By David Jones, Broad Acre Agronomist, Msc. Agriculture

In Part 2 of our series looking at Controlled Traffic Farming (click here for Part 1) we take a look at why the approach has been less than widely adopted in many areas of the world, but why it is still highly relevant here in Kenya.

Even in Australia, the largest adopter of Controlled Traffic Farming the figure is put around 30% of land is farmed under Controlled Traffic, yet this of course varies significantly across the country. In Europe it is estimated that less than 100,000 hectares are managed under CTF, and in the whole of North America less still despite the obvious benefits from the scale of equipment and low rainfall (good soil structure is more valuable).

Taking Northern Europe or New Zealand as examples, one would assume that higher yielding crops would mean greater potential to increase yields from reducing compaction.

I have spoken to several colleagues, read numerous research papers and scanned some exceptional Nuffield Scholarship reports in the last week to try and understand what is holding back the adoption of CTF.

For anyone seriously considering moving to a CTF system, understanding the challenges is crucial to making it a success.

soil compaction

It is a common misconception that you need large, high tech kit to benefit from Controlled Traffic Farming. Narrow track width harvesters like this actually make it easier to set wheel track width in the system!

‘Systems too complex to change’

The first major observation is that it is difficult to find research in Europe that categorically shows a consistent yield benefit from CTF, year on year. This sounds incredible but some of the best researched studies I encountered from Bavaria in Germany for example showed a very limited benefit, however they did clearly identify that the yield difference was greatest in the dry years during the study.

Many countries in the world with the highest average yields also tend not to be higher rainfall, have farming systems based around cultivating rather than no-till, where more machines – cultivators, presses, slurry spreaders for example – need to fit into the required width of the system. Not to mention the alleviation of compaction from cultivating.

Farmers often tell me that they see the changes required as ‘too complex’ on their farms, a perception that is largely unfounded. However, if rainfall is not your limiting factor and your soil structure is generally good, the upside from CTF may be limited.


Wheel Traffic induced Soil Compaction

Narrower equipment means more wheelings, which in turn means less benefit from CTF.

Medium scale farmers in Kenya aspiring to the system are also warned that smaller machinery with narrower working widths mean more wheelings anyway; thus compared to a 12:36m Australian CTF system (12m planter and harvester, 36m sprayer) which might traffic just 15% of the field, a 4:24m system would still traffic over 40% of the soil.

If you have a narrow planter and harvester, expect minimal benefits from the system. But bear in mind that Kenya does not however benefit from self-structuring soils such as chalks and flinty clay loams, so once compaction is in place it is needs rectifying. Avoiding compaction in the first place is much cheaper.

Consideration needed for farms reliant on contractors

Farmers using contractors with varying sizes of machinery also need to be realistic. Operators have to be well versed in using GPS guidance to stick to your track lines too.

That said don’t let this stop you, as you can still have most of the benefits of CTF and use a contractor to harvest on a dry soil. Just don’t go driving over the field if you decide to bale the straw.

Verdict in Kenya?

  • CTF makes a great deal of sense agronomically in terms of soil structure.
  • It is a must if you want to move towards notill or farm soils that are highly prone to compaction such as Black Cotton.
  • If you are largely cultivating the benefits will be minimal.
  • A plan is needed for gradual machinery replacement is needed to purchase the right sized equipment for the system. Transition to full CTF can take time.
  • For large scale farmers with bigger equipment, on GPS guidance, particularly those operating notill systems, CTF is a no brainer if only to reduce machinery overlaps and improve efficiency.
  • The challenge is often adapting equipment to wider track widths of the harvester which we will explore in next week’s #ThinkAgronomy.

Keeping up the Pressure on Sclerotinia for Top Canola Yields

Now that Canola harvest is complete in many areas of the country, I would urge all growers to examine the levels of Sclerotinia in their crops to measure the success of their control programs.

Even where the crop has been grown for the first time, Sclerotinia spores can blow into the crop from neighbouring brassica growers, or survive in the soil for up to 20 years.

It is very important to know how to identify the disease which can cause up to 50% yield loss.


Conventional wisdom is that every 2% infection equates to 1% yield loss but I think 1% infection is virtually 1% yield loss. Where growers are seeing direct infection largely on the roots (tends to be seen in high OM soils), fungicide sprays at flowering will not help this as the infection has already taken place.

Earlier sprays should be used in this instance, and our trials here with the Agventure Centre of Excellence for Crop Rotation here in Kenya have shown that a spray at green/yellow bud stage in addition to the traditional Phoma spray at 4-6 leaves can half direct root infection, worth +0.3 t/ha.

The next step is looking at in-furrow fungicides, to place protective strobilurins right into the root zone at planting.

Thinking of Liming? Avoid costly mistakes like this…

Limestone quality analysis

Lime quality – and effectiveness – varies enormously. Just look at this recent sample that I purchased for trials.

Back in March I bought lime for some of my work that showed a fine particle size (96% below 2mm) and an Effective Calcium CO3 equivalent (how well it will react in the soil) of nearly 93%.

Before I ran out I purchased some more from the same supplier in September but had it tested to affirm the quality. Only 79% will go through a 2mm sieve, so 21% will never react, and it is half way between Calcitic Lime and Dolomitic Lime in chemical composition.

Moral of the story; get your lime tested before you pay for it.

Farming for the future requires a change of approach. Monoculture, soil degradation and climate change and soil degradation are threats to the future of how we feed the planet.

Agventure Ltd set up the Center of Excellence for Crop Rotation to help farmers diversify cropping systems and introduce techniques which have a long-term outlook to improve soil health.

The Center of Excellence for Crop Rotation works extensively with Crop Nutrition Laboratory Services Ltd (CropNuts).

Till next time,

Happy farming,


About David

David Jones is the Broad Acre Specialist at Crop Nutrition Laboratory Services Ltd. (CROPNUTS). David has a keen interest in soils and no till farming systems where he has undertaken work looking into weed levels and changes in soil structure, and has extensive experience in field trials and in the development of precision farming techniques. In his spare time he enjoys playing rugby.