By David Jones, Broad Acre Agronomist, Msc. Agriculture
Why Controlled Traffic Farming?
In the first in a series looking at Controlled Traffic Farming (CTF) systems in #ThinkAgronomy we examine why, and look at the benefits of the approach to your soils and to your profitability.
Controlled Traffic Farming (CTF) Systems is essentially a system whereby all machinery passes in the field are restricted to a minimum number of permanent wheelings in the field, to minimise and restrict soil compaction.
As a general rule, machinery with axle loads of over 10 tons, no matter how well they are spread across the soil surface with low pressure tyres, will cause compaction at depth beyond 40cm that is extremely difficult to rectify.
With a lot of modern equipment even on medium scale farms, single axle grain trailers and combines with full grain tanks and headers commonly exceed this loading.
Back in September last year I first noticed the difference that Controlled Traffic Farming makes on two neighbouring farms while I was soil sampling for Available Nitrogen; screwing an auger in to take a 60cm sample was an awful lot easier on the farm which had adopted Controlled Traffic Farming.
Reduced soil compaction really is the be-all-and-end-all for root growth and soil health, no matter how big or small your farm is. Yet there are many other benefits that are far more wide reaching…
- Fuel saving – the more compacted soil you have, the more energy is required to work it or plant through it. Australian work suggests a 25% saving in fuel consumption on land that has been in Controlled Traffic Farming for 3 years or more.
- Drought resilience. Deeper rooting means drought tolerance. There really is nothing more to say about this.
- Waterlogging resilience. Increased soil porosity and drainage channels created by worms allows water to infiltrate faster and more oxygen in the root zone. In a wet season like the one we have just experienced this has a far greater impact than we realise.
- Less nutrient leaching. Plenty of studies have shown up to 15% improved nutrient uptake efficiency with Controlled Traffic Farming systems – hardly surprising as nutrient uptake is a proxy for root growth and root mass in the soil.
- Lower fertiliser use. Extensive work on soil nitrate levels has been carried out by the GRDC in Australia. CTF soils typically contain 10 kg/ha more nitrate due to increased soil porosity and microbial activity. 1,100 Ksh per hectare if you bought it as CAN fertiliser.
- More work days. Having permanent, firm tramlines allows sprayers to travel in marginal conditions. I have two clients with farms side by side where this was a stark contrast this year in May; one who has had 6 years of CTF could apply fungicide on his wheat, the other was delayed for over a week with sprayers getting stuck on soft tramlines. The cost? I would estimate around a ton/ha lost through poor Septoria control.
- Planting inter row – on a wide row spacing, being able to plant between last year’s stubble rows as opposed to on the rows has well documented benefits in reducing Take-all and Crown Rot.
Yields (tons per hectare) from notill compared to notill with Controlled Traffic (soilquality.org.au)
One notable longer term effect is a reduction in the need for subsoiling or deep ripping to alleviate compaction. It is important to realise however that this does NOT mean that you will never need to put a cultivator through again. The golden rule is always to farm what is in front of you.
Next week we take a look at how to implement Controlled Traffic Farming and why European farmers have been slow to adopt the concept..
Canola Nitrogen and Sulphur Response
Whenever someone new to farming in Kenya gives advice to me on what ‘should’ work on our soils, with our varieties and in our climate I always ask the question, “What is that assumption based on?”
When I first came to Kenya, one of the first trials I instigated was to look at Nitrogen and Sulphur response in Canola. Being a fairly demanding and responsive crop in terms of nutrients it seemed a sensible place to start.
For the third site in a row now I have seen very small responses to both Nitrogen and Sulphur in a fully scientific and replicated trial.
We need to explore further how and why this might be the case – perhaps canola is accessing Nitrogen from far deeper than we imagined and more Sulphur is being mineralised from the organic matter than was thought – but it blows apart the theory that on our soils, canola always responds to high fertiliser inputs.
A large review of the Sulphur requirement of canola recently in the UK and Germany has shown that Sulphur uptake from organic sources is far more efficient than previously thought, which may explain these findings. Deeper rooting from Controlled Traffic Farming may also be allowing the plants to explore a far greater depth and volume of soil.
At the moment my advice is to err on the side of caution and apply at least 12kg Sulphur in cereals and 20kg in Canola, particularly as we are seeing a trend of very low Sulphur in soil tests at present after the wet weather earlier in the year.
More work is needed so watch this space.
Maize Fungicide Work Shows an Unexpected Result
Despite its very high yield potential I have often noted that the widely grown maize variety 691 suffers from much higher levels of Bacterial Stalk Rot than many newer, albeit lower yield potential varieties such as DK 90-89 and P3812.
Bacterial Stalk Rot causes a yield reduction and deterioration of the grain through rotting and discoloration.
Earlier this year I set up a large fungicide trial that has thrown up some unexpected visual results.
Initially I was looking for yield responses to foliar diseases including Leaf Blight, Rust and Grey Leaf Spot, however the crop of 691 is very clean even in the untreated control areas.
What is highly visible however is the almost total absence of Bacterial Stalk Rot where the fungicide has been applied.
There are no label claims for Bacterial disease control in maize with fungicides such as azoxystrobin and I have never heard of this either. In fact, if you look at some of the American work they have also looked at secondary diseases that enter wounds or infection sites too – and these tend to be bacterial also (Gross’s Wilt for example) so should not be controlled either.
Something useful is clearly happening here though, and if there are physiological benefits on top of this then fungicides should form a core part of the maize growing strategy.
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,
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.