Moving Towards Green Cane Harvesting(2001, Vol. 22 No. 1) - SIA

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MOVING TOWARDS GREEN CANE HARVESTING

Ever since the start of pre-harvest burning there have been periodic debates surrounding its pros and cons compared with the previous system of harvesting “green.” The switch to pre-harvest burning however involved more than just the passage of fire through the cane field for trash removal. Fire sweeping through the field would blunt cane spines, drive away pests such as wasps, centipedes, the occasional snake, and reduce the tangle of vines, cow itch or other weeds which create an inhospitable environment for cane cutters. Most of all, it was part and parcel of a new technology, introduced during the sixties, facilitating loading of cane by machines, and which marked the end of manual loading.
Very soon, the disadvantages of pre-harvest burning became apparent, triggering a nostalgic yearning for a return to green cane harvesting (GCH). One estate, Long Pond, succeeded in returning briefly to GCH during the eighties. Since then chopper harvesters have entered the picture. These are sometimes used to harvest cane without burning, but with some loss of quality and, if not carefully managed, at higher cost.
Economics however has always been at the heart of the debate. It is not so much a question of whether green cane harvesting can or should be done, but at what price. Would green cane harvesting result in greater viability, would it assist in reducing cost? - these are some of the questions.

New Challenges
Today the Industry is faced with a new set of challenges. Urban areas are getting closer to and are springing up within traditional cane growing areas. For those citizens, the smoke and soot from pre-harvest burning, although momentary in duration, are an unbearable nuisance. For those with respiratory problems a cane fire may trigger a medical emergency.
The Sugar Industry must therefore take the lead by adopting more enlightened approaches. With tourism playing an ever increasing role in the economy, and as people get more aware of what is good for the environment, the daily burning of cane during crop becomes less and less acceptable. Furthermore, the whole world is moving towards conduct that improves rather than degrades our surroundings in any way. Countries that do not conform may very well find themselves ostracised.

Policy
The above considerations led to a revue of policy towards green cane harvesting. A whole-scale switch to GCH is not recommended at this time, for reasons given below.
Growers in areas where GCH is likely to be most advantageous are encouraged to begin this process without delay. Such areas are:
* Trelawny
* Upper Clarendon (already largely doing GCH)
* Upper St. Catherine (already largely doing GCH)
* Hanover hills (already largely doing GCH)
* Westmoreland hills
* St. Elizabeth hills (some GCH)
* St. Thomas hills
* Areas on the plains under drip or sprinkler irrigation
* Irrigated areas with unreliable water supplies
Areas which would not be encouraged to go immediately to GCH would be:
* Furrow irrigated Lower Clarendon
* Furrow irrigated Lower St. Catherine
* Flood prone plains of St. Elizabeth
* Flood prone plains of Westmoreland
* Flood prone plains of St. Thomas

Explanation
In furrow-irrigated areas field trash clogs irrigation canals and impedes the flow of water so that management of the trash blanket becomes an additional cost. Where water supply is reliable, such areas benefit little from trash retention but suffer reduced efficiency in irrigation and inter-row cultivation. However, where water supply is unreliable these areas might actually benefit from the trash.
Fields in rain-fed areas, for the most part, should gradually become more productive as the trash blanket adds organic matter to the soil, retains moisture and protects the surface from excessive erosion. Exceptions are poorly drained heavy clays in the lowlands at Appleton, Holland and Frome for instance, where the problem is already retention of excess moisture in the root zone over prolonged periods.

Method
The Industry is unlikely to change to GCH with existing hand cutting methods simply because this would increase the level of difficulty and unpleasantness in harvesting. To induce workers to hand cut green cane (mechanical loading is assumed) would require sharp increases in task rates with an attendant increase in production cost - which would be counter to the main goal of reducing costs. It would also take longer to harvest a field. Fortunately, chopper harvesters (combines) are designed to harvest green cane. However, only 60% of the Industry may be accessible to combines. While they too would operate at a slower pace, they at least avoid the human discomfort in cutting green cane.
There are well known advantages and disadvantages of GCH but in the end these will hardly matter as society adopts an uncompromising stance against burning. We therefore need to do more than prepare for the inevitable but should act to encourage areas more suited to begin GCH.

Main Advantages of GCH
1. Soil moisture conservation
2. Improved soil organic matter content
3. Reduced erosion
4. Improved soil productivity
5. Longer ratooning
6. Lower weed control cost
7. Less severe staling over the same period of time after cutting
8. Cleaner air during harvesting
9. Improved juice clarification in processing
10. Potentially less dextrans in processing

Main Disadvantages
1. GCH is slower
2. Workforce expansion to maintain throughput (if hand cut)
3. Extraneous matter increases in loads
4. More trips to deliver same cane to the factory
5. Increased field loss
6. Slower Factory throughput
7. Increased fire risk with large areas covered with dry trash
8. Increased cost
In summary, the main advantages to GCH are agronomic and environmental in nature. Some potential advantages may not be realised or even become disadvantages, given prevailing weather in a particular year. Agronomic gains will be realised gradually over time while the operational challenges and costs will be immediately felt. Nonetheless, the Industry needs to make the first steps along this difficult path - now. We must do this on our own accord and invite other industries to follow.
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