Growing sugarcane

Cane sugar is a raw material we use in the manufacture of our range of pure syrups and crystalline sugars. The primary source of sucrose, sugarcane is milled or refined into multiple types of sugar products, such as demerara sugar and refined white granulated sugar. Sugarcane accounts for 80% of the world’s sugar production, compared to 20% for beet sugar.

In this blog, we explore how to plant, grow, maintain and harvest sugarcane and why this crop is prized for use in a diverse range of sectors.

Sugarcane is a type of perennial grass that is grown in tropical and subtropical parts of the world. As a plant, it requires a warm, temperate climate all year round and plenty of sun and water, either through rainfall or irrigation. Sugarcane is averse to frost or freezing temperatures, and especially cold conditions will kill the cane.

Cultivation originated in the South Pacific region, where the seasons swing between being dry and wet.

At full maturity, sugarcane has fibrous stems that can reach a height of 4m to 6m and a diameter of around 4cm. The plant will also have long, slender leaves. Juice is extracted from the sucrose-concentrated stem which is then used to make sugar.

As sugarcane is a C4 plant, one of three kinds of photosynthetic processes relating to carbon fixation in plants, it is effective in its ability to convert up to 1% of the solar energy it receives into the biomass of the plant itself. All plants capture the sun’s energy through their chlorophyll and use it to produce sugars, with sugar beet and sugarcane producing and storing enough sugar that they can be grown specifically for that sugar.

There are different techniques for planting sugarcane: flat, furrow and trench planting. The technique chosen will depend on the region and specific conditions. For example, trench planting is ideal in areas with strong winds as the plant is more protected.

Sugarcane can be propagated from seeds or cuttings. However, cane seeds are generally too small to plant directly in the field, and some varieties of sugarcane lack seeds entirely. For commercial cultivation it is more efficient to use cuttings. Harvested, mature stalks are cut into 20-inch segment ratoons. These are placed in furrows in the field by a mechanical planter and covered with soil. The best type of soil for sugarcane growing is a well-drained clay soil that is properly irrigated and free of weeds.

There are different stages in the sugarcane growing lifecycle. The germination stage comes first, followed by the tillering phase about three weeks later, where sprouts appear. Depending on the variety, the tillering stage can last between four to eight months. After this, internodes develop, and the stems grow longer and gain structural strength.

Then, about 12 to 16 months after planting, the sugarcane will have fully ripened and matured and be ready to harvest. The time it takes for sugarcane to be ready for harvesting varies. In hotter climates, it can be harvested 12 months after planting or even a little earlier, while in cooler regions it can take a little more than 12 months.

Once the cuttings have been planted, farmers will already have a programme in place for managing weeds and pests, and for disease prevention. In some countries, farmers may be limited on what pesticides they can use on the crop or what is available to control pests and prevent disease due to concerns around soil degradation and environmental pollution. 

There are many pests and weeds that threaten sugarcane, including downy mildew, leaf scorch, white leaf disease and mosaic viruses. Root grubs and termites are common and damaging pests for sugarcane, but more environmentally sustainable management methods are available for growing organic sugarcane. For example, insects such as ladybirds can act as a biodiverse treatment option. However, insecticides such as phorate are used at scale because they are cost effective.

Fertilisers may be used to stimulate plant growth and increase crop productivity. For farmers, effective weed, land and crop management are essential to ensure healthy growth and higher yields.

Harvesting must be an efficient process, as once the stems are cut the sugar content will decrease and degrade rapidly. When the stems are cut, the bottom is left to allow the plant to regrow. Mechanical harvesters are used to make the process more efficient. The tradition of cutting by hand is reserved for inaccessible smallholding fields that the harvester can’t reach.

During cutting, the leafy top of the sugarcane will be cut. Increasingly, this is left on the field as organic fertiliser. The separated stems are then cut into short pieces, called billets.

Unlike sugar beet’s single harvest, it is possible to harvest efficiently several sugarcane crops from a single planting. Following cutting, a sugarcane plant will grow new stalks called ratoons. With each successive harvest usually resulting in a smaller yield than the one before it, most sugarcane farmers will opt for a total of four harvests.

This amount varies depending on climate, demand and availability of fertile ground. On Réunion Island, for example, where sugarcane agriculture is incredibly important to the local economy, farmers will harvest sugarcane repeatedly over several years before replanting. Once cut, the cane billets are loaded into a trailer and transported to a sugar mill. This is often done using road transport or tramways for greater efficiency at scale. On entering the mill, each batch will be weighed and analysed before the stems, which carry the sucrose, are crushed to extract the juice.

Globally, sugarcane is an important crop, and the industry has long been interested in alternate uses for it beyond sugar products. With major businesses involved in its production seeking to push toward both ethical and sustainable farming practices, the potential for the crop to be used more diversely has been embraced across the world.

In Brazil, the world’s largest producer of sugarcane, sugarcane is partly grown for ethanol production. Sugarcane ethanol, which is a sustainable renewable fuel, forms an important part of Brazil’s biofuel industry and helps power 40% of cars and light vehicles on the country’s roads. 

It is bagasse that is used as a biofuel for heat, electricity and energy production. Bagasse is the fibrous material that is left after crushing sugarcane stalks and extracting the juice. Bagasse is also burnt in boilers to power sugar mills, and any excess electricity produced is supplied to the local electrical grid.

Sugarcane’s uses, however, extend beyond biofuels to the cosmetics industry, for example. As an ingredient in skin care products like face masks, sugarcane extract can act as a humectant to hydrate and brighten the skin. Alternatively, after processing, the stalks and leaves of the sugarcane are often used as feed for livestock, or used to make paper, cardboard, pens, matting or textiles.

Sugarcane is central to our industry, but it is becoming increasingly important to other industries. At Ragus, we manufacture a range of speciality pure syrups and crystalline sugars from sugarcane. To learn more, contact our Customer Services Team. For more sugar news and updates, browse SUGARTALK and follow Ragus on LinkedIn.