The Agricultural Lime Association has produced guidelines to help farmers get value for money and the correct product for their soil type.

Growers should know the specification of the product and not accept agricultural lime as a legal definition, it says.

If there is no specification, analysis or datasheet, then growers should question the suitability of the product, the association adds.

Furthermore, the higher the neutralising value the better the product.

On fineness of grinding aim for 95% passing through a 3.35mm sieve and 30% through a 150micron sieve, for immediate efficacy.

Farmers should also check how much of the product is calcium, and how much is inert silicas.

The latter can range from 1-2% up to 20-30%. When comparing products, divide the price by the NV to get the unit cost, and examine the percentage passing 150 microns.

The latter should be 40%.