A recent story on the cover ofGrainewsgot a lot of people’s attention, and maybe not in a good way. The story “The case for controlled traffic farming” presented several reasons why CTF works in Australia and New Zealand, but many asked if there’s any proven benefits for farmers on the Canadian Prairies. To date there have been no definitive, scientific studies conducted on CTF, and the scientific community advises farmers to be very cautious before deciding if CTF is suitable for their operations.
As a research scientist, Dr. Ross McKenzie, agronomy research scientist with Alberta Agriculture &Rural Development (AARD), recogizes that CTF is a technology that has been successfully utilized in other areas of the world. “However, it will take considerable time and effort,” says McKenzie, “to determine the various soil types, agro-ecological areas and climatic conditions in Western Canada where CTF may or may not work successfully.”
The only study currently underway in Canada is a farmer led on-farm project in Alberta, which got underway in 2010 in association with Controlled Traffic Farming (CTF) Alberta (and primarily funded by the Alberta Crop Industry Development Funding and three producer commissions.) The project aims to try and evaluate whether CTF could work in Alberta, and under what circumstances and conditions. That involves assessing the agronomics, economics and logistics of a CTF system, says project leader Peter Gamache.
The premise behind controlled traffic farming is controlling and minimizing where farmers drive in the field rather than how many times they drive in the field. CTF establishes permanent tramlines on which all equipment is driven.
Any farmer aims to reduce the amount of traffic in his fields, for many good reasons, both economic and physical. There is no doubt that systems like no till, direct seeding and precision agriculture have already helped towards that goal. But certain operations (like harvesting), which create traffic in the field, still have to be done and it’s the large equipment like combines and grain trucks that potentially have the largest impact upon the field, especially if conditions are not ideal.
One of the reasons given for adopting CTF is its benefits for soil management, particularly in reducing soil compaction, improving soil quality and reducing erosion problems in the soils that are not being driven over.
“I think there is this general perception that compaction is not an issue on the Prairies,” says Dr. David Chanasyk, soil science professor at the University of Alberta. “Unfortunately compaction is a bit like erosion, when it occurs it can be a catastrophic event phenomenon. For example let’s say over a 10-year period, a farmer has nine harvests that are really dry and only one is wet. It is possible that the farmer could do a lot of damage with one pass of the equipment in that wet year, because 75 per cent to 90 per cent of compaction, when it does occur, does so in the first pass.”
Nevertheless, McKenzie feels that, generally, compaction problems in Canada are not as widespread or severe as Australia, where CTF has helped. The major reason, says McKenzie, that we don’t have the same compaction issues as Australia is because our soil types and environmental conditions are very different. “Compaction problems generally are a greater concern on Australia’s soils that are more than a million years old and are very highly weathered. Western Canadian prairie soils are very young, around 10,000 to 12,000 years old, so our soils are not highly weathered.”
McKenzie notes that Australian subsoils that are more subject to compaction tend to have higher levels of sodium, which contributes to poorer soil structure. In Western Canada, most of our cultivated soils have subsoil that tends to have higher levels of calcium which contributes to good soil structure. The exception on the Prairies are Solonetzic soils have relatively high levels of sodium, with a naturally hard subsoil layer below the topsoil.
He also points out that the types of clays in Australian soils tend to be non–swelling clays with do not swell and shrink with wetting and drying cycles. The types of clays in Canadian prairie soils do swell and shrink with wetting and drying cycles. Further, Prairie soils are subject to annual freeze-thaw cycles while Australian soils are not. The freeze-thaw, wetting-drying and swelling and shrinking of western Canadian soils tends to dissipate compaction that may develop from agricultural equipment.
McKenzie said that it is critically important to be aware that the physical and chemical conditions of Australian soils and their environmental conditions can be quite different than western Canadian prairie soils, therefore, we must use caution to carefully study CTF to ensure we understand all potential benefits and challenges before we encourage farmers to adopt this new technology.
STILL A FIT?
Chanasyk agrees entirely that our soil and climate combinations are very different from those in Australia, but he also notes that variability of soils within Western Canada could also play a factor in whether a system like CTF would be of benefit or not.
“For example, the soils just to the south of Edmonton are wonderful soils. There’s 40 cm of topsoil with high levels of organic matter and it’s very resilient, so you can drive over it and it doesn’t really matter,” says Chanasyk. “But if you go 150 kilometres east of Edmonton, you go into a soil belt where the topsoil could be as shallow as 10 cm and below that is a really hard sub-layer high in sodium and clay (Solonetzic soils). These soils are really touchy in terms of being trafficked. You have to manage them carefully and till them at the correct time, which means you can’t drive on them when it’s not the right time. So in those kinds of instances make a lot of sense.”
