On the Wills Estate, Edgcote, which straddles the North Oxfordshire and Northamptonshire borders, manager Hamish Gairdner has swapped to precision planting in an effort to help oilseed rape grow away from flea beetle.
Part of a four-year rotation on 670 hectares of combinable crops with two wheats and spring barley or beans, plus some grass, 150ha of OSR was established for this year.
For the 2018/2019 season, establishment was switched from a Vaderstad TopDown and mounted BioDrill to the Swedish manufacturer’s Tempo precision drill. Ground preparation is carried out with the TopDown, fitted with Grange low disturbance legs in place of every other leg at 52cm spacings, and a six-row Tempo R has been bought.
“The Tempo is set at 50cm spacing working into the small amount of soil disturbed by the Grange leg, and we use RTK to ensure accurate guidance of the planter,” says Mr Gairdner.
“We always double rolled after the BioDrill to ensure seed to soil contact and retain moisture, and this has continued with the Tempo as I believe this is the most important cultivation pass you can make,” he says.
“But the Tempo must be set up correctly to avoid producing a ridge the roll can’t consolidate.”
He adds that if this can be achieved, the Tempo produces a level seedbed.
“The star wheels at the front need to be adjusted to just clear any trash, rather than moving too much soil.
“We bale wheat straw, so after this the pressure of the coulter is sufficient to cut through the trash; after barley where we chop the headlands, the wheels can be reset to move residues if necessary,” he explains.
Setting the rear press wheels correctly is also key, he says.
“We avoid using too much pressure which might create a large ridge – the rolls can press down a 5-10mm ridge and give good seed to soil contact.”
To test the system, Mr Gairdner initially engaged a contractor with a Tempo designed for maize, working at 75cm spacings, drilling twice to give 37.5cm row widths.
“This was too close and we also tried drilling a section at 75cm, which showed no yield loss, but suffered from increased weed competition in the wider rows, hence the decision to choose the Tempo R with its 50cm spacing.”
It is fitted with a 1,200-litre fertiliser hopper. In the first year, ammonium nitrate (AN) was placed down the spout, but for 2019/2020 it was swapped to the more commonly used DAP.
“With reflection, the AN gave a better start, so we will return to that this year. Not only is it cheaper but it is more readily available to the crop.”
Double rolling is an important part of the flea beetle strategy, then spraying is carried out at night to minimise impact on the estate’s 100,000-plus bees.
It is a strategy that seems to be working. Mr Gairdner says that corner to corner coverage is visibly better than with the BioDrill. In-row spacing is 5.5cm, with seed rates at 2.6kg/ha, and Mr Gairdner puts establishment at 95 per cent.
“Seedlings emerge evenly over a three-day period, rather than at scattered timings, so there is less flea beetle pressure on individual plants,” he says.
This year’s crops have been as variable as anywhere else, but Mr Gairdner is encouraged by last season’s results.