By Katrina Macarthur

MINIMUM tillage is growing in popularity across the country, particularly for those who grow oilseed rape after cereal crops or potatoes.

Although conventional systems are still very much at the heart of agriculture – especially in Scotland – growers who have made a switch to a min-till system are now seeing reduced established costs, improvements to soil structure/condition and at the same time, are saving on man-hours.

Mike Cummings, who is farm manager at Lour Farms, Ladenford, near Forfar, introduced a min-till operation to the unit eight years ago and while 75% of the cropping programme is still on a plough-based system, around 300 acres of potatoes and oilseed rape ground is cultivated with a Sumo Trio one-pass stubble cultivator.

"We introduced the min-till system in an attempt to avoid ploughing down field leavings or tubers which have been left in fields after the potato harvest – they would always come back and haunt you when you're sowing wheat after," said Mike. "After the potato harvest, you're left with stubble or black earth which contains remains of tatties. Our previous practice was to obviously just plough the ground up, but the plough just buries the tatties further down into the ground.

"Using the Sumo Trio, there is no soil inversion, so the tubers are left on the top layer of the soil and then come winter time, the frost gets rid of them," he added.

In the last six years, Lour Farms has been using this method for cultivating ground before sowing oilseed rape and four years ago they added an Opico seeder unit to the back. Since using this machine, oilseed rape yields have increased by 0.3t/acre and Mike believes that is down to wider spacing allowing branching out of the plant.

"The only downside of moving to min-till is that stubble fields have to be clean and the machine won't cope with chopped straw. In some fields, we used to apply two applications of slug pellets but you definitely have to be more careful from a slug pellet point of view. It works better if barley is treated beforehand," commented Mike.

Father and son team, Finlay and Stewart Russell, who also farm in the Forfar area, at Drummietermont, Letham, have also seen improvements since moving to a min-till system before sowing oilseed rape.

"We used to do 50:50 conventional and min-till for oilseed rape but now it's all done with a Sumo Trio – a six-leg subsoiler with disc coulters connected on the back," said son, Stewart. "We're purely doing it because we only grow spring barley, rather than winter barley, and we never have an early enough entry for oilseed rape.

"The spring barley harvest is getting later and later, and if the straw isn't baled it really holds us back with ploughing and then sowing. We can now sow oilseed rape as low as 1.8kg/ha whereas before it would be between 3.5kg to 4kg/ha when doing conventional sowing. It really saves time doing min-till, as with ploughing it could take three days to plough and sow a field," added Stewart, who also pointed out that they've managed to reduce labour and fuel costs too.

Although now purely using the Sumo Trio, the Russells are still subsoiling down 12 to 13 inches so the soil is still being broken. There's also fewer plants per square metre so they find the crops tiller better.

Finlay added: "The biggest benefit is the soil structure, as the soil is regenerated which puts body back into it. The downside, however, is the slugs and I find some years that what we save on ploughing costs, we spend on chemicals to try and stop the spring barley coming back in the crops."

Despite that, the Russells have found a 10-15% increase in yields with the min-till crops, compared to conventional crops and comment that the soil structure drastically improved in just the first year.