WAYS of alleviating soil compaction in grassland were among issues discussed at an event organised by the Campaign for the Farmed Environment (CFE) near Darlington on Tuesday (16).

Mike Burley of Opico said that problems with compaction in grassland were generally caused by rain and surface water, as well as by livestock or machinery travelling over the land.

The main non-inversion options were to use a sward slitter, which would cost around £4,450, or a sward lifter, at around £11,000. The first step towards finding out which option would best suit the farm was to dig a hole with a spade, to assess the extent of the damage, he said.

“If it is obvious that compaction is confined to the top 15cms (six inches) of the soil, then a sward slitter should do the job effectively,” he told the meeting at Acorn Dairy, Archdeacon Newton.

“Anything below that figure will normally require a sward lifter. Soil type is also relevant; a sward lifter is usually associated with heavy clay, while the slitter may perform adequately on sandier soils.

“There is a significant price difference between the two machines, but it is false economy to choose the cheaper method, if it is not capable of enhancing the soil structure. A field in which water drains away easily and where plant roots have access to oxygen in the soil will be more productive. Livestock will be able to stay out longer at either end of the season, with the potential for considerable savings on feed costs.”

The best time to use either a sward slitter or a sward lifter was either in early spring, or in the autumn, he added. The land should be dry enough to travel, without causing further structural damage.

Mr Burley said Opico had used Guttler rollers on its sward lifter, rather than standard steel rollers. Their prism design exerts downward and sideward pressure, creating fissures in the soil and followed the contours of the land. The rings remained in the top layer of the sward, without sinking deeper in places. Meanwhile, the Opico sward slitter blades had a chamfered edge, which left a clean cut through the sward, with no tearing.

The use of a heavy roller on grassland was not always beneficial, he said.

“The rolling of grassland is carried out for several reasons; to stimulate root structure, promote tillering, to bury stones and to flatten molehills, in order to prevent silage contamination. Rolling can also help to repair frost damage and this is the only situation where I would recommend a heavy roller.

“A lot depends on individual field circumstances, but in most cases, a Cambridge roller with breaker rings will produce better results. There is no point in spending money on relieving soil compaction, only to reverse the effect by using a heavy rolling technique,” said Mr Burley.

o The CFE is a joint project made up of a number of industry organisations, including the NFU, CLA, DEFRA, the Environment Agency and the RSPB.