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SOIL SURVEY

SOIL SURVEY

SOIL SURVEY

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-24-According to Kuchar (1976) the separation could be made quite distinctly usin gfloristic criteria . Plants such as golden fleabane, alpine sandwort, black alpin esedges and western anemone were very rare in the subalpine zone whereas stickseeds ,cow parsnip and meadow rue did not occur in the alpine zone .The foregoing discussion provides an introduction to the vegetation withi nYoho; further observations can be found in the discussion of the map unit descriptions .<strong>SOIL</strong> FORMATIO NSoil Forming FactorsThe soil-forming factors of climate, living organisms, topography, natureof the parent material and time (Brady 1974) all contribute to the genesis of everysoil (Figure 11) . The relative importance of each factor differs from place to place ;sometimes one is more important, sometimes another . Detailed discussions of thesoil-forming factors and their interactions can be found in Buol et al . (1973) .L F HOrganic horizon, which may he subdivided into : L (raw organicmatter) . F (partially decomposed organic matter), and H (decomposedorganic matter) .A mineral horizon at or near the surface . It may he a dark-coloredA horizon in which there is an accumulation of humus (Ah) . or alight-colored horizon from which clay, iron, and humus have bee nleached (Ac) .AB Transition horizon .Mineral horizons that (I) may have an enrichment ol' clay (Bt) . iro n(Bf) . or organic matter (Bh) : or (2) may he characterized by acolumnar structure and a significant amount of exchangeahle so -B diem (Bn) : or (3) may be altered to give a change in color o rstructure (Bm) . Usually lime and salts have been leached out of thi shorizon . (4) The symbol (j) is used with the above suffixes to denot ea failure to meet the specified limits of the suffix .BC 'transition horizon .CMineral horizon comparatively unaffected by the soil-formin gprocess operative in the A and B horizons except for the process o fgleying (CO and the accumulation of calcium and/or magnesiu mcarbonates (Ck) and soluble salts (Cs) .Figure 11 . Schematic diagram of a soil profile showing various horizons . Some profilesmay not have all these horizons clearly developed . Where it is necessaryto subdivide a horizon, digits are used; for example, the Bf horizon may besubdivided into Bfl, Bf2, etc .

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