This publication encourages the use of detailed soil maps in solving waste-disposal problems in Kansas, in conjunction with other studies. Soil landscapes, soil maps, and soil-profile descriptions of parts of Kansas are briefly explained. Relevant research and soil classification is summarized in narrative and tabular form. Criteria for rating Kansas soils as having slight, moderate, or severe limitations for septic-tank seepage fields, sewage lagoons, and trench-type and area-type sanitary landfills are given, and ratings are made for each of the 300 or so soil series of Kansas. Use of detailed soil information is explained, and references and terms are given for further consultations. Soil maps should be considered to be a first approximation to solution of land use problems; they are most useful when combined with deeper geologic investigations and other complimentary studies.
These definitions are for laymen--including geologists, planners, public health officials, and engineers--who may be unfamiliar with some of the terms of soil science. A 27-page glossary of soil science terms, published in 1970, is available from the Soil Science Society of America, 677 South Segoe Road, Madison, Wisconsin 53711, for those who want a more complete listing. A publication (Olson, in press) in the reference list is specially designed to explain exact criteria for interpreting the terms of a soil-profile description. Interpretation of soil-profile descriptions will become increasingly important as more people use soil maps and soil descriptions for waste disposal and many other purposes.Aerobic--Aerobic conditions of an environment are those with plenty of oxygen or air for respiration and oxidation. Open sewage lagoons are aerobic systems, especially if the water is aerated (mixed). Anaerobic conditions, as in closed septic tanks, are those where oxygen content is deficient. Different sets of organisms decompose materials in the contrasting environments.
Alluvium--Alluvium is soil material deposited by floodwaters. It is stratified in places, and occupies floodplains of Kansas like those illustrated in Figures 4 and 6.
Calcareous-Calcareous soil contains sufficient calcium carbonate (often with magnesium carbonate) to effervesce visibly when treated with cold 0.1N hydrochloric acid. Kansas soils listed as carbonatic in Table 1 have more than 40 percent by weight carbonates (expressed as CaCO3) plus gypsum, and the carbonates are greater than 65 percent of the sum of carbonates and gypsum.
Colluvium--Colluvium is a deposit of soil material accumulated at the base of steep slopes as a result of gravitational action. Figure 3 shows the relative landscape position of colluvium in Brown County.
Consistence--Soil consistence is the resistance to deformation or rupture and the degree of cohesion or adhesion of the soil mass. Terms used for describing consistence at various soil moisture contents are: nonsticky, slightly sticky, sticky, very sticky, nonplastic, slightly plastic, plastic, very plastic (wet soil); loose, very friable, friable, firm, very firm, extremely firm (moist soil); loose, soft, slightly hard, hard, very hard, extremely hard (dry soil). Exact definitions of these terms are given in the publication by Olson (in press).
Effluent--Effluent is the liquid portion of sewage, especially that handled in septic-tank seepage fields. Limitations of soils of Kansas for disposing of effluent in septic-tank seepage fields are given in Table 2 and Table 6.
Eutrophic-Eutrophic conditions are environmental conditions where concentrations of nutrients are optimal or nearly so for plant or animal growth. Eutrophic conditions in lakes and reservoirs cause growth of weeds and algae, especially when sewage or waste leachates and effluents empty into bodies of water. Good waste management in soils of Kansas can help to avoid or reduce eutrophication of lakes and reservoirs, by preventing excessive nutrient enrichment of the waters.
Friable--See definition of consistence.
Glacial Till--Glacial till is unstratified glacial deposits left by the icemass and consisting of clay, sand, gravel, and boulders intermingled in variable proportions. Only the northeast corner of Kansas has soils formed in glacial till.
Ground Water--Ground water is that portion of the total precipitation which at any particular time is either passing through or standing in the soil and the underlying strata and is free to move under the influence of gravity. Depths to fluctuating ground water or apparent water table in soils of Kansas are given in Table 1.
Interstices--Interstices are the spaces between soil particles, also called pore spaces. Generally they are filled with water or air, and are the scene of most of the biological and chemical activities which are important to ultimate waste disposal and treatment in septic-tank seepage fields and sanitary landfills. The size and shape of interstices in soils are largely determined by particle size (Table 1) and other characteristics of the soil profile (Olson, in press).
