Broad application of permanent tramlines faces many obstacles
Permanent tramlines offer more workable days and can increase yields, but research shows this is not always the case, and it takes years to realise benefits. High conversion costs of tractors and machinery, along with other drawbacks, limit the adoption of permanent tramlines.
The use of increasingly heavier agricultural machinery leads to greater soil compaction. Approximately 50% of agricultural soils in the Netherlands are compacted. In addition to low-pressure tyres, permanent tramlines (Controlled Traffic Farming or CTF) or seasonal tramlines can also address the problem of soil compaction. This is necessary because soil compaction not only limits the infiltration capacity of the soil but also the capillary rise of moisture, leading to yield losses. During heavy rainfall, more water runs off the field, prolonged ponding occurs more frequently, and nutrients and crop protection products leach more quickly. This results in yield losses and negatively affects surface water quality.
Permanent tramlines
Soil compaction and poor soil structure always result in yield losses. Growing crops on soil that is not traversed leads to higher yields over time. To minimise soil traversal, permanent tramlines or seasonal tramlines are an option. Farmers using seasonal tramlines also utilise permanent tramlines, but not during primary tillage and harvesting. Permanent tramlines mean that agricultural machinery always operates on the same fixed paths/tracks.
Outside the tramlines, the natural structure of the untrafficked soil recovers, positively affecting soil and crops. Using GPS guidance, farmers can perform sowing, planting, fertilising, weed control, spraying, and harvesting via these permanent tramlines. The tramlines become compacted through intensive use and can be traversed even in poor weather conditions, reducing fuel consumption (see box: The main advantages and disadvantages of applying permanent tramlines).
CTF still rarely applied
Despite the many advantages of CTF, its global adoption remains low. This is evident from an Australian study by Diogenes Antille in 2019. The exception is Australia, where approximately 30% of grain production employs CTF. “The incompatibility of equipment and the modification of machines, with the risk of voiding their product warranty, are significant barriers to widespread adoption,” says Antille. “As is increased reliance on contractors and regulations for road transport.”
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Approximately 60 Dutch farmers use CTF
Permanent tramlines have not yet gained significant traction in the Netherlands. Joost Rijk, farm manager at the Farm of the Future in Lelystad, estimates that about 60 farmers in the Netherlands work with CTF. “They are mainly organic arable farmers because they need to operate in the field more frequently for mechanical weed control. In the Netherlands, most tramlines are 3.15 or 3.20 metres wide with a cultivation bed of 3 metres, as standard machinery is 3 metres wide. Additionally, machines with this track width are still permitted on public roads.”
A disadvantage of permanent tramlines in potatoes and onions combined with ploughing as primary tillage is higher penetration resistance and lower yield from edge rows and ridges. This was evident from a 2019 study by Lucas Bastiaansen, a student at Aeres University of Applied Sciences, commissioned by WUR Open Crops. With non-inversion or reduced tillage, there is no clear effect of tramlines on penetration resistance. In most cases, yields remain consistent between rows or ridges within a cultivation bed.
The Farm of the Future in Lelystad has largely transitioned to permanent tramlines since 2009. This is implemented on most plots in combination with non-inversion tillage and strip cropping (3 metres wide). Crops grown include potatoes, onions, carrots, grass-clover, winter wheat, and field beans. The tramlines are spaced 3.15 metres apart; the soil in between is never traversed again, not even during harvest, which is quite unique. – Photo: Mark Pasveer
Initial conditions also important
Research in various countries shows that arable crops and vegetables on tramline systems can yield 10 to 70% more compared to non-tramline systems. However, this strongly depends on the crop (how sensitive it is to soil structure), soil type (more benefits on clay), and the number of years tramlines have been in place (the longer, the greater the effec
The initial condition is also important; the more compacted the soil, the more gains can be achieved. There is still little Dutch research indicating that CTF leads to higher yields (see box: SPNA research: no convincing added value of tramlines yet). The yield difference between permanent tramlines and no tramlines is also smaller if farmers only operate when the weather is dry and use light machinery with low tyre pressure.
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Are permanent tramlines worthwhile?
