PHOTO: ROHAN RAINBOW PHOTO: ROHAN RAINBOW
PHOTO: ROHAN RAINBOW
CONTROLLED TRAFFIC FARMING ▶▶▶
Australian growers halt worsening of soil compaction with CTF
BY RENÉ GROENEVELD S
oil compaction has been an issue in Australia for well over 30 years. “Par- ticularly in the last 15 years producers in this country have adopted high
rates of Controlled Traffic Farming (CTF). The rate of adoption for no-till practices in broada- cre is over 85%. Almost half of those producers are practising some degree of CTF,” Dr Rainbow says.
He points out that CTF is generally recognised for its production and efficiency benefits. “When it’s wet, it’s not such a big issue to get over the ground. But the impact of compaction, the improvement in crop growth and yield are also well understood here. This is primarily why there are such high rates of adoption.” Many Australian soils are not high quality, Dr Rainbow says. “In a clay soil with shrinkage and contraction, and wet and dry periods, the hard pan soils can actually break up again with time. But if you have a higher sand content (e.g. in loamy sands), you don’t have those phenomena. It just gets harder and harder.”
Gradual conversion
Research data has now proven the value of Controlled Traffic Farming (CTF) across a wide range of soil types. Modelling data from Western Australia showed an AUS$ 200,000 cost of conversion to CTF (US$ 145,000), which can be paid back in two years, assuming yield increases of about 9%. A study in southern Queensland indicat- ed that a 17 per cent return on capital was achievable from converting to CTF with an AUS$ 137,000 investment (US$ 100,000), with a payback period of 5.9 years. The con- version to CTF should be a gradual process in line with standard machinery replace- ment strategies. Bigger machinery is not al- ways the most efficient approach and grow- ers are encouraged to record their actual
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Growers in Australia have basically halted the worsening of soil compaction with controlled traffic farming, says Dr Rohan Rainbow, Managing Director of Crop Protection Australia. “It’s the dominant best practice farming system in this country.”
Dr Rohan Rainbow: “CTF is recognised for its production and efficiency benefits. Traffic- ability is also higher. When it’s wet, it’s no longer an issue to drive over the ground.”
Advantages of good soil There is a simple test, Rainbow explains. “You take a 3.25 mm high carbon welding rod with
the flux removed. If you can press the rod with your open palm all the way into the soil, you are below the critical threshold of 2.5 meg- apascal soil resistance. However if it hurts too much to do this, you are above that threshold. It’s not easy to see compaction, but you can feel it.” Improved soil structure through reduced com- paction results in improved water holding ca- pacity. There is also improved efficiency of some soil immobile nutrients by placing fertil- isers closer to the plant. The soil is in better condition to provide nutrients to plants. Stud- ies worldwide have shown that the uptake of fertiliser improves by around 15%. Another advantage is the lower tractor capital that is needed. Firm, permanent tramlines and softer soil in between improve tractive effi- ciency, reducing average power requirements. And all these benefits will result in improved crop yields. In crops of lupins there is an ad- vantage of 10%, in wheat 13% and in canola producers gain 11% using CTF.
It can take ten years to get your machin- ery suitable for CTF.
field efficiency with current gear. It can take five to ten years for growers to fully match their machinery for CTF, taking into account sound financial management to replace ma- chinery when it is due for replacement and not any earlier.
▶ FUTURE FARMING | 20 November 2020
High rate of autosteer adoption Dr Rainbow explains how farmers have halted the worsening of soil compaction in Australia with CTF or tramline farming. “We have aligned the wheel tracks of our tractors, spray units, harvesters and so on commonly at 3 me- tre centres, sometimes 4. And there is also a very high rate of autosteer adoption, now probably more than 90%. Autosteer makes the control of CTF systems a lot easier.” Australia was one of the first countries to de- velop CTF. “It’s not easy readjusting all the wheel tracks. All the major machine companies – John Deere, Case IH, New Holland, etc. – have designed and built tractors for the Australian market. Typically front wheel assist
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