It is important that you know the liming value of the product that you are using. In the Outer Isles it is common to use sand. However the different sands have different neutralising values and it is important that you know this for accurate and effective liming.
If you use the liming calculator below you can see the effect that the differences in neutralising value has. For example a field that the liming recommendation was to apply 5t/Ha of lime. If you were using Barvas sand (26.4% neutralising value) you would need to apply 9.5t/Ha of sand. However if you were using Eorpoie sand (34% neutralizing value) you would only need to apply 7.5 t/Ha of sand.
The calculator also warns you if the lime needs to be applied as a split dressing, with at least 6 months apart.
Where products are similar in fineness they can be compared on the basis of cost per unit of neutralising value (%CaO). The cost of a unit of neutralising value is equal to the cost per tonne of lime (including delivery and spreading) divided by the neutralising value (%CaO).
So for example if the liming products are the same price but neutralising values are the same, as in the example above of, 48% and 38% then the neutralising values are as below.
£20/t/48 = 0.42
£20/t/38 = 0.52
The higher neutralising product is better value for money.
For further information see the following technical note for guidance: TN656 Liming and soil texture
If you have any questions about soil liming or for further advice, visit our advice and grants page for details of our helpline who will be able to give you bespoke advice to support you and your business.
Sign up to the FAS newsletter
Receive updates on news, events and publications from Scotland’s Farm Advisory Service