Inconsistent results from seeding oilseed rape using a
subsoiler have led many growers to revert to cultivator-based
sowing for reduced-cost establishment. Peter Hill describes a
farmer-contractor's evolving system
Providing loosened soil below rapeseed to encourage good
drainage in a wet season and to give roots somewhere to go in a dry
one is well proven as an essential component of establishment
systems that do not involve ploughing.
But while the "extreme" technique of seeding from a subsoiler
and relying on natural weathering to provide a surface tilth has
met with inconsistent results on many farms, soil loosening is no
less important when using a cultivator-based sowing technique.
Lincolnshire contract farming manager Mickey Daly has tried both
approaches on the blocks of land he manages around Spalding and
agrees that both have their merits - but also their
limitations.
"With subsoiler broadcasting, you really need a well-weathered
surface and even then getting adequate soil-to-seed contact for
even germination is not very likely," he says. "Broadcasting from a
cultivator overcomes that by creating a nice tilth. But then you
don't get the benefits of deeper soil loosening to take out
wheelings and ensure the plants' long roots can grow to full
potential."
Mr Daly grows plenty of oilseed rape as managing director of
Agriserve, which was set
up to spin off the machinery and labour inputs of JL Farms and
spread machinery investments through contracting and contract
farming operations. This year, that all adds up to a workload
equivalent to about 2000ha (5000 acres).
The crop features in his heavy-land rotation along with beans
and winter wheat, but is absent from the light fenland mix of
potatoes, sugar beet, peas, wheat and 122ha (300 acres) of pumpkins
farmed by a specialist grower.
"Oilseed rape is still a useful break crop, as well as one with
good profit potential," says Mr Daly. "Our objective in developing
a broadcast sowing system is to cover the ground quickly to get our
own and customers' crops established while grain harvesting
continues and get even germination for ease of management."
When deciding to move away from the traditional establishment
approach of ploughing, pressing and drilling, or using a power
harrow-seed drill combination after ploughing, the objective of
cutting costs brought with it a reluctance to buy new machinery for
the job.
"Our first approach was to sow using a
Techneat Terracast system mounted on a
Knight
TriplePress set to work no more than the top 50mm (2in) of
soil," says Mickey Daly. "That worked well in terms of providing
fast work rates and a tilth for good seed/soil contact, but it
didn't take out the wheelings."
Putting a second Terracast unit on to a seven-leg
Simba Flatliner equipped
with a DD press took care of the wheelings and also provided the
benefits of deeper soil loosening.
But although seed/soil contact was often good, that was not
always the case where a lot of chopped straw was present.
"In some instances, we ended up with parts of the field
establishing up to a month behind the rest, and that makes life
difficult," says Mr Daly.
Using the two implements in the same field brought home their
relative advantages and especially the benefits of loosening soil
beyond seed depth.
"You could see to the line where the Flatliner had been,
especially on headland areas, and it was noticeable that we no
longer saw the purpling leaves of plants stressed by poor drainage
conditions," he says.
The obvious answer was to combine the two elements and, as a
matter of urgency, this was achieved in the first instance by
running the TriplePress and Flatliner in tandem, each applying half
seed rate.
In terms of crop establishment and early crop development that
was a winner, even if it was not economically sustainable, says
Mickey Daly.
"It produced a much better plant going into the spring and now
we're looking at some of our best ever oilseed rape crops, with
fewer, stronger and healthier plants and a branching structure that
interlocks nicely; hopefully, making them easier to harvest."
Moreover, the questionable economics of running two implements
on the job will be resolved this year when the two Terracast units
are transferred to a
Gregoire-Besson Discordon cultivator acquired last autumn.
This 6.7m (22ft) implement uses a leading row of discs to bust
stubbles, then 13 low-draft rigid tines to break through any pans
or compaction across the full working width.
Another row of discs follows to break up and level any clods
thrown up by the preceding elements, with press rings bringing up
the rear to consolidate the resulting tilth.
"We tried it to sow some oilseed rape last year, using the
Flatliner for broadcasting and rolling after the Discordon, just to
see what we could expect and the results were excellent," says Mr
Daly.
Installing both Terracast units will allow half-width sowing on
short-work in addition to easy adjustment of seed rate if required
using the electronic control system.
The Discordon will also get a clevis coupling on the back so
that it can tow a roller press.
"If it's too wet, we'll take it off and use a
Cousins
Contour Cambridge roll or
Väderstad Carrier with the discs raised out of work to finish
the job," says Mr Daly. "But at least we'll be able to do the
complete job in one pass if the weather's kind."
Another objective - of covering the ground quickly - will also
be achieved by operating the outfit behind a four-year old 550hp
Case IH STX500 Quadtrac that recently joined the fleet.