- Regarding A1 and B2 horizons, the EC of both topsoil and subsoil is in the "0-0.63 dS/m" class .
- As O.M % topsoil is less than 2.5, the class "0-2.5" is selected and for subsoil acidity, pH=7 is entered.
- Soil structure is moderate and the solum contains mottling (up to 30 %).
- For the subsoil clay %, the value 45 is entered (Fig. 5.6) and for the A2 (E) horizon "sporadically bleached A2" horizon is selected.
- The above soil profile description shows no concretions , hardpan, gypsum, topsoil and subsoil calcium carbonate or an alluvial layer, so "Next" is selected in each case.
- The soil has a pedological subsoil in that there is a well-developed B2 horizon.
- As the soil is presumably formed from sandstone, "Other" is selected for parent material.
- The moist subsoil colour is 5YR 4/8 and 5YR for hue, 4 for value and 8 for chroma should be entered before selecting "OK".
- Table 1 gives a summary of all the above attributes and their classes.
- After a short time membership to one or more of the GSG will be displayed as shown in Figure 3.
- After entering the required initial information, clicking on "Next" gives the Soil Data display.
- The texture profile is uniform and as the topsoil and subsoil are highly saline, the salinity class ">2.5 dS/m" should be selected.
- The class 10-30 % CaCO3 for topsoil and subsoil calcium carbonate and for O.M. the class less than 2.5 % should be chosen.
- Soil structure is moderate and the soil profile contains some concretions as well as some gypsum and a crust exists on the surface.
- There are no mottles, A2 horizon, hardpan or an alluvial layer.
- Clay content is 35 % and the subsoil colour is 7.5YR 5/4.
- Table 5.2 gives a summary of the soil attributes and their classes.
Example Using ASIS
An example from Australia: a step-by-step guide
The following soil description is of a profile from the Lower Namoi Valley in New South Wales, Australia, (McGarry et al., 1989). The soil has a texture contrast and is formed on alluvial sediment and clay deposits.
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Dark brown (7.5YR 3/2); sandy loam; massive; pH=7; EC=0.08 dS/m; OM%=2.2; clay%=9; | |
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Dark brown (7.5YR 4/4); sandy loam; massive; sporadically bleached; pH=7.2; EC=0.06 dS/m; OM%=1; clay%=11; | |
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Yellowish red (5YR 4/8); light clay; moderate columnar structure; pH=7; EC=0.07 dS/m; OM%=1; clay%=45; | |
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Reddish brown (5YR 5/4); medium mottles; weak columnar structure; few medium calcareous nodules; pH=7.7; EC=0.3 dS/m; OM%=0.7; clay%=29. | |
To allocate this profile to a GSG using ASIS, select from main menu dialog box (Fig. 1) "Soilwizard" or "Enter Attributes". Soilwizard is a step-by-step data entry procedure with each step explained. "Enter Attributes" is for more experienced users. In this example, as an inexpert user, the "Soilwizard" is selected. A selection of dialog boxes are presented in this step-by-step
example. The initial entry is for the soil describer and identifier’s name along with the profile location (Fig. 2). By clicking on "Next" the texture type dialog box appears (Fig. 5.3). As the soil is not organic, "Other" and "Next" are selected.
Originally, this soil example was allocated to the GSG class of red-
brown earth but in the fuzzy classification it has partial membership in
different groups of which the three main ones are: Red Podzolic Soil (0.42),
Red-Brown Earth (0.38) and Non-Calcic Brown Soil (0.08).
Table 1. Soil attributes and their classes for soil example 1
| Soil Membership based on attributes | |
| Describer: | nr240995 |
| Sample Identifier: | p1 |
| Sample Location: | Narrabri |
| Comments: | Sample from cotton crop taken on the 24/9/95. |
| Information given: | |
| Texture Profile: | Gradational |
| Topsoil Salinity: | >2.5 dS/m |
| Subsoil Salinity: | >2.5 dS/m |
| Topsoil Organic Matter: | >2.5 - 10% |
| Subsoil pH: | 8.8 |
| Subsoil structure: | Weak |
| Mottling Solum: | Up to 30% mottling by area covered |
| Clay percentage: | 55 |
| A2 Horizon: | Absent |
| Concretion Solum: | No concretions |
| Crust: | Present |
| Hardpan: | Absent |
| Topsoil Calcium Carbonate: | None |
| Subsoil Calcium Carbonate: | None |
| Gypsum: | Present |
| Pedological Subsoil: | Absent |
| Aluvial Layer: | Absent |
| Parent material: | Others |
| Colour: | 10yr 6/2 |
| Soil Group | Membership (0.00 - 1.00) |
| Extragrade | 0.892 |
| Coastal Solonchak | 0.097 |
An example from the USA
This soil is from Reeves County, Texas (refer to 4.4.6), USA (Soil Taxonomy, 1975) and is formed from calcareous, gypsiferous alluvium on a level plain with the following description.|
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Brown (10YR 4.5/3); loam; platy crust; slightly hard (dry), very friable (moist); strongly effervescent with acid |
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Brown (10YR 4.5/3); loam; moderate medium platy structure; slightly hard (dry); very friable (moist); strongly effervescent; |
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Brown (10YR 4.5/3); loam; weak to moderate fine subangular blocky structure; hard; friable; strongly effervescent; |
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Light brown (7.5YR 5/4); clay loam; weak to moderate fine subangular blocky structure; hard; friable; strongly effervescent with few concretions, films and threads of calcium carbonate; |
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Light brown (7.5YR 5/4); clay loam; weak fine subangular blocky; consistence; reaction and calcium carbonate as above; |
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Very pale brown (10YR 8/3); weakly cemented gypsiferous calcareous loam; very hard (dry); friable and somewhat brittle. |
On the supposition that users are acquainted with the definitions and explanations, the above soil profile will be allocated to the GSG system using the alternative means of data entry, "Enter Attributes".
The soil was allocated to the class of Gypsiorthid in Soil Taxonomy and to the fuzzy classification as an Extragrade (0.61). This example shows how the system works with soil not common in Australia. There are great dissimilarities between the GSG centroids and this soil which has considerable membership in the extragrade group. The remaining small membership is distributed among various GSG like Arid Solonchak, Rendzina, Red Earth and Krasnozem.
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