Neutralising value (NV)
The key indicators of agricultural lime quality are neutralising value and particle size, regardless of the source.
The carbonate content of limesand, limestone or dolomitic lime determines the capacity of the lime to neutralise acidity. Neutralising value is expressed as a percentage relative to pure calcium carbonate, which is given a value of 100%. With higher neutralising value, lime can be spread over a greater area, or less tonnes per hectare (t/ha) used, for the same pH change (Figure 2).
Agricultural lime suppliers should provide results of current laboratory tests detailing the neutralising value (sometimes expressed as NV) of the various particle sizes in their product. These values can be used to calculate the best value lime available.
