Candy bars, soft drinks and ice cream can be found in every corner shop around the world. But during most of human history, the crystals that make our food sweet were pretty hard to come by. For quite some time, sugar was even called “white gold” due to its rarity and promising profits. Although sugar is found in many plants, the only crops that contain it in high enough concentrations for an efficient harvest are sugar cane and sugar beet. Today, science and technology have greatly advanced the cultivation of these crops and made the global sugar trade more promising than ever before.
Most of the world’s sugar comes from sugar cane. The tall grass looks a lot like bamboo and can grow up to six meters high. It accounts for 70 to 80 percent of global sugar production and even leads the list of net agricultural production by weight: Almost two billion tons were harvested globally in 2013 – twice as much as was harvested in maize, the next most harvested crop. In other words, more than 20 percent of the world’s entire agricultural production is attributed to sugar cane. Around 700,000 tons are produced on Victor Campanelli’s land each year. “I am absolutely convinced that we can influence only around 20 percent of the sugarcane’s productivity. The rest certainly depends on the weather,” the farmer from São Paulo, Brazil says. And indeed, sunlight and lots of water are the main ingredients for good cane growth.
Crystals of Delight
As the green stalks grow, they take up water and minerals through their roots as well as carbon dioxide through their leaves. These building blocks are then combined into sugar through photosynthesis. “The sugar is actually only concentrated at the bottom of the cane stalks,” explains Campanelli. To get to the sugar reserves, the stalks are harvested manually or by machine 12 to 18 months after they are planted. They are then stripped and crushed. This results in a juice and a fibrous by-product known as ‘bagasse’. The juice is strained and then heated and mixed with lime to remove impurities. It is then transferred to evaporators to extract syrup consisting of sugar crystals. Lastly, the crystals are separated in a centrifuge. The bagasse that has been left over after the sugar was extracted can be burned and used to generate electricity that powers the whole sugar mill. But there’s also a new and growing reason the world is turning to sugar cane. Through fermentation, the sugar can also be turned into bioethanol. Thanks to this, the sugar cane market has the highest projected growth rate of any other major crop.
Natural solar power
But not only people appreciate the giant stalks. Today’s most important pest in Brazil is the root leafhopper. “On my farmland, the hardest pest to control is the sugarcane borer, a pretty voracious caterpillar,” remarks Campanelli. Weeds are another uninvited guest in tropical cane plantations, as they compete for nutrients and sunlight: “Over the past decade, sugar cane cultivation has changed 100 percent” says Campanelli. “We now have a mechanical harvest so we no longer need to burn the fields for the laborers’ safety.” On the other hand, Campanelli also reminisces about the time when sugar cane needed hardly any crop protection: “We used to harvest, fertilize and apply some herbicide to prepare the field for the next season.” Today, he complains of lower herbicide efficiency, the appearance of new pests and the necessity of more applications of insecticide and fungicide. But Campanelli also sees light at the end of the tunnel: “Precision agriculture is becoming key in sugar cane cultivation. With it we can raise the fertility of our soils, raise our productivity and use fertilizers and crop protection in a more rational and sustainable manner.”
With precision agriculture we can raise the fertility of our soils, raise our productivity and use fertilizers and crop protection in a more rational and sustainable manner.
In temperate climates, particularly in Western, Central and Eastern Europe, the United States, China and Japan, farmers face similar challenges. There, sugar is produced from sugar beets. Compared to sugar cane, the sugar beet is an invention of modern times. Today, over 100 million tons of sugar beet is grown annually in the European Union alone and one of its producers is Ludovic Franquet from Allibaudieres in France. “The leaves of the sugar beet plant are its ‘chemical laboratory’. They produce the sugar that is stored in its root,” he explains. In contrast to sugar cane – that is cultivated by propagating old stems – sugar beet can be sown as seeds. They grow quickly and can be harvested from September to December of the same year. “The more sun the sugar beets see in a season, the sweeter they are,” comments Franquet. And the better for him and his farmer colleagues: Their harvest is weighed and sampled to assess the sugar content and the sugar mill pays them accordingly. There, the beets are cut into thin strips and washed in a current of hot water. The resulting liquid is purified, filtered, concentrated, evaporated and then boiled under vacuum to trigger crystallization. Lastly, a centrifuge delivers the final product: white sugar.
Everything is Utilized
Farmer Franquet has cultivated the sweet root since 1968 and knows one of its main advantages: “It can be easily integrated into a crop rotation plan. I have a regular rotation of five different crops. Next to sugar beet, I cultivate wheat, barley, oilseed rape and also potatoes.” This rotation is of utmost importance to keep crop protection products, particularly herbicides, effective. And it has been a long challenge to find an agent that acts selectively against weeds without harming the extremely sensitive beet plant. But over the years, Bayer has been enhancing a product family that offers beet growers reliable and customized solutions. Thanks to innovative formulation concepts and consequent rotation efforts by the farmers, no resistances to the active ingredients have been observed.
In light of these helpful technologies and precision agriculture, both sugar crops have even more exciting times ahead of them. In Brazil, scientists are working on new varieties of sugar cane with drastically improved sugar content. And for sugar beets, Bayer is cooperating with other companies to develop varieties with improved herbicide tolerances. The efforts will certainly raise yields to meet the demand without having to extend the areas of cultivation – a clear win for more sustainability and a sweeter future.
It can be easily integrated into a crop rotation plan. I have a regular rotation of five different crops.
The Search for the Perfect Sugar Beet
What does the perfect sugar beet look like?
A good top makes the perfect beet: The leaf node should be in the center and have a diameter of no more than three centimeters. This way, we have minimal losses when slicing the top off at harvest. If the beet has sprouts on its sides, the topping and defoliating with minimal losses becomes more difficult.
Have there been changes in sugar beet cultivation in recent years?
Higher yields are the omnipresent motive. Within the past ten or fifteen years, the types of sugar beet that were bred primarily were those with dense leaves or beets with a greater weight. And climatic changes have proven to be quite useful. Sugar beets are benefitting from higher average summer temperatures that promote growth. Nevertheless, there are also disadvantages if yield is the only thing that matters: Due to the higher weight and sugar yield, the beets have become more fragile.
How can seed developers contribute to an effective harvest?
For the harvest, it is important how the beet has grown: The deeper in the ground it is, the deeper the machines have to dig up and the more furrowed the field becomes. The soil also sticks to the beet. If the beet’s head grows clearly above ground, collecting it becomes a lot easier. Cleaning is next: If the beet has cracks the soil clings to them and they become harder to clean. In addition, the beets break easily. A smooth, robust sugar beet, which grows directly under the surface is still an unmet challenge for breeders.
Does the sugar industry have an influence on farmers?
The sugar industry wants to extract the best from all sides. To the farmer this means achieving higher yields and minimal crop losses. Thus, mechanical harvesting solutions are constantly evolving. Today, the market already offers harvesting machines that only cut off the leaves with a sharp blade. This is called MicroTopping and it increases yield. Other systems break off leaves. In the end, it remains questionable whether the higher costs of acquisition really always pay off. There are also solutions that enable an automatic speed adjustment of the cleaning elements according to the throughput. This results in a gentler and more efficient cleaning of the beets with reduced losses.