Leachate--Leachate is the liquid material sometimes lost from a sanitary landfill, particularly when the landfill is improperly maintained in soils with severe limitations. Liquid material in a septic-tank seepage field is generally called effluent. Both leachates and effluents in soils with slight limitations for waste disposal (Table 6) are generally adequately filtered before reaching the water table, if the waste disposal system is properly maintained.
Loess--Loess is soil material transported and deposited by wind; it consists predominantly of silt-sized particles. Many soils in Kansas have formed in loess deposits (see Figures 3-6).
Mineralogy--Soil mineralogy is the study and characterization of natural inorganic compounds with definite physical, chemical, and crystalline properties (within the limits of isomorphism), that occur in the soil. The mineralogy of soils of Kansas is listed for each specific soil in Table 1.
Moderate Limitations--Moderate limitations are the ratings given to soils that have properties moderately favorable for waste disposal. Moderate limitations can be overcome or modified by special planning, design, or maintenance. During some part of the year moderate soils are less desirable for waste disposal than soils rated slight. Some soils rated moderate for waste disposal require special drainage, extended tile lines, extra excavation, or some other modification. Criteria for moderate limitations for soils for waste disposal are given in Tables 2, 3, 4, and 5; specific soils of Kansas with moderate limitations for waste disposal are listed in Table 6.
Montmorillonite--Montmorillonite is an aluminosilicate clay mineral with a 2:1 expanding crystal structure (with two silicon tetrahedral layers enclosing an aluminum octahedral layer). Considerable expansion may be caused along the C axis by water moving between silica layers of contiguous units. Kansas soils with high content of montmorillonite clays are listed in Table 1; these soils shrink appreciably when dry and swell when wet. This shrinking and swelling has great implications for waste disposal, affecting permeability, tile lines, trafficability, and many other aspects of soil behavior.
Mottles--Soil mottles are spots or blotches of different color or shades of color, indicating wet conditions in Kansas soils. The pattern of mottling and the size, abundance, and color contrast of the mottles varies considerably in different soils and is specified in soil-profile descriptions. Significance of soil mottling to waste disposal in Kansas is discussed in the section on soil-profile descriptions for the Butler soils.
MPN--Most probable number (MPN) is a measurement of numbers of microorganisms in water or some other media. Often the microorganisms are too numerous and too small to be counted, so that a "most probable number" is estimated instead. For coliform bacteria (see discussion of research on soils for waste disposal) a culture medium is generally inoculated with a small amount of soil or water. After incubation, a count of the number of colonies formed on the culture medium enables a "most probable number" to be estimated to give an approximation of the number of organisms present in the original sample.
Nontronite--Nontronite is a clay mineral of montmorillonitic type with a relatively high content of iron (see definition of montmorillonite).
Particle Size--Particle size refers to the grain-size distribution of the whole soil down to a depth of about one meter or to a hard layer or bedrock. The term is a marriage between engineering and pedologic (soil science) classifications. Particle size groups of Kansas soils are given in Table 1 and Figure 12, and are discussed in the section on soil classification. Particle size groups include soils that are sandy-skeletal, loamy-skeletal, clayey- skeletal, sandy, loamy (coarse-loamy, fine-loamy, coarse-silty, fine-silty), and clayey (fine, very-fine).
Ped--A ped is a unit of soil structure such as an aggregate, crumb, prism, block, or granule, formed by natural processes. A pedologist is a person who studies peds and whole soils in their natural state.
Pedologist--See definition of ped.
Percolation Rate-Percolation rate is the rate of downward movement of water through soil. For septic-tank seepage field design it is measured commonly in auger holes in soils with minutes for the water level to drop one inch the unit of measure, indicating the downward flow of water in nearly saturated soil at hydraulic gradients of the order of 1.0 or less. Some of the variabilities of auger bole percolation tests in soils are discussed in the section on soil classification.
