Case Study 4
Farm Details
209 ha of continuous wheat and barley on Oxford clay, Kelloway clay and sand, some chalky boulder clay
and head (riverwash). In all, 13 different soil types have been identified on the farm, which is also
geographically fragmented with some fields being on the far side of a busy connecting road. Peak
levels of Take-all disease were reached some years ago and it has now receded to an acceptable level.
Until the early 1990s, minimum tillage was employed alongside straw burning. When straw burning was
banned in the UK, Mr Barbour found that his low input system was no longer reliable. Direct drilling
with a disc drill became impractical where there was wheel compaction. A contractor was therefore
employed to autumn mouldboard plough the whole farm to 200 mm depth. This was followed by farm-based
secondary cultivations and drilling. Seedbeds were often difficult to create even with a power harrow.
Grass weeds in the form of blackgrass and sterile brome built up and yields went down. It was noticeable
that crop establishment was better on the lighter soils where the tilth was finer. This improved
establishment led to better crop competition and fewer weed problems.
Introduction of Wide Span CTF
In the early 1990s Mr Barbour saw a video about the Field Power Unit (FPU), an Israeli-built wide span
vehicle with a track width of 5.8 m. The 235 hp 4-wheel drive machine was equipped with a 150 hp power
take off and the main spanning beam provided a ground clearance of 1.8 m (see picture below).
The 5.8 m span Field Power Unit showing the degree of ground clearance beneath the
main structure
Being convinced that it could improve his farming operation, he contacted Ashot Ashkelon Industries with
a view to purchasing one of their machines second hand. An FPU was delivered from Brazil in 1996 and the
work needed to refurbish the machine was undertaken in the farm workshop.
In the last 8 years there has been a gradual learning curve and a transition away from annual ploughing.
Initially, a fixed width 6 m power harrow was purchased and fitted to the FPU and this was used to
follow the ploughing operation as in the past. Subsequently a less rigorous cultivator was used in place
of the power harrow and finally, a simple tine drill was developed from a John Deere cultivator (see
picture below).
The John Deere cultivator tines used as the basis of the direct drill
In 2004 for the first time the whole farm was direct drilled, mostly in the presence of a whole crop of
chopped straw (see picture below). Other than for the harvesting operation, the farm is now on a controlled
traffic system. This consists of direct drilling across the full width of the FPU, including the wheelways
but every fifth pair are left unsown. These form the basis of the chemical application tramline centred at
29 m (illustration of wheeltracks). Liquid fertilizer (urea) is applied from these as well as all the
crop protection chemicals (fig). The sown or “fuzzy” tramlines normally receive only one pass each year,
but they are also used if a stale or false seedbed for weeds is needed in the autumn. Harvesting is with
a New Holland TX63 6 m cut machine on Goodyear 42-25 Terra tyres. Grain trailers are confined to the
headlands. The harvester wheel tracks remain a problem, both in terms of the physical depression they
cause in moist conditions and their residual effect on the following crop, even when harvesting in dry
conditions.
The FPU direct drilling into chopped straw
Benefits and Challenges
Labour input on the farm has now dropped to a total of 1.2 hours per hectare for crop establishment,
fertilizer application and crop protection. The net rate for drilling is around 4 ha per hour. This
means that a much larger proportion of the crop is sown when planned and far fewer hours are spent
farming, allowing opportunities for diversification. The time required for harvesting has remained
about the same and crop yields have gradually increased, despite a change to lower yielding milling
wheat and malting barley. The latter average at around 7.5 Mg/ha for wheat (with 200 kg/ha of N plus
30 kg/ha applied late to boost protein levels to 14-15%) and 6.9 Mg/ha for barley (with 123 kg/ha of N).
The farm was among the 1% that remained in profit during the period 18 months ago when crop prices
dropped dramatically.
The permanent wheelways have improved with time (see picture below). Creating these immediately after
ploughing was not ideal and in hindsight, a shallow tillage system operated with low ground pressure
equipment might have been a better means of transition, although perhaps more expensive. Blackgrass and
sterile brome remain a challenge. The rotary harrow is used very shallow and at high speed post harvest to
create a stale seedbed when there is enough moisture. Germinating weeds are then sprayed off. Overall
and within the constraints of this rotation, delayed drilling and a rigorous spray programme remain at
the core the weed management programme.
The nature of the permanent wheelways after approximately 5 years use
Observations
The detrimental effect of wheels is noticeable where the drill tines are working behind the wheels of the
FPU. Here they wear at about four times the rate compared with where they run in the predominantly
non-wheeled soil.
Controlled traffic has reduced the contrasts between soil types on the farm. Although change in soil
type is still noticeable in terms of increased power requirement when working on the Oxford clay for
example, crop establishment is more even across the farm. Structure on this rather difficult soil has
improved with the combination of controlled traffic and direct drilling (see picture below).
Soil structure on the Oxford Clay following direct drilling of the crop in 2003
Future
Mr Barbour doesn’t anticipate any major changes to the system that he has developed over the past 8 years.
Getting weed control right will be a matter of persistence and maximising the potential of the system.
Given the money, he would modify his harvester to match the track width of the FPU. This he considers
could easily be done on the farm over one winter, but he probably couldn’t justify the cost. Design for
the system is on a drawing board but diversification activities have taken priority. If built, the
harvester would have a wheel track of 5.8 m, but easily adjustable back to standard for running on
the road.
The opportunity for spring cropping is being considered. Unlike traditional plough systems that make
spring cropping difficult and unreliable, particularly on the heavier soils, controlled traffic makes
access easy and eliminates the problem of wheel rutting and variable seedbeds in moist conditions. It
also avoids loss of moisture, which is critical in the spring. Crops can be established quickly and
easily, and rotating some spring cropping around the farm will give a much better opportunity for the
control of weeds, and particularly perennials. The overall economics of spring cropping need to be
looked at again.