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Chapter 2




              Key to the


              Reference Soil



              Groups








              Table 4      Simplified guide to the WRB Reference Soil Groups (RSGs)
                           with suggested codes.


                               Key to the Reference Soil Groups                        RSG          Code

               1. Soils with thick organic layers:

               Soils which are composed of organic materials                      Histosols           HS
               2. Soils with strong human influence

               With long and intensive agricultural use:                          Anthrosols**        AT

               Containing significant amounts of artefacts:                       Technosols*         TC

               3. Soils with limitations to root growth
               Permafrost-affected:                                               Cryosols**          CR

               Shallow or with many coarse fragments:                             Leptosols           LP

               With a high content of exchangeable Na:                            Solonetz            SN

               Alternating wet-dry conditions, shrink-swell clays:                Vertisols           VR

               High concentration of soluble salts:                               Solonchaks          SC

               4. Soils distinguished by Fe/Al chemistry
               Groundwater-affected, underwater and in tidal areas:               Gleysols            GL

               Allophanes or Al-humus complexes:                                  Andosols**         AN

               Subsoil accumulation of humus and/or oxides:                       Podzols            PZ

               Accumulation and redistribution of Fe:                             Plinthosols         PT
               Low-activity clay, P fixation, many Fe oxides, strongly structured:  Nitisols*        NT

               Dominance of kaolinite and oxides:                                 Ferralsols          FR

               Stagnating water, abrupt textural difference:                      Planosols*          PL

               Stagnating water, structural difference and/or moderate textural difference: Stagnosols*  ST


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