Permeability--Permeability is that quality of soil that permits it to transmit gases, liquids, and sewage effluent. Permeability classes (slow, moderate, rapid) are defined in the section on soil classification, and are specified for soils of Kansas in Table 1. Permeability rates (in/hr) are also compared with percolation rates (min/in) in the discussion on soil classification.
ppm--Parts per million (ppm) is a unit of measurement, generally expressed in weight of an element, nutrient, or contaminant as compared with the weight of the media or mass in which it occurs.
Rockiness--Rockiness refers to the relative proportion of bedrock exposures, either rock outcrops or patches of soil very thin over bedrock, in a soil area. The word rocky is used arbitrarily for soils having fixed rock (bedrock). In contrast, the word stony is used for soils having loose detached fragments of rock. Specific classes of rockiness are defined in the publication by Olson (in press). Rockiness classes 0 to 5 in Table 2 and Table 4 indicate increasing proportion of rock in the map units as the numbers increase.
Septic-Tank Seepage Field--A septic-tank seepage field is a system enabling filtration and oxidation of sewage liquids in soils. After sewage digestion in a septic tank, effluent seeps through the soil and is purified over time in the seepage field. Eventually, the water becomes free of health hazards and returns to the ,round water for reuse. Figures 21 and 22 are examples of the many kinds of septic-tank seepage fields.
Severe Limitations--Severe limitations are the ratings given to soils that have one or more properties unfavorable for waste disposal, such as steep slopes, bedrock near the surface, flooding hazard, high shrink-swell potential, or unfavorable permeability. This degree of limitation generally requires major soil reclamation, special design, or intensive maintenance. Some soils can be improved by reducing or removing the soil feature that limits use, but most are difficult and costly to alter for waste disposal. Criteria for severe limitations for soils for waste disposal are given in Tables 2, 3, 4, and 5; specific soils of Kansas with severe limitations for waste disposal are listed in Table 6.
Siliceous--Siliceous soils have more than 90 percent by weight of silica minerals (quartz, chalcedony, or opal) and other extremely durable minerals that are resistant to weathering. Kansas soils which are siliceous are listed in Table 1.
Slight Limitations--Slight limitations are the ratings given to soils that have properties favorable for waste disposal. The degree of limitation is minor and can be overcome easily. Good performance and low maintenance can be expected, Criteria for slight limitations for waste disposal are given in Tables 2, 3, 4, and 5; specific soils of Kansas with slight limitations for waste disposal are listed in Table 6.
Slope--Slope is soil surface deviation from the level horizontal plane, measured in percentage (units vertical drop per 100 horizontal units). Thus a slope of 15 percent has 15 feet of vertical drop for each 100 feet of horizontal distance. Slope complexities are also described in the soil survey, where soil map units have undulations or other variations from a simple slope.
Soil--Soil is unconsolidated material several feet thick formed by environmental factors acting on geologic materials over time, conditioned by relief, to produce a sequence of layers or horizons which occupy predictable and mappable parts of landscapes. Soil, as used in this Bulletin, refers to delineations on soil maps and descriptions of those soil map units with depth in the landscapes of Kansas. Soils in landscapes are illustrated in Figures 3-6.
Soil-Drainage Class--Soil-drainage class is determined by mottles and patterns of color in soils, indicating duration and extent of wet conditions. Drainage classes include excessively drained, somewhat excessively drained, well drained, moderately well drained, somewhat poorly drained, poorly drained, and very poorly drained. The classes are briefly discussed in the section on soil classification, are specified for Kansas soils in Table 1, and are more completely defined in the Soil Survey Manual (Soil Survey Staff, 1951).
Soil Map--A soil map is a map showing the distribution of different soil map units in relation to the prominent physical and cultural features in the geography of Kansas. Examples of soil maps are given in Figures 27-29.
Soil Profile--A soil profile is an exposed section of soil commonly described for each soil map unit in a soil survey. Figure 8 is an illustration of a soil profile.
Soil Series--Soil series is the basic unit of soil classification consisting of soils which are essentially alike in all major characteristics except the texture of the surface horizon. Soil series are generally named for the places where they were first identified; Table 1 and Table 6 list the soil series mapped in Kansas.
