Sugarcane cultivation

Introduction

Today, sugarcane is produced in tropical regions around the world. The top producers are Brazil and India, followed by China, Pakistan, Thailand, and Mexico. Sugarcane cultivation and processing have been mechanized in some regions, although manual cultivation continues, at least in part, in others. This page goes through the basic steps in sugarcane cultivation, from planting to harvest.

Planting

Unlike cereal crops, which are grown from seed, sugarcane is grown from whole canes or from pieces of stem called billets or setts. Canes or billets may be placed horizontally in shallow pits, furrows, or trenches in the ground, covered with soil, and fertilized. They sprout and are allowed to grow and mature for at least a year before they are harvested. Preparation of fields and planting may be done by hand or with tractors and a cane planter.

Burning

Sugarcane is ready to harvest when it has stopped growing and maturing (meaning that it has accumulated the greatest amount of sucrose that it can in its stem). In some regions, sugarcane fields are burned before or after cutting the cane. Burning removes the dead leaves from the sugarcane stalks and has the added benefit of removing dead plant matter (called trash) from the sugarcane fields. Burning can be a health hazard for those living near sugarcane fields, who inhale the smoke.

Harvesting

Harvesting may be done by hand or with machinery. If done by hand, laborers cut stalks near the base using a blade. If necessary, leaves and shoot tips are also removed before the sugarcane is loaded on a wagon for transport.

Harvesting by machine may be done in a few ways. In one method, a machine first cuts the canes near the base, leaving them laying in rows in the field. The cut canes are then loaded into trucks by sugarcane loaders, machines with claw-like arms for grabbing sugarcane. (Sugarcane cutting and loading using this type of machinery is shown in the video above on this page.) Another type uses a sugarcane harvester—sometimes called a combine harvester—that chops up the cane before expelling it into a wagon or truck. This type of harvester can be used without burning the crop.

Ratooning (stubble crops)

In some cases, after sugarcane is harvested, the remains of the cane are left undisturbed in the ground. The sugarcane is then allowed to resprout so that multiple crops can be grown without replanting. These additional crops are known as ratoons or stubble crops. One or more ratoon crops may be harvested from a single planting, depending on local conditions. Unfortunately, ratoon crops are lower-yielding than the first crop, with each crop of ratoons lower-yielding than the last. Thus, fields need to be replanted periodically.

Post-harvest processing

After sugarcane is harvested and transported to the mill, it is typically shredded and then crushed with a roller to extract the juice. The juice must be processed quickly so that it does not spoil. The juice is primarily converted into raw sugar (a non-food-grade form of sugar that can be stored or shipped elsewhere to be refined) or fermented to make biofuel.

The fibrous plant material left over after sugarcane juice is extracted is called bagasse. Bagasse is often burned to produce heat or energy in the processes of sugar milling and refining and biofuel manufacture.