PRESENTATION OF THE SRCL2-METHOD AFTER BA CH FOR THE DETERMINATION OFTHE EFFECTIVE CATION-EXCHANGE CAPACITY AND COMPARISON WITH THE NH4CL-METHOD

The SrCl2-method for the determination of the effective cation exchang e capacity CEC(eff) has been developed by Dr. H. Bach, a former geoche mist of the ''Geologisches Landesamt Schleswig-Holstein''. Exchangeabl e metallic cations in soils are displaced by a 0,1 M SrCl2-solution an d analyzed from the percolate. Reexchange of strontium by a 0,1 M MgCl 2-solution allows to determine the CEC(eff) by analyzing for strontium in the second percolate. In comparison with the customary application of NH4Cl, SrCl2 shows the following advantages: 1. The nearly unbuffe red SrCl2-solution adopts instantly the pH of the soil. 2. In contrast to the weakly acid NH4Cl-solution, no H3O+-cations compete with the e xchange cation. Furthermore, partial dissolution of clay minerals is p revented because of the near-neutral character of the SrCl2-solution. 3. The SrCl2-method can be applied on all types of soils including car bonate- and salt-bearing soils. 4. The amount of free (dissolved) cati ons can be approximated.