Whether permanent or seasonal tramlines offer perspective for arable farmers largely depends on the farm type, soil type, crop rotation, and land parcel layout. Bram Lommerts, field researcher at SPNA, sees particular added value of permanent tramlines for the organic sector. “Not necessarily in higher yields, but rather in the earlier and more precise control of weeds. In our region, we are not yet seeing a rise in tramline use in conventional farming. Farmers are not making the switch as long as sufficient herbicides are available and mechanical weed control is not yet the standard practice. Alternatives to protect the soil include using lighter machines or switching to wider machines to reduce the number of wheel tracks on a field.”
The cost of wider tramlines is also a barrier for many growers. Widening a tractor can quickly cost between €25,000 and €40,000 per tractor, and the same applies to widening machines.
Jacob van den Borne, an arable farmer in Reusel, opts for wider machinery. “I want to do everything at 6 metres wide with tramlines no wider than 2 metres. That gives me 4-metre-wide untrafficked cultivation beds,” says Van den Borne. He began in 2020 with a 6-metre-wide spading machine and is adjusting all machines to the 6-metre system.
“We have been planting potatoes on 6 metres for 4 seasons now. We also did trials on the effect of 4-metre untrafficked strips. It gives a few per cent more yield. We continue to use standard machines and do not modify them. Switching to 6-metre-wide machines for all operations does cost money. We have now purchased the wider versions, but that also increases our capacity.” Van den Borne is also exploring autonomous machines, such as the AgXeed robot tractor and the Nexat. “But then one with a track width of 6 or 9 metres, because 14 metres is far too wide for our small fields,” Van den Borne says.
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Farm of the Future
“At the Farm of the Future, we have grown everything on tramlines since 2009,” says Rijk. “On most plots in combination with non-inversion tillage and strip cropping. We grow potatoes, onions, carrots, grass-clover, winter wheat, and field beans. A large part of the organic trial farm is also on tramlines, though these are sometimes seasonal tramlines.”
The tramlines are spaced 3.15 metres apart, and the soil between them is never traversed again. “Not even during harvest, and that is quite unique. The tractors, combine, slurry tank, fertiliser spreader, baler, and potato harvester have all been set to a 3.15-metre track width.” A significant cost that is not always feasible for farmers, meaning that harvesting often does not yet occur from permanent tramlines.
Earlier access to fields
Rijk is becoming increasingly enthusiastic about CTF. “We can access the fields earlier and reduce fuel costs for tillage.” The farm manager observes that the soil is becoming more workable each spring and sees better crop growth. “Which makes sense with improved soil structure, drainage, and higher nutrient uptake. I can’t say much about potential yield increases simply because we are not conducting an official trial comparing yields from the tramline system with conventional cultivation.
Creating potato ridges on narrow, untrafficked 3-metre-wide strips with permanent tramlines. Most of the approximately sixty farmers using permanent or seasonal tramlines grow organically. Permanent tramlines offer particular value in organic farming by enabling earlier and more precise weed control. — Photo: Peter Roek
Rijk concludes that the 3.15-metre tramline system works well on the trial farm but that the suitability of a tramline system depends heavily on the farm’s situation. “Such as plot size, length and width, and availability of mechanisation. On farms that outsource much of their work, have many distant fields or less rectangular plots, tramlines are less suitable. Narrow track widths of 1.80 or 2.25 metres may also work well for certain crops. It depends on what you grow,” says Rijk.
Seasonal tramlines are a good starting point. But the real soil improvement gains are only seen when harvesting is also done from the tramlines. Especially in years with a wet autumn, the structural gains are quickly undone if harvesting occurs over vulnerable soil. We expect too much from wide tyres at low pressure. A trend towards heavier tractors and machines with wider implements for higher capacity still comes at the expense of soil structure. The question is whether the extra capacity outweighs the resulting yield losses.”
To further reduce soil impact, the Nexat implement carrier (see box: Nexat implement carrier covers only 5% of the soil) has been developed. Working with wider machines, such as the 15-metre-wide weeder from Zocon, also helps reduce the number of wheel tracks.