McKenzie believes that the move towards zero till and direct seeding systems across Western Canada over the last 20 years have significantly helped to alleviate many of the compaction problems (mainly soil crusting and plow pan layer development) that used to be caused by more frequent cultivation. He also feels that these systems have already significantly improved soil quality by increasing organic matter, improving soil structure, improving nutrient-holding ability, improved water infiltration and encouraging deeper roots, and that it would be hard to see how CTF could enhance that unless, again, there were significant compaction problems to begin with.
Chanasyk agrees that in terms of tillage, CTF would appear to make more sense under conventional tillage systems, which require many more passes over the same field for different operations.
Harvest time, however, is when a lot of damage to fields can potentially occur, especially if conditions are wet, and CTF does still presents some logistical
challenges when it comes to harvest. “The biggest question everyone has is about harvest logistics,” says Steve Larocque, the producer who is involved in the on-farm study near Morrin, Alta. “If you are running two or three combines down straight lines you can’t just go diagonally and head right to the approach where the truck is, you have to follow the tramlines down to the end, drive the headland and then drive out, so it’s not the shortest distance.”
Questions have also been raised about the feasibility and cost of adapting current farm equipment to run on the spaced tramlines, but logistics shouldn’t always be a deterrent to experimenting with a new system, says Chanasyk. “If you could prove there’s a benefit, then maybe these things are something that can be handled,” he says.
ECONOMIES OF SCALE
A big part of that logistical decision may be determined by the fact that farmers have a very small window of opportunity to get their seasonal work done, which might make it a bit of a tough sell for many farmers. “CTF works well in Australia because they don’t have such a short window of opportunity to get the seed into the ground as we do here in western Canada,” says Mike Bevans, an engineer with AARD and a precision agriculture specialist. “They seed into dry soil and wait for the rainy season to come, so they have a long period of time to seed.”
As a result, Bevans questions whether Canadian farmers, who are anxious to seed as quickly as possible, and often have 60- to 90-foot seeders to accomplish that, would want to go down to a 30ft seeder, which is the common width to which all farm equipment is sized for CTF. “It might be difficult to persuade a farmer with a 60-foot seeder to go down to half a size, so either you buy one more piece of equipment to do the same amount of land as you used to be doing, or you take twice as long to seed,” he says. “Many farmers might see too much risk in potentially taking double the time to seed.”
Other potential benefits that are also being looked at in the CTF experiment being done in Alberta include potential fuel savings and more accuracy in the application of crop inputs. Bevans believes that, in terms of realizing efficiencies due to reducing overlap, CTF would be hard pressed to provide any additional benefits if farmers are already using precision ag. “CTF generally encompasses three components,” he says, “a precision ag guidance system (like GPS), inter-row seeding and equipment modifications to run on tramlines. The GPS alone is what gives the increases in efficiency and reduction of overlap.”
Bevans advises farmers to consider starting with GPS and inter-row seeding and wait for some
hard scientific evidence on CTF to see whether adding the final element of CTF (the tramlines) would offer enough benefits to their operation to make it worth the time and investment needed to implement it.
Chanasyk agrees that there is still a lot of research to be done to build on the Australian experience and apply that to conditions in Western Canada, but he does believe it is worth investigating the potential for CTF.
McKenzie advises farmers to use the same critical thinking about CTF that they would with any other farm management decision. “Consider the conditions that they have in Australia, and compare them to the conditions we have here and ask whether this technology could apply to their soils and farm operation?” he says.
Chanasky thinks that’s probably something farmers will do as a matter of course. “Farmers are pretty astute people and they are not going to invest a whole pile of money in something they are not sure of,” he says.
The Alberta group will continue to explore the benefits and challenges of CTF and will hopefully help add to the knowledge about where it might work best and where not. What is certain is there is always more than one way to do just about anything, and farm production management is no exception. For every problem encountered there are lots of options, and in each case it’s usually the situation and conditions which dictate the answers. And it’s often a case of taking what works from many different options and making them fit together to build a stronger solution that works for each farm operation.
CTF works well in Australia because they don’t have such a short window of opportunity to get the seed into the ground as we do here in Western Canada