17 November 1995

Fresh lime trials urgently needed

LIME is a key agricultural input too often underrated by farmers. Poor advice and lack of education are to blame.

So says John Tunaley, an agronomist based at Stowmarket, Suffolk. "Lime is one of the most fundamental inputs. I estimate more sub-optimal yields are the result of soil acidity than any other factor."

He believes arable soils should be maintained at or near neutral. "We are battling in the east against the old mentality of 2t/acre will do. But in todays high input/high output systems soils need to be at pH7 for optimum fertility."

That stimulates microbe and earthworm activity, and improves soil structure, he explains. Better crops, less disease and better herbicide activity result. Crops respond better to other inputs, he adds.

But the Agricultural Lime Producers Council are failing to get the message across, says Mr Tunaley. Outdated, "stale" information does not help. "Its 30-40 years old. There is a failure to generate new information."

Lime producers need to approach research bodies to establish "up to the minute" trials. "The HGCA has no trials in progress and none are planned. Morley and ARC are doing nothing. Approach these people or do your own trials," he urges.

Farmers also receive "conflicting advice" on products, says Mr Tunaley. Neutralising value, water content, physical properties and sieve sizes vary widely. "Farmers dont understand what is good and bad. In future I shall try to help them understand the parameters of quality. But I shouldnt need to. The industry could do it."

Mr Tunaley suggests the ALPC should agree on a liming effectiveness index, perhaps using a star rating scheme. "Until the industry improves, it will leave doubt in farmers minds."

Regular sampling should replace the "fire-brigade" approach, he believes. Better pH measurements would help too. These do not reflect field conditions – acidity rises as soils dry, but tests do not show this, says Mr Tunaley. "Slurrying soils increases pH by 0.5. Grinding them raises it further. I have countless examples which show this."

&#8226 Chairman of the ALPC Bob Gagg admits his members need to increase farmer confidence. But he points out that finances are limiting. "We have to rely on contributions from members. That only stretches so far."

But a three-year programme, partly funded by the ALPC and the Fertiliser Manufacturers Association, "due to start shortly", will help address some problems, he says. &#42


&#8226 Key input, underrated.

&#8226 Arable soils need pH7.

&#8226 Outdated information.

&#8226 Trials needed.

&#8226 Annual check-ups urged.

&#8226 Three-year study to improve sampling and testing planned.

Lime advice is out of date and poorly communicated, says adviser John Tunaley. The ALPC is funding new work in a bid to rectify the matter.