8 September 2001

How do I apply lo-till to the whole rotation?

From barley to beet, pulses to potatoes – crop type doesnt appear to be a limitation when it comes to lo-tilling, reports Debbie Beaton

ONCE you have made the decision to ditch the plough, its a question of how to make minimal tillage work across your rotation without it. And the Game Conservancy Trusts Alastair Leake, who has been a min till exponent for several years knows better than most.

He has successfully min tilled just about everything – even potatoes: "We turned to min tilling an organic salad potato crop because of a wild oat problem," he explains. The plough system was creating a wild oat problem, by bringing buried seeds to the surface. With no chemicals at his disposal to the control the weed, because it was an organic crop, he switched to min tillage.

He chose to plant a cover crop of vetch, which is easier to control than clover, to build fertility and in the spring this was chisel ploughed and disced to make the tilth. "The chisel plough went down to 8in, but we did not invert the soil. The surface was then disced, power harrowed and then ridged." Admittedly it was a salad crop so it may not have needed the depth of tilth required for a ware crop, but all the same he was pretty happy with the results.

Min tilling after grass was a little more tricky, he recalls: "Taking three cuts of silage produced a fair bit of compaction which we had to rectify. So we chose a Tim Howard subsoiler, which opened up the surface but did not pull blocks of soil up to the top. Then we ran a set of rolls over the top to close up the tracks and direct drilled."

Burn off

Spraying with glyphosate was obviously crucial to grassweed control in both situations. The gap between harvesting and drilling must be wide enough to ensure weed germination and a good burn off.

The sooner you can go in after the combine, the better he says: "We have followed the combine straight away and already grassweeds are chitting to give us a good burn off," says Mr Leake.

Ploughing presents worse time pressures, he adds: "When you min till you nearly have a seedbed. When you plough you are still miles away from creating a seedbed."

So if you can min till potatoes and min till after grass, surely anything is possible? On combinable crops most experts agree that lo-tilling is straightforward on all but the lightest soils, which have no natural self-structure and a tendency to slump.

For some crops there will be a need for deeper soil work in the autumn, points out ProCams Nick Myers. "Spring crops, for example, need to get their roots down quickly and will therefore need a more well-structured soil," he says.

Some of his clients have successfully direct drilled spring beans, using minimal cultivations in the autumn: "Pulling a deep tine through the soil in the autumn and allowing it to weather over the winter, followed by direct drilling in the spring has been successful. You could probably get away with it on peas too – as long as there is no obstruction for rooting," adds Mr Myers.

What about sugar beet? British Sugar have two trials in Suffolk and Lincs to compare a plough-based system to min tilling. Results have been encouraging and there are a handful of farmers who have been very successful, including Peter White at Kneeshall near Newark.

He was an early convert to Eco-till for his wheat, barley and rape. Seeing the benefits to soil structure on his difficult capping-prone, silty, clay loams inspired the move to sugar beet – along with potential savings in establishment costs.

British Sugar has also been looking at min tillage and is now persuaded that non-ploughing can work on a range of soil types for sugar beet. In two years of trials, a disc-based system has worked well, reducing establishment costs, producing better soil structure and lessening soil erosion.

This year British Sugar has been trialling the Aqueel, a roll or packer, developed by farmer Charles Creyke and sold by Simba. The Aqueel leaves dimples, with dams in between which hold water and therefore prevent soil water run off and also protect against blowing. The machine has followed a Flatlift subsoiler, put through at a depth of 14in, a day or so prior to drilling in the British Sugar trials.

In these trials though, good straw management has proved crucial. A fact that Paul Sheardown, who has been direct drilling in the Vale of Belvoir for the past five years can testify.

It is one of the guiding principles – along with compaction and grassweed control – that are crucial to any min till or direct drilled system, he says. Much to his disappointment – and outside his control – two of those principles have come unstuck this year.

He has direct drilled 380ha of wheat and oilseed rape on heavy clay loams in the Vale of Belvoir for nearly 10 years. His establishment strategy has been harvest, spray off and sow into the trash with a Kuhn direct drill for the past five of those years.

It has worked well – until now. Unfortunately, slugs and compaction are forcing a rethink on straw incorporation and soil disturbance. He has been a strong advocate of not disturbing the soil and allowing it to remain in its natural state. But a slug problem that he admits he is "constantly chasing" is forcing him to incorporate straw trash for the first time in five years.

"The straw sits on the surface from one year to the next – it just stays there and doesnt break down providing the perfect environment for slugs. So, reluctantly, I have to try and get rid of it. I am convinced that by not disturbing the soil we are encouraging the slugs," he says. Its a problem which has been costing him at least three applications of pellets each season; half dose of mini-pellets prior to drilling, half dose immediately after drilling and then again 10 days later.

Compaction

By creating a fine tilth, he hopes to smash the eggs and fill in the fissures where the young emerge. Its a move away from direct drilling towards minimal tillage: "We are only moving the top two inches. So immediately after harvesting oilseed rape I have gone through with a set of discs set very shallow. Once there is a good weed germination, we will skim over with a power harrow and roll down with set of cambridge rolls, spray off and drill," he says.

Compaction has also been a big blow. "We have gone to extremes to be kind to the soil by using wide tyres and keeping traffic to a minimum. So it is all the more galling to find that the weather washed away all our efforts this year," he says.

July proved to be the wettest month on the farm, with more than 170mm falling on one day, creating compaction that he is now having to rectify with sub-soiling and mole drainage. It was the final punch in a season that has battered his crops to submission, with yields on both wheat and rape down by 30%.

But he is not going to be beaten by what he believes has been a freak season. He remains committed to lo-tilling and this autumn is tweaking the rotation to include 20ha of second wheats for the first time. Meanwhile it is business as usual with the Kuhn drill – partnered with a set of discs for those slugs.