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Sugarcane Planting and Harvesting

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Agricultural Processes
Sugarcane
Sugarcane
is a tall perennial grass that grows between seven and 16 feet (2 and 5 m). It has been around for at least 2,200 years and was reaped and harvested initially in southeastern Asia for chewing. Sugarcane harvesting is a complex process that involves careful cutting and handling procedures to maintain high sugar content and cane quality.

Sugarcane harvesting is a staple industry in many countries, including South Africa, as well as in Brazil, China, India, Malaysia, Hispaniola, and the United States. Sugar mills in Louisiana are among some of the most popular in the U.S., contributing billions of dollars towards the economy.

Harvesting methods include the most primitive and the most modernized. In developing nations, and even in some sugarcane mills that see more advantages to the manual method, little or no machinery is used for the labor-intensive process. Other countries and more prosperous mills tend to use a variety of harvesting equipment such as sugarcane harvesters, loading trailers, cranes, and bell grab loaders.

Contents

[edit] History

[edit] Sugarcane Origins

Sugarcane is believed to have originated in the South Pacific, before being brought by travelers during their conquests to Eastern and North Africa, the Middle East, India, China, Malaysia, and New Guinea. It has been cultivated for at least 2,200 years. Sightings of sugarcane were first recorded by the army of Alexander in India at around 326 B.C. By the time it reached Spain in 1150 A.D., 74,000 acres (30,000 ha) had been harvested. In fact, by this time, sugarcane had made its way to many, if not most, of the Caribbean countries, South America, Europe, the Orient, and Africa. Basically any tropical climate with the right soil conditions could grow sugarcane.

The first modern sugarcane mill was built in the Dominican Republic in 1516, and sugarcane harvesting methods would evolve throughout time. Four years later, sugarcanes were crushed by water-powered mills that grinded cane between two gigantic horizontal rollers. In the 1600s, sugar mills evolved with three vertical rollers in South America. This evolutionary method of crushing sugarcanes made its way to the U.S. in just a short period of time.

By the 1980s, sugarcane harvesting had proved to be such a successful, viable industry that 30.8 million tons of molasses were produced, with 5.2 million tons originating from Brazil.[1]

Sugarcane harvesting came to the U.S. approximately 200 years ago, with prosperous mills being developed in Louisiana. Sugarcane was first brought to Louisiana by Jesuit priests in 1751. Here, Etienne de Bore produced the first refined sugar from a sugarcane crop in 1795. His variety, named “Creole,” was one of many, including Otaheite, Louisiana Stripes, Louisiana Purple, and D74, to be developed in Louisiana.

The first years of sugarcane harvesting in Louisiana produced 300,000 tons of sugar per year and continued to boom until sugarcanes developed diseases, which resulted in a sharp decline in production.[2]

[edit] Traditional Reaping and Production of Sugarcane

Residents of Louisiana reaped sugarcanes the way they were taught by their European descendants, namely by digging furrows to plant canes in. Each row was about one yard wide and seeds were planted by hand at one-yard (0.9-m) intervals, sometimes as deep as six inches (15 cm). Anywhere between nine and 24 months later, the first crops of sugarcanes could be harvested, cutting the cane at the lower stem and leaving the rest to produce more crops. Crops could be cut and produced up to four times without having to be replanted.

Spanish settlers also brought with them the methods of producing sugar, which involved cutting the cane when it was fully ripe, releasing cane juice, and immediately subjecting it to crushing in sugar mills. The first mills were said to resemble round millstones that were set in the upright position and hauled by animals or pushed by humans. The first sugar mill production came from the Dominican Republic in 1516, using two horizontal rollers to crush the canes and extract juice.[3]

[edit]
Traditional Method of Sugarcane Harvesting
Traditional Harvesting

Early harvesting methods involved burning canes to remove leaves, weeds, and other trash. Harvesting also included, and still does in some fields, the cutting of stalks with machete-type knives, also known as cutlass. Similarly, canes were extracted by hand or cut with knives. This method was very labor-intensive and cutters were subjected to stooping in order to cut canes at the lower length desired for optimal sugarcane harvest.

Developed nations sought out methods that would rely less on physical labor. Sugarcane mills in Louisiana, for example, have been in existence for more than 200 years and have evolved from the basic harvesting method to the use of modern machinery.

[edit] Slavery and Sugarcanes in America

African slaves were brought to America from Europe and Africa. Many were employed in the first and subsequent sugarcane mills. Heavily involved in the process of planting and harvesting sugarcane crops, slaves had to endure the backbreaking work of planting rows upon rows of seeds. Traditionally, slaves, including men, women, and children, lined up and moved from row to row, planting seed stems by hand. It was expected that slaves should plant between 5,000 to 8,000 seeds in order to produce one acre (0.4 ha) of sugar. Planting seeds typically amounted to 10-hour days; harvesting took even longer.

Slaves who participated in traditional harvesting were required to cut the canes at the stem, remove any leaves and weeds, and stack the canes in bundles for loading onto donkey-drawn wagons or two-wheeled carts, where they would be transported to the sugar mill.

Slaves also ran the sugar mills and crushed stalks between giant rollers. Dozens of men were used to process sugar, boiling cane juice and breaking up sugar blocks into bits after crystallization had occurred.[4]

[edit] Process

Sugarcanes are planted in furrows at either horizontal or at 45-degree angles. It takes anywhere between 12,000 and 25,000 stems to plant 2.5 acres (1 ha) of land. After they are planted, they are covered with a light layer of soil. When they begin to grow and start sprouting, the furrow is turned inwards and the crops mature over the span of 9 to 24 months. Seeds can be planted by hand or by sugarcane equipment that cuts the canes into setts or billets and plants them in furrows.

