Unilever R&D Colworth Controlled Traffic Farming Project
Project extension, 2006
As from September, the single 8 ha field converted to Controlled Traffic in September 2004 (see more
detail below) on a clay soil has been augmented by eight others, bringing the total area up to 73 ha.
Wheat and oilseed rape have been direct sown and winter beans will be similarly established as soon as
soil conditions permit. Some of the new fields going into CTF were deep loosened; some because their
condition was known to be poor, but others were loosened to provide a direct comparison between fields
that were in the same position in the rotation. We will look at the relative performance of the crops
in these fields as well as the soil conditions. As the conditions were very dry when the first CTF
wheelings were established on these new fields, no in-filling has so far been necessary, but this
situation will be reviewed after harvest next year.
Guidance of the vehicles has remained with the John Deere SF2 system, but as we want to keep the wheel
tracks in exactly the same place from now on we have installed permanent markers that are
resilient to the conditions. We had to think carefully where to put these! They had to be somewhere that
could be accessed by harvester and tractor + drill etc. very easily from the field entry point, and in a
position that could be driven over on the correct bearing. Only when machines are positioned centrally
over the marker can the driver press the "shiftrac" button on the guidance system to set it up
correctly. We could avoid this by using an RTK system (local base station) but we won’t do this until
we can see that it can be justified on the economics. We are presently developing some calculation
tools to help us carry out this analysis.
We now have an increased farmer membership of the group (23) and in addition to Unilever, John Deere,
John Dale Zero Till, Farmade Management Systems and Michelin Tyre plc we have welcomed John Rhodes
Ag Services (Berthoud) and Yara as sponsors of the project.
Project initiation, 2004
In September 2004 a group of industrial partners and farmers came together to formulate and trial a
controlled traffic farming (CTF) system in the UK. The aim was to learn about the practicalities
and sustainability of CTF, monitor its benefits and shortcomings and assess its commercial potential
for the farmers involved. Partners in the project included Unilever R&D Colworth, John Deere UK
Ltd, John Dale Zero Till and Farmade Management Systems. Michelin Tyre plc also provided active
support. Eighteen farmers were involved representing more than 10,000 ha of arable land in the UK.
The CTF system was based on an implement width of 6.67 m and a tramline of 20 m which matched with
the existing farm equipment (see illustration). To match the harvester track width and minimise the
area wheeled, John Deere provided an 8520 tractor with Independent Link Suspension and axles extended
to 3 m. John Dale Zero Till modified one of their drills to fit the system and a harvester was brought
in by John Deere.
Illustration of the initial CTF system at Colworth (approx. to scale). In 2006 the
primary implement width has been extended to 8 m and the chemical application to 24 m, while the
wheeltrack remains at 3 m
Guidance for the vehicles is with a single John Deere Starfire receiver and key card which we swap
between harvester and tractor. We are using the SF2 system which has delivered the predicted accuracy
(well within ± 10 cm) but we had to install a datum point to make sure that we returned to exactly the
same tracks each time. In the particular field, access to the datum point was easy as there was a
concrete track and grassed headland alongside.
Many cost-effective and simple ideas are emanating from the project and a number of the farmers are
now actively pursuing conversion or have converted to CTF.
Results from the single 8 ha field in CTF at Unilever R&D Colworth have been encouraging. Within about
12 months the topsoil conditions improved compared with surrounding conventional practice on the same
soil (see photos) and some comparisons of water infiltration
indicated a substantial increase over similarly managed but trafficked soil (see table). The results for
ploughing might appear impressive, but there was marked evidence that the water infitrating rapidly from
surface was merely going to plough depth before being held up by a compact layer. Although we
were unable to harvest the crop of wheat at the end of the first year (nothing to do with the fact
that it was in CTF), the subsequent crop of oilseed rape grew vigorously (see photos) and yielded
4.2 t/ha. Although this was no greater than yields from surrounding fields under conventional
management, lack of any replication of treatments would not allow us to make valid comparisons.
Penetration resistance was also lower on the CTF field than on neighbouring direct drill or low
input systems but higher in the topsoil than on a ploughed field.
Conditions were very moist and soft when we first introduced the CTF wheelways so we made an initial
in-filling pass with a cultivator. Since then the permanent wheelways on the CTF site have remained
in good condition with no further management needed.
Farm staff report the system is easy to operate and the guidance system has worked well.
Topsoil twelve months after the introduction of CTF and direct drilling
Topsoil in an adjacent field that was direct drilled with random traffic
Topsoil in an adjacent field where non-inversion tillage had been used with random traffic
Water infiltration on the CTF site compared with that on surrounding fields under conventional traffic
management (December 2005)
| Treatment |
Mean infiltration, mm/h |
Standard error |
| CTF direct drilled |
904 |
167 |
| Trafficked: |
|
|
| Minimum tilled (discs) |
576 |
102 |
| Direct drilled (tines) |
179 |
69 |
| Ploughed |
5264 |
1553 |