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