Soil type characteristics:
Ferralsols occur in tropical and subtropical regions of the world, mainly on old and stable land surfaces.
Characteristics
Soils having a ferralic horizon (strongly weathered horizon with low-activity clays and very low amounts of weatherable minerals) between 25 and 200 cm from the soil surface. They lack a nitic horizon (a horizon with strongly developed, nut-shaped structure) and do not have a layer which fulfils the requirements of an argic horizon and which has, in the upper 30 cm, 10 percent or more water-dispersible clay.
Distribution of Ferralsols (rough estimation supplied by soilgrids)
Description:
Reference soil KE006: Ferralsols
thin surface sealing, 3 mm thick
General information:
| Köppen | C |
| Location | Embu District, 4km N of Siakogo, along road |
| Authors | Van de Weg RF & JP Mbuvi |
| Date | 1972-01-01 |
| Lat/Lon | -0.5522, 37.4517 |
Code:
KE006
Parent material
| Texture of parent material | clayey |
| Remarks on Parent Materials | Precambrian basement complex |
| Weathering Resistance | moderate |
| Mode of accumulation or deposition of parent material | residual material |
| General characterization of the status of weathering of solid rock | highly |
| Kind 1 (parent material) ; Parker (eds), 1984 | gneiss |
Physiography
| Physiographic Unit | basement system |
| Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne. | pediplain |
| Slope | 1% |
| Altitude | 1260m |
| Physiographic position of the site | flat |
| Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | flat or almost flat |
Hydrology and drainage
| Kind of ground water table (USDA, 1979) | no groundwater table observed |
| Estimated run off (class) | slow |
| Flooding frequency (FAO, 1986) | never |
| Drainage class ; FAO (2006) - Guidelines for soil description | well |
| Estimated permeability (class) of least permeable part of the profile | slow |
Land use
| Remarks on Land Use / Vegetation | VEGETATION: Bushed wooded grassland |
| Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | deciduous shrub |
| Land use or vegetation in the immediate vicinity of the site | semi-natural grassland, grazed |
| Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | crop rotation scheme not relevant |
Surface characteristics
| Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979) | surface slaked; sorted sand/silt, some clay films |
| Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986) | termite/ant mounds |
| Evidence of salt; Soil Survey Manual USDA, 1951 | non-saline |
| Surface stoniness class (FAO (2006) - Guidelines for soil description) | none |
| Rock outcrop class (FAO (2006) - Guidelines for soil description) | none |
| Evidence of alkali ; Soil Survey Manual USDA, 1951 | non-alkaline |
Classification
WRB 2006
| Mollic Ferralsols (Humic Eutric Clayic ) |
| 60-190 | ferralic horizon |
| 0-32 | mollic horizon |
WRB 1998
