New Chemical Criteria for Defining the Spodic Horizon1
- D. L. Mokma2
Many soils which morphologically appear to be Spodosols do not meet the chemical requirements for the spodic horizon. The purpose of this study was to develop new chemical criteria for defining the spodic horizon. New chemical criteria were developed using samples from 18 pedons and were further tested with samples from 28 soil monoliths. The proposed criteria for the spodic horizon are: (i) more Cp + Alp + Fep than the overlying E horizon or A horizon if the E horizon is absent; (ii) Cp + Alp + Fep ≥ 0.50%; (iii) Cp/ (Alp + Fep) atomic ratio is 5.8 to 25.0; and (iv) illuviation index ≥ 5.0 for subhorizons with 1, 2, and 3. All 32 pedons or monoliths with Spodosol morphology met the new chemical criteria. All 11 pedons or monoliths with nonSpodosol morphology failed to meet the criteria. One of the three monoliths with weak Spodosol morphology met the new criteria.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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