I first heard of CTF a few months ago. It's something of a novel concept here in the UK but in parts of Australia and the US it seems to have taken off. According to www.controlledtrafficfarming.com, a British website, controlled traffic farming (CTF) is 'a whole farm approach to the separation of crops and wheels; it is a system that avoids the extensive soil damage and costs imposed by normal methods. Controlled traffic is not rocket science - it simply involves confining all field vehicles to the least possible area of permanent traffic lanes.'
' "Plants grow best in soft soil, wheels work best on roads" neatly encapsulates the major conflict at the centre of most mechanised agriculture, and the rationale for controlled traffic farming,' according to CTF and Climate Change, a paper published for the 6th Australian Controlled Traffic Farming Conference. The paper describes how, by combining zero tillage with using tractors and machinery only on clearly identified (usually via GPS) permanent tramlines, and avoiding all movements on other parts of the field, soil structures improve, energy used in subsoiling is saved, water retention improves and runoff declines, resulting in improved yields and / or greater cropping frequency.
There are some technical hurdles to overcome when setting up a CTF system, according to www.controlledtrafficfarming.com. Appropriate agronomy and management is necessary to maximise the potential of the cropped areas and permanent tramlines, and the ideal setup is for all machinery to have the same wheel track so that they all 'fit' the permanent wheelings. In addition, all machinery should have the same span or multiples of that span to avoid covering (e.g. spraying) parts of the field twice. However, the website suggests that this is not absolutely essential – the percentage area of the field 'wheeled' can be reduced to 30 – 40% even with two different track and implement widths.
In addition to the cost of adapting (or purchasing) machinery, CTF systems also benefit from the use of GPS to identify the permanent tramlines, although marker posts could be used as an alternative.
Another paper, simply entitled Controlled Traffic Farming, refers to the use of GPS systems in almost all field systems but also highlights the cuts in fuel, labour and machinery costs as a result of reducing soil damage. 'This makes farming simpler, more reliable and less time consuming. It also delivers environmental benefits, such as reduced water run-off and soil erosion, improved fertilizer use efficiency, less risk of nitrous oxide and methane emissions and improved carbon sequestration.'
CTF has been covered in the farming press but is still a somewhat novel system. A 2008 story in Farmers’ Weekly described a Yorkshire farmer who saw it as a way to ultimately reduce crop input costs by 25%. The farmer, Mr Evison has ditched the plough and power harrow in favour of a Spaldings Flatlift soil loosener, which is often the only cultivator used, to remove any compaction from previous cultivations or harvesting operations. An additional set of discs and packer is used when necessary to create a shallow stale seed-bed for weed control. You can find out more about the costs and benefits of CTF in this Farmers’ Weekly article from 2008.