Subordinate horizon

To provide even more information about a soil, subordinate horizon designations are used. These are modifiers of the master horizons that... 

Table 8-3 Master soil horizons and some common subordinate horizon designations"...

Fig. 4.21 Idealized soil profile showing master soil horizons and horizon abbreviations. The 0, A, E and B master horizons can be further subdivided into subordinate horizons depending on composition (see Figs 4.23M-.25). Note that the O horizon is composed of fresh (L) and partially decomposed (F) organic litter. Soil profiles are typically 0.5-1.0m thick such that master horizons are typically centimetres to tens of centimetres thick. SOM, soil organic matter CEC, cation exchange capacity.

List three major horizon designations and three subordination designations and explain what they reveal about the horizon. 

Table 2(b) Definitions used to identify the subordinate characteristics of soil horizons. 

In a higher phase of communist society, after the enslaving subordination of the individual to the division of labour, and therewith also the antithesis between mental and physical labour, has vanished after labour has become not only a means to life, but life s prime want after the productive forces have also increased with the alt-round development of the individual, and all the springs of cooperative wealth How more abundantly - only then can the narrow horizon of bourgeois right be crossed in its entirety, and society inscribe on its banners from each according to his ability, to each according to his needs. ... 

Transitional horizons are layers of the soil between two master horizons. The designation uses the capital letters of the two master horizons the first letter indicates the dominant master horizon characteristics while the second letter indicated the subordinate characteristics. For instance, an AB horizon indicates a transitional horizon between the A and B horizon, but one that is more like the A horizon than the B horizon. An AB or BA designation can be used as a surface horizon if the master A horizon is believed to have been removed by erosion. The separate components of two master horizons are recognizable in the horizon and at least one of the component materials is surrounded by the others. The designation is by two capital letters with a slash between them. The first letter designates the material of greatest volume in the transitional horizon. For example A/B, B/A, E/B or B/E. 

According to Kundler, migration of fine clay (<0.2 fim) into the B horizon is the main factor determining mica distribution in a typical loessial soil, whereas clay formation by disintegration of coarser fractions and dissolution of clay minerals play only a subordinate role. The portion of mica, as calculated from the potassium content, amounts to 43 to 50 % in the fine clay and to 54 to 58 % in the coarse clay, expandable minerals amounted to 44 to 45 % and 10 to 11 % in the fine and in the coarse clay, respectively. Thus, by the selective migration of fine clay, the absolute mica content is increased in the B horizon, but the portion of mica in the total clay fraction ( < 2 / m) is lowered (Figure 5). 

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