| Mollihumic Rhodi Ferralsols |
FAO-UNESCO-ISRIC 1974
| Rhodic Ferralsols |
| - | high organic matter content in B horizon horizon |
| 0-32 cm | mollic A horizon |
| 60-190 cm | oxic B horizon |
Other classification
| USDA-SCS (1975) | Eutrustox ustic clayey kaolinitic thermic |
Other
| Description of a site | thin surface sealing, 3 mm thick |
Profile description
| Ah 0-32 cm | dusky red (2.5YR 3/2, moist)clay,weak to moderate very fine and fine subangular blocky,friable slightly sticky slightly plastic,common very fine and fine pores,many fine and common medium roots,non calcareous,clear smooth boundary to, |
| Bo1 60-122 cm | dark red (2.5YR 3/6, moist)dark reddish brown (2.5YR 3/4, moist),clay,clay,moderate medium subangular blocky,moderate medium subangular blocky,friable sticky plastic,very friable slightly sticky slightly plastic,many very fine and fine pores,many very fine to medium pores,few fine roots,many fine and few medium roots,non calcareous,non calcareous,gradual smooth boundary to,gradual smooth boundary to, |
| Bo2 122-140 cm | dark red (2.5YR 3/6, moist)clay,weak fine subangular blocky,very friable slightly sticky slightly plastic,common very fine and fine pores,few fine roots,non calcareous, |
Chemical characteristics
| Depth (cm) | C % weight/weight | Ca cmol(c)/kg | CaCO3 % weight/weight | C / N unitless | EC 1: 2.5 mS/cm | Exch. Acid cmol(c)/kg | Exch. Al cmol(c)/kg | K cmol(c)/kg | Mg cmol(c)/kg | N % | Na cmol(c)/kg | pH H2O unitless | pHKCl unitless | Sum Cations cmol(c)/kg |
| 0-16 | 2.59 | 6.2 | - | 20 | 0.10 | 0.1 | 0.0 | 0.7 | 2.2 | 0.13 | 0.0 | 5.6 | 4.8 | 9.1 |
| 16-32 | 1.67 | 10.1 | - | 17 | 0.08 | 0.1 | 0.2 | 0.5 | 1.4 | 0.10 | 0.0 | 5.3 | 4.5 | 12 |
| 32-60 | 1.04 | 3.5 | - | 15 | 0.06 | 0.1 | 0.2 | 0.4 | 1.1 | 0.07 | 0.0 | 5.3 | 4.8 | 5 |
| 60-90 | 0.74 | 2.9 | - | 19 | 0.06 | 0.0 | 0.2 | 0.3 | 0.7 | 0.04 | 0.0 | 5.2 | 5.0 | 3.9 |
| 90-120 | 0.64 | 2.7 | - | 13 | 0.05 | 0.1 | 0.2 | 0.2 | 0.7 | 0.05 | 0.0 | 4.8 | 4.6 | 3.6 |
| 120-160 | 0.54 | 2.5 | - | 18 | 0.05 | 0.0 | 0.2 | 0.3 | 1.0 | 0.03 | 0.0 | 5.1 | 5.1 | 3.8 |
| 160-190 | 0.52 | 2.7 | - | 17 | 0.05 | 0.0 | 0.2 | 0.2 | 1.2 | 0.03 | 0.0 | 5.2 | 5.2 | 4.1 |
| Depth (cm) | Al sat. % | Base sat. % | CEC clay cmol(c)/kg | CEC org cmol(c)/kg | CEC soil cmol(c)/kg | ECEC cmol(c)/kg | ESP % |
| 0-16 | 0 | 57 | 29 | 9.1 | 15.9 | - | 0 |
| 16-32 | 2 | 94 | 21 | 5.8 | 12.8 | - | 0 |
| 32-60 | 2 | 59 | 14 | 3.6 | 8.5 | - | 0 |
| 60-90 | 3 | 53 | 12 | 2.6 | 7.4 | - | 0 |
| 90-120 | 3 | 49 | 11 | 2.2 | 7.4 | - | 0 |
| 120-160 | 3 | 51 | 11 | 1.9 | 7.4 | - | 0 |
| 160-190 | 3 | 53 | 11 | 1.8 | 7.7 | - | 0 |
| Depth (cm) | Al d % weight/weight | Al o % weight/weight | Al p % weight/weight | C p % weight/weight | Fe d % weight/weight | Fe o % weight/weight | Fe p % weight/weight | ODOE unitless | pH NaF unitless | P Retention % | Si o % weight/weight |
