A spade is one of the most frequently used tools on Richard Hinchliffe’s 480ha (1,200-acre) farm, which he runs with his father, David, near Goole in Humberside. The soil type is predominantly warp marine alluvium, an artificial soil created through years of deliberate flooding.
“It compacts fairly easily,” says David. “You have to be very careful how you handle it.”
No crop demands this care more than oilseed rape – this year there’s 90ha of Excalibur, Vision and some Pioneer dwarf hybrids. But they have achieved impressive yields – 5.0t/ha has been recorded, although the farm average is closer to 4.7t/ha off this consistent, but tricky soil type.
“The key to everything is the root,” David asserts. “It’s an inefficient plant at scavenging nutrients and a poor rooter. So we set out in autumn to do everything we can to get the root off to a good start.”
Mindful of compaction, field traffic is kept to a minimum. Crop residue is chopped then incorporated with a Horsch FG cultivator 24 hours behind the combine. This is then left a month to get a blackgrass chit and may be repeated crossways to get a more thorough mix and a better tilth.
For more on this: See all of the articles on High 5 OSR yields
“We pull a flat lift or a tailor-made Watkins subsoiler through those fields that need loosening.”
This is where the spade comes in. In late spring David and Richard make detailed inspections of the crop below ground to assess the success of their autumn regime and spot areas of compaction.
“We’re looking for a good, long tap root that’s driving down for moisture. You need plenty of fibrous laterals too. In a year like this, without a good root system, there’s no doubt yield will be compromised.”
It’s with this in mind that the seed-bed is prepared and the crop drilled. “We’re aiming for friability on top and structure below.” They may make a pass with a Väderstad Rexius Twin with its tines and press rings if required, or go straight in with the Horsch drill.
As a matter of course, 30kgN/ha is applied to the stubble, spun on as 10.25.25 NPK. “I wouldn’t grow a crop of oilseed rape without autumn fertiliser. The crop wants nutrition that early in life.”
An evenly spaced crop of 30-40 plants per sqm with four to six leaves each is the aim before winter sets in. “We don’t like crops to get too proud – they barely want to cover the toes of your wellies.”