Stoniness--Stoniness refers to the number and kinds of loose coarse fragments in or on soils. Specific classes of stoniness are defined in the publication by Olson (in press). Stoniness classes 0 to 5 in Table 2 and Table 4 indicate increasing stoniness as the numbers increase.
Structure--Soil structure is the combination or arrangement of primary soil particles into secondary particles, units, or peds. These secondary units may be arranged in the profile in a distinctive characteristic pattern. The secondary units are characterized and classified on the basis of size, shape, and degree of distinctness into classes, types, and grades. Classes (size) include fine, medium, and thick; types (shape) include plates, prisms, blocks, and granules; grades (degree of distinctness) include weak, moderate, strong, and structureless. Structure examples are given in the section on soil profile descriptions for some soils of Kansas; exact definitions of the terms are in the publication by Olson (in press).
Texture--Soil texture is the relative proportion of sand (0.05-2.0 mm diameter), silt (0.002-0.05 mm diameter), and clay (less than 0.002 mm diameter) in a soil sample. Soil textures include sand, loamy sand, sandy loam, loam, silt loam, silt, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, and clay. Soil textures are precisely defined in the publication by Olson (in press).
Trafficability--Trafficability of soils is the relative ease or difficulty with which wheeled or crawler-type vehicles can move over the soils. Trafficability is a general term, dependent upon type of soil materials (see definition of unified soil classification), depth to water table, soil moisture content, slope, and many other factors. Trafficability of soils is especially critical for heavy equipment during installation of septic-tank seepage fields, construction of sewage lagoons, and covering of sanitary landfill in Kansas soils. Wet clayey soils (Figure 9) with high content of montmorillonite (listed in Table 1) generally have poor trafficability; well-drained soils with loamy textures (Table 1) on level or gentle slopes generally have good trafficability. Soil consistence (see definition of consistence) is another good indicator of soil trafficability.
Unified Soil Classification--The unified soil classification is a system of categorization of soil materials, particularly relevant for excavations and embankments of sewage lagoons as listed in Table 3. The classification is outlined for laymen in a publication by Olson (1972a), available from the Department of Agronomy (Soils), Cornell University, Ithaca, New York 14850. Briefly, the unified soil groups listed in Table 3 are:
- GW--Well-graded gravel, gravel and sand mixtures, little or no fines
- GP--Poorly graded gravel, gravel and sand mixtures, little or no fines
- GM--Silty gravel, gravel and sand and silt mixtures
- GC--Clayey gravel, gravel and sand and clay mixtures
- SW--Well-graded sands, gravelly sands, little or no fines
- SP--Poorly graded sands, gravelly sands, little or no fines
- SM--Silty sands, sand and silt mixtures
- SC--Clayey sands, sand and clay mixtures
- ML--Inorganic silts and very fine sands, rock flour, silty or clayey fine sands, or clayey silts with slight plasticity
- CL--Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, lean clays
- OL--Organic silts and organic silty clays of low plasticity
- MH--Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts
- CH--Inorganic clays of high plasticity, fat clays
- OH--Organic clays of medium to high plasticity, organic silts
- Pt--Peat and other highly organic soils
Water Table--Water table is the upper surface of ground water or that level below which the soil is saturated with water. Apparent water table is the level to which the water level rises when holes are dug in soils. Obviously, waste disposal is difficult when apparent water tables are high in soils. Table 1 lists the seasonal depths to apparent water table in Kansas soils.
1 inch = 2.54 centimeters (cm)
1 foot = 30.48 cm = 0.3048 (m)
1 mile = 1.609 kilometers (km)
1 centimeter = 0.39 inches
1 meter = 3.281 ft = 39.37 in
1 kilometer = 0.621 miles
1 square foot = 0.093 m2
1 square mile = 259 hectares (ha)
1 acre = 0.405 ha
1 hectare = 0.01 km2 = 2.471 acres
1 square kilometer = 0.386 mile2
1 cubic foot = 0.028 m3
1 cubic meter = 35.3 ft3
Kansas Geological Survey, Geology
Placed on web Aug. 7, 2009; originally published March 1974.
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