IT HAS been more than 40 years since mechanised sugarcane harvesting changed the Australian sugar industry forever.
Few, if any, farmers long for a return to caneknives and shoulder loading.
A leading researcher and innovator though has suggested it could be time to re-think how efficient current machine harvesting practices are.
In April, Chris Norris, principal consultant of Norris Energy Crop Technology, Brisbane was awarded the president's medal for the best industry paper presented at this year's 37th Conference of the Australian Society of Sugar Cane Technologists held in Bundaberg.
Much of Mr Norris's work across 35 years has focussed on improving agricultural mechanisation systems.
He has taken a particular focus on post-harvest cane cleaning, in order to reduce trash rates entering mills and lifting cane throughput.
He also delivered one of the keynote addresses to more than 300 delegates on the topic: "Mechanised sugarcane production: forgotten lessons".
He said Australian hand cane cutting provided a benchmark to measure from.
"After 40 years, we've totally forgotten about that benchmark," he said.
The presentation drew on Mr Norris's extensive experience across a large number of global sugarcane industries at various stages of mechanisation.
As an international consultant to sugar-producing countries, Mr Norris has the rare opportunity of interacting with fledgling producers that still use hand cane cutting as well as machine harvesting.
It is with this hindsight that Mr Norris has pointed out some stark realities within the Australian industry where hand cutting has been put to history.
He says harvesting mechanisation produces serious losses and, in many ways, the industry may have become desensitised to it.
There are three areas cane harvesters impact on crop potential: the damage to next year's crop; the loss of cane in field; and the losses sustained within the mill.
His first-hand experience of other countries utilising both harvesting methods presents some startling realities with mechanisation.
"You've got, in many cases, less tonnes per hectare of product going to the mill compared to what they can achieve in the field beside them with hand cutting," Mr Norris said.
This often leads to reduced tonnes per sugar per tonne of cane delivered to the mill.
In the paddock, stool damage and soil compaction are major issues, according to Mr Norris.
He said cost pressures will maintain upward pressure on pour rates (rate of cut cane being delivered into the haul-out bin) unless there are major changes in financial drivers.
One element to this is basecutter speed with harvester operators simply driving too fast.
While in Spain, Mr Norris observed that a ratoon crop looked considerably worse after machine harvesting than after hand cutting.
The damage done may not be visible until the next season however.
"So we've got fairly substantial reductions in yield of subsequent crops as harvester speed increases," he said.
He said if basecutter speed is linked to forward speed, damage will be minimised over a wide operating speed range.
Higher adoption of controlled traffic was suggested a ready means of controlling cane paddock compaction.
Mr Norris said a trial in Swaziland has continually compared hand and machine harvesting of a 7th ratoon, 2m dual row crop grown under drip tape irrigation.
He said the owner's adherence to strict controlled traffic and harvesting speeds had found no difference between them after eight years.
"Machine harvesting per se does not necessarily mean you are going to drive your yields down- you can manage machine harvesting to avoid that issue," he said.
"We can understand fully why there has been a lot of pressure to reduce billet length but if we understood the true, true cost of reducing billet length, I'm sure we wouldn't have billet lengths anywhere as short as they are now.
"The other thing is that the industry has accepted, for quite a few years, high trash is just the norm and you live with it."
Dealing with high volumes of trash is a headache for mills which has made Mr Norris' work on in field "cleaning" all the more important.
From this perspective he speaks about a crop's potential being lowered through loss of cane in field and the losses sustained within the mill.
Cane harvesters use a set of extractor fans to suck trash out from the cane. The risk is there for cane itself to be pulled out.
It's been found that high fan speeds (over 600rpm) increase cane loss.
Each additional tonne of trash removed by the harvester takes 2 - 5 tonnes of cane with it, according to industry figures.
The cost of owning harvesting equipment for contractors and growers equates to about $800 per engine hour, meaning harvesters are pushed to get through large crops on time.
Mr Norris asked: "Do we have the option of slowing back down and does it solve the problem anyway?"
For Mr Norris, there are no easy answers but he encouraged the industry to take a fresh look at mechanised harvesting and investigate new technologies.
"There are no silver bullet solutions. Slowing the harvester down to 1990 speeds is only a very partial solution and it still doesn't give us significant reductions in the value we are destroying in the harvesting process," he said.
Relaying any of those suggested changes to harvester designs though is another matter entirely.
"Significantly, if you talk to both John Deere and Case, they put a very low priority on harvesters anyway," he said.
The manufacturers do not believe it is viable to significantly enhance the cleaning performance of harvesters, particularly given upward pressure on pour rates, according to Mr Norris.