| 0-16 | 0.32 | 0.26 | 0.10 | - | 4.60 | 0.25 | 0.09 | - | - | - | 0.10 |
| 16-32 | 0.35 | 0.30 | 0.19 | - | 4.89 | 0.30 | 0.10 | - | - | - | 0.10 |
| 32-60 | 0.36 | 0.29 | 0.13 | - | 4.90 | 0.29 | 0.05 | - | - | - | 0.10 |
| 60-90 | 0.41 | 0.31 | 0.09 | - | 5.15 | 0.28 | 0.02 | - | - | - | 0.10 |
| 90-120 | 0.45 | 0.30 | 0.09 | - | 5.44 | 0.31 | 0.02 | - | - | - | 0.10 |
| 120-160 | 0.44 | 0.30 | 0.08 | - | 5.63 | 0.32 | 0.01 | - | - | - | 0.10 |
| 160-190 | 0.44 | 0.28 | 0.07 | - | 5.47 | 0.33 | 0.01 | - | - | - | 0.10 |
Physical characteristics
Particle size distribution
| Depth (cm) | Clay % weight/weight | coarse sand % weight/weight | coarse silt % weight/weight | fine sand % weight/weight | fine silt % weight/weight | Gravel % volume/volume | medium sand % weight/weight | Total sand % weight/weight | Total silt % weight/weight | very coarse sand % weight/weight | very fine sand % weight/weight |
| 0-16 | 54.3 | 1.6 | 4.1 | 16.7 | 7.7 | - | 8.6 | 33.9 | 11.8 | 0.3 | 6.7 |
| 16-32 | 60.7 | 1.0 | 4.8 | 15.7 | 4.4 | - | 7.2 | 30.2 | 9.2 | 0.2 | 6.1 |
| 32-60 | 62.2 | 0.9 | 4.7 | 15.9 | 3.8 | - | 6.2 | 29.3 | 8.5 | 0.2 | 6.1 |
| 60-90 | 64.2 | 0.9 | 4.4 | 14.3 | 4.5 | - | 5.1 | 26.8 | 8.9 | 0.3 | 6.2 |
| 90-120 | 66.8 | 0.9 | 4.4 | 12.7 | 4.5 | - | 4.3 | 24.3 | 8.9 | 0.1 | 6.3 |
| 120-160 | 67.5 | 0.9 | 5.5 | 11.1 | 4.9 | - | 3.5 | 22.2 | 10.4 | 0.4 | 6.3 |
| 160-190 | 68.4 | 0.8 | 6.3 | 9.8 | 5.2 | - | 3.0 | 20.1 | 11.5 | 0.4 | 6.1 |
Other physical data
| Depth (cm) | Bulk density kg/dm³ | Clay % weight/weight | COLE cm/cm | Spec. Surf. Area m²/g | Water disp. clay % |
| 8-13 | 1.00 | - | - | 91 | - |
| 0-16 | - | 54.3 | - | 91 | 17.1 |
| 16-32 | - | 60.7 | - | 91 | 20.0 |
| 85-90 | 1.04 | - | - | 89 | - |
| 170-175 | 1.04 | - | - | 94 | - |
| 32-60 | - | 62.2 | - | 89 | 16.3 |
| 60-90 | - | 64.2 | - | 89 | 4.5 |
| 90-120 | - | 66.8 | - | 93 | 1.5 |
| 120-160 | - | 67.5 | - | 92 | 4.0 |
| 160-190 | - | 68.4 | - | 94 | 2.0 |
Water retention characteristics
| Depth (cm) | Bulk density kg/dm³ | pF 0 % volume/volume | pF 1.0 % volume/volume | pF 1.5 % volume/volume | pF 2.0 % volume/volume | pF 2.3 % volume/volume | pF 2.7 % volume/volume | pF 3.4 % volume/volume | pF 4.2 % volume/volume |
| 8-13 | 1.00 | 55.5 | 55.2 | 43.6 | 29.6 | 26.5 | 24.4 | 20.6 | 16.3 |
| 85-90 | 1.04 | 55.4 | 53.4 | 46.6 | 35.7 | 26.9 | 20.7 | 19.9 | - |
| 170-175 | 1.04 | 55.9 | 55.9 | 50.5 | 39.1 | 33.0 | 28.7 | 24.0 | 22.9 |
Elemental composition of the clay
| Depth (cm) | Al2O3 % weight/weight | CaO % weight/weight | Fe2O3 % weight/weight | K2O % weight/weight | MgO % weight/weight | Na2O % weight/weight | SiO2 % weight/weight | TiO2 % weight/weight |
| 60-90 | 34.0 | 0.03 | 13.3 | 0.31 | 0.13 | - | 37.2 | 1.24 |
| 120-160 | 34.7 | 0.03 | 13.9 | 0.29 | 0.14 | - | 38.4 | 1.31 |
| Depth (cm) | Al2O3/Fe2O3 mol/mol | Ign.Loss clay % weight/weight | MnO2 % weight/weight | P2O5 % weight/weight | SiO2/Al2O3 mol/mol | SiO2/Fe2O3 mol/mol | SiO2 / R mol/mol | Total Clay % weight/weight |
