Base-neutralizing capacity of Finnish mineral soils

The base-neutralizing capacity, BMC7 (OH- as meq kg-1 needed to raise soil pH to 7), was determined graphically from curves obtained in KOH titration (at a constant ionic strength of I = 0.1). In 84 soil samples, BMC7 amounted to 0—316 meq kg-1, being highest in the heavy clay soils and lowest in the non-clay soils. In different textural groups, BMC7 seemed most markedly to be dependent on the initial soil pH, followed by organic C or oxalate soluble Al, in the coarser clays also on clay content. The results evidence that in determination of lime requirement, attention should be paid to the capacity of soil acidity. In routine soil testing, detailed lime recommendations for various soil types are needed