New and improved seed drills for sowing direct into stubbles were much in evidence at this year’s Lamma show in response to increasing enthusiasm for the technique among growers.

Increased seasonal capacity for a single tractor and driver, reduced establishment costs and improved soil structure over time are among the appealing factors.

So, too, is the technique’s ability to cope with variations in conditions by conserving moisture in a dry sowing season and simply getting crops in during a wet year.

“On our heavy clay farm in Suffolk, we used one of our 6m Hybrid drills to sow 1,200ha of cereals by the end of September last year in 150 tractor hours,” notes Spencer Claydon. “It then went on to drill a total of 3,700ha in around 500 hours.”

The lack of discs, packers and land wheels on this mounted seeder helps in wet, sticky conditions, he emphasises. But the strip tillage technique itself also helps by cultivating only where necessary while leaving firm stubble ground in between to support the tractor.

Since 2006, when Mr Claydon’s business started co-operating with Saaten Union to compare plough-based and strip tillage techniques using 16 of the German breeder’s winter wheat varieties, the one-pass system has clocked up a 10% lead in yields, with plough-based establishment coming top only once in that period.

“In that time we’ve had very wet drilling seasons in 2009 and 2010, an extremely wet period in 2012, and a very dry sowing season in 2011,” notes Mr Claydon. “Yields from strip tillage using the Claydon system were ahead in all cases and by the biggest margin in the dry year.”

A twin-tine kit was rapidly developed last autumn to replace the single A-blade band-sowing coulter in very challenging soil conditions. They each place seed in a 30mm band either side of the deeper slot formed by the leading tine, which provides drainage and an opportunity for deep root growth.

The narrow profile of the tines means they work in wet, heavy soils without smearing or pulling up clods and should prove useful for establishing spring crops without costly cultivations. Kits are available for equipping existing Claydon Hybrid drills.Mzuri’s Martin Lole also emphasises the timeliness advantages of drilling direct into stubbles and the disadvantages of loosening soil before drilling when conditions turn sour as they did last autumn.

“With no pre-cultivations exposing the land to the vagaries of the weather, fields remain more accessible,” he points out. “Besides, with the high work rates available, there is a greater chance of getting crops sown before deteriorating weather moves in.”

The principles of strip tillage, he underlines, are to leave chopped straw on the surface where it provides a barrier to moisture evaporation while encouraging worm activity, and to leave stubbles long so they guard against capping and erosion.

“We then like to create a clean strip of moist soil by using a disc to move straw to one side so there is no risk of nitrogen being locked up in the vicinity of young plants,” Mr Lole says. “We then cultivate the strip using a tine ahead of the double-shot band sowing coulter, and reconsolidate afterwards for good seed-to-soil contact.”

A new mounted seeder, the Mzuri Zip-Til, is designed to be lighter, easier to pull and have better trash clearance than the existing 3m mounted Pro-Til. It lacks the press wheels and tyres installed ahead of the coulters and has increased coulter assembly stagger.

Power requirement is reckoned to be around 50hp/m instead of 60-70hp/m and the Zip-Til comes in 4m and 4.8m sizes in addition to 3m. All have auto-reset tines and coulters, individual seed metering and laser monitoring for each row, and a 1,250-litre steel hopper.

Sumo has taken a similar soil-working route with its first strip till drill. The Deep Tillage Seeder (DTS) has a leading disc to cut through trash, an auto-reset tine working to 350mm with a 150mm band sowing coulter close behind, twin covering discs and a pneumatic press wheel.

The individual coulter assemblies spaced at 333mm centres are free to follow surface contours and are held in work by hydraulic constant pressure springing. Sumo plans eight sizes from 3-12m.

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New drill will help push strip-till concept