Before canes are harvested, they are burned to remove any leaves or weeds that accompany them. A more modern method has developed where harvesters make their way up the rows to remove leaves and weeds.

In anywhere from eight to 12 months, a sugar stem, also known as a sett or seed piece, is cut from the sugarcane. It is more desirable to cut the stem from the upper third portion of the cane so that the maximum sugar content can be retained. This is also beneficial for the crop that remains planted, as it will continue to grow without any necessary replanting. The upper part of the cane is younger and less likely to deteriorate than the older portions of the cane. Some cutting methods require a cutlass, a machete-type implement that cuts at the lower slope of the cane. However, there is sugarcane harvesting equipment that can be driven up the rows, cutting and handling setts. Typically, a sugarcane harvester cuts the stem, compacting the soil in the meanwhile, and loads it into either a trailer or bin where it is transported to a sugar mill. Cranes are used to lift the bundles from the trailer or bin.

Harvesting normally takes place between June and December, when rainfall is at a minimum. When canes are harvested, the soil is left alone for a short period of time and then tilled and plowed by plows to allow moisture to access the seeds, which stimulates growth.

Inside the sugar mill, rollers are used to crush the canes, extracting juice comprising 10 to 20 percent sucrose. The juice then undergoes a process of removing impurities from the sugar and is crystallized in a centrifuge, where it is either processed into molasses or refined white sugar.[5]

[edit] Cutting/Harvesting Methods

There are several methods to choose from when cutting sugarcanes, each with their own set of advantages and disadvantages. The process of cutting canes must be done with care to ensure optimal quality of the cane’s sugar content. Some sugar mills in developing nations opt for basic cutting methods which involve little more than cutting stems with a cutlass, as is primarily done in South African countries. Other countries including the U.S. opt for more mechanized methods of harvesting and cutting, although these methods do not always yield the best results.

Utilizing machinery to harvest and cut sugarcanes sometimes means accepting losses to soil compaction and a decrease in the quality of the sugarcane. Dirt tends to associate itself more with machinery, affecting every process of sugar production, from the fields, to the grinding, to the final product. Below are several methods used for cutting and harvesting canes.

[edit] Basic Cutting Method

A method commonly used in South African fields, cane stems are cut with a can knife, while a second knife is sometimes used for topping. The more popular version is the cutlass, which eliminates the necessity of workers to stoop in order to cut the cane at the desired length. The cane is cut and the stems are bundled into a pile. This is known as the cut and bundle method.

A second basic cutting method is called the cutting length method. It involves workers cutting at a designated length for each row per day. The cane is then laid into windrows and collected by a bell grab loader, loaded into a box trailer, and taken to the site where it will be crushed and processed. This method can produce fairly high results, with 11.5 tons cut per worker per day, whereas the bundling system would only produce four tons per day. However, there are some drawbacks, --soil compaction due to the passing of the bell grab loader has less-than-desirable effects on the soil. This disadvantage is usually outweighed by the machine’s efficiency and reliability, not to mention the low maintenance costs associated with the bell grab machine.

[edit] Whole Stalk Harvesters

The whole stalk harvester, also known as soldier harvester, method was one of the most popular means of sugar harvesting in Louisiana until 1992, when the the “chopper harvester” surpassed it in popularity. The method essentially involves cutting the entire cane right to its base, removing the top, and placing the canes into heap rows. The rows of canes are then burned to remove trash and leaves and a bell grab loader loads them into a trailer to be transported to the sugar mill.

This method was not fully embraced as it included a number of disadvantages, including not being able to handle lodged canes and cane over 120 tons. This method did not work on slopes that inverted 10 percent or more. Cutters embraced the system because it was cheaper to put to work than the chopper system, it was easy to do, and less frequent losses were associated with it.

[edit] Chopper Harvesters

This method is similar to whole stalk harvesting in that the entire cane is cut, topped, and deposited into the machine, bottom-ended. The canes are cut into billets measuring 656 feet (200 m) in length by mesh rollers or rotor knives and then burnt. Dirt is removed from by an extraction mechanism. The billets travel up a conveyor, which sends them through a secondary extractor

The benefits of this are that choppers are combination equipment and no additional equipment is needed, and the strength required for physical labor is rated as minimal. Because the chopper is a combine machine, however, means that if one part fails, the entire harvesting process is delayed. Furthermore, high technical and operational skills are required to handle a machine of this magnitude. The quality of the cane is not as high because longer canes tend to deteriorate quicker and cane losses are more frequent.[6]

[edit]
Unique Facts

  • Molasses, dating back to early 19th century Germany, was used as fertilizer, starting around 1850. 
  • Molasses is distilled and fermented to produce many items: alcoholic distillate known as rum, which goes as far back as 2000 B.C., ethanol, vinegar, cosmetics, pharmaceuticals, cleaning solvents, and a product called bagasse used for making cardboard and paper.[7]
  • The average American consumes 100 pounds of sugar per year.

[edit] References

  1. Sharpe, Peter. Sugar Cane: Past and Present. Ethnobotanical Leaflets, 2008-09-29.
  2. History of Sugarcane in Louisiana. LSUAgCenter.com, 2008-09-29.
  3. History of Sugarcane in Louisiana. LSUAgCenter.com, 2008-09-29.
  4. West, Jean M. Sugar and Slavery: Molasses to Rum to Slaves. Slavery in America, 2008-09-29.
  5. Sharpe, Peter. Sugar Cane: Past and Present. Ethnobotanical Leaflets, 2008-09-29.
  6. Langton, M.I. Methods and Techniques of Sugarcane Harvesting, April 2004. (accessed: 2008-09-29)
  7. Sharpe, Peter. Sugar Cane: Past and Present. Ethnobotanical Leaflets, 2008-09-29.