This document specifies two methods (method A and method B) of measuring the effect of the addition of any material claimed to have a liming effect on the soil, using the same basic principles. Method A measures the changes to the soil pH resulting from the addition of any material claimed to have a liming effect on a standard soil, measured over a period of one month. Method B assesses the efficiency of any material claimed to have a liming effect, using a range of defined soils and measured over a period of up to 2,5 years. NOTE These methods allow comparison of products under controlled climatic conditions but do not replace field experiments. The methods are not applicable to mineral products coarser than 6,3 mm for method A or 20 mm for method B.