs.
- Molasses: used as a sweetener and a syrup accompanying other foods, such as cheese or cookies.
- Jaggery: a solidified molasses, known as gur, gud, or gul in South Asia, is traditionally produced by evaporating juice to make a thick sludge, and then cooling and molding it in buckets. Modern production partially freeze dries the juice to reduce caramelization and lighten its color. It is used as a sweetener in cooking traditional entrees, sweets, and desserts.
- Falernum: a sweet, and slightly alcoholic drink made from sugarcane juice.
- Cachaça: the most popular distilled alcoholic beverage in Brazil; it is a liquor made of the distillation of sugarcane juice.
- Rum is a liquor made from sugarcane products, typically molasses, but sometimes also cane juice. It is most commonly produced in the Caribbean and environs.
- Basi is a fermented alcoholic beverage made from sugarcane juice produced in the Philippines and Guyana.
- Panela, solid pieces of sucrose and fructose obtained from the boiling and evaporation of sugarcane juice, is a food staple in Colombia and other countries in South and Central America.
- Rapadura is a sweet flour that is one of the simplest refinings of sugarcane juice, common in Latin American countries such as Brazil, Argentina, and Venezuela (where it is known as papelón) and the Caribbean.
- Rock candy: crystallized cane juice.
Facts About Cash Crop
- Sugarcane is an important industrial crop that accounts for about 7% of the total agricultural output of the country; it is grown in almost all states.
- It provides the raw material for the second largest agro-based industry after textiles.
- India is the second-largest producer of sugar after Brazil. About 50 million skilled and semi-skilled workers, mostly from rural areas, are engaged in the sugar processing sector in India.
- In the world, sugarcane is grown in more than 120 countries, both in the tropics and the subtropics.
- About 63% area and 64% of production are confined to three countries: Brazil, India, and China.
- Asian countries account for about 34% of the sugar production and 41% of the consumption.
- Sugarcane is a water-intensive crop. It requires, on average, 30-40 irrigations.
- Inter-cropping of pulses, oilseeds, cereals, and vegetables with sugarcane needs to be promoted.
Source: 1. Britannica, All Things Nature, US Sugar, Ag Marketing Resource Center, Tribune India, wikipedia, International Service for the Acquisition of Agri-biotech Applications.
2. Singh, A., Lal, U. R., Mukhtar, H. M., Singh, P. S., Shah, G., & Dhawan, R. K. (2015). Phytochemical profile of sugarcane and its potential health aspects. Pharmacognosy reviews, 9(17), 45–54. https://doi.org/10.4103/0973-7847.156340