| 60-90 | 4 | 13.9 | 0.09 | 0.11 | 1.9 | 7.4 | 1.5 | 100.31 |
| 120-160 | 3.9 | 13.7 | 0.07 | 0.09 | 1.9 | 7.3 | 1.5 | 102.63 |
Elemental composition of the soil
| Depth (cm) | Al2O3 % weight/weight | CaO % weight/weight | Fe2O3 % weight/weight | K2O % weight/weight | MgO % weight/weight | Na2O % weight/weight | SiO2 % weight/weight | TiO2 % weight/weight |
| 0-16 | 18.6 | 0.26 | 8.2 | 0.55 | 0.16 | - | 59.4 | 1.02 |
| 16-32 | 20.6 | 0.17 | 8.6 | 0.51 | 0.14 | - | 57.9 | 1.04 |
| 32-60 | 21.5 | 0.13 | 9.0 | 0.49 | 0.11 | - | 57.9 | 1.07 |
| 60-90 | 22.8 | 0.12 | 9.6 | 0.48 | 0.14 | - | 55.9 | 1.13 |
| 90-120 | 23.4 | 0.09 | 9.9 | 0.48 | 0.12 | - | 55.3 | 1.16 |
| 120-160 | 24.1 | 0.10 | 10.3 | 0.47 | 0.13 | - | 53.3 | 1.20 |
| 160-190 | 25.1 | 0.09 | 10.7 | 0.46 | 0.13 | - | 52.8 | 1.22 |
| Depth (cm) | Al2O3/Fe2O3 mol/mol | LOI % weight/weight | MnO2 % weight/weight | P2O5 % weight/weight | SiO2 / Al2O3 mol/mol | SiO2/Fe2O3 mol/mol | SiO2 / R mol/mol |
| 0-16 | 3.6 | 11.3 | 0.14 | 0.10 | 5.4 | 19.3 | 4.2 |
| 16-32 | 3.8 | 10.5 | 0.12 | 0.08 | 4.8 | 17.9 | 3.8 |
| 32-60 | 3.7 | 9.8 | 0.09 | 0.08 | 4.6 | 17.1 | 3.6 |
| 60-90 | 3.7 | 9.7 | 0.09 | 0.05 | 4.2 | 15.5 | 3.3 |
| 90-120 | 3.7 | 10.0 | 0.08 | 0.05 | 4 | 14.9 | 3.2 |
| 120-160 | 3.7 | 10.1 | 0.07 | 0.05 | 3.8 | 13.8 | 2.9 |
| 160-190 | 3.7 | 10.5 | 0.08 | 0.05 | 3.6 | 13.1 | 2.8 |
Clay mineralogy
| Depth (cm) | Chlorite unitless | Feldspar unitless | Gibbsite unitless | Goethite unitless | Halloysite unitless | Hematite unitless | Kaolinite unitless | Mica / illite unitless | Mixed-layer unitless | Quartz unitless | Smec unitless | Vermiculite unitless |
| 0-16 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
| 16-32 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
| 32-60 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
| 60-90 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
| 90-120 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
| 120-160 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
| 160-190 | - | - | weak to medium | weak | - | - | strong | - | weak | - | - | - |
Mineral sand
| Depth (cm) | Heavy Frac. sand % weight/weight | K-Feldspar % weight/weight | Light Fra. sand % weight/weight | Opaque % weight/weight | Plagioclase % weight/weight | Quartz % weight/weight |
| 120-160 | 0.5 | 6 | 99.5 | 91 | 1 | 93 |
Minerals
| Depth (cm) | Anatase % weight/weight | Andalusite % weight/weight | Apatite % weight/weight | Augite % weight/weight | Biotite % weight/weight | Hornblende (basaltic) % weight/weight |
| 120-160 | - | - | - | - | - | 4 |
| Depth (cm) | Brookite % weight/weight | Chloritic % weight/weight | Disthene % weight/weight | Epidote % weight/weight | Garnet % weight/weight | Glaucophane % weight/weight |
| 120-160 | - | - | 1 | 9 | - | - |
| Depth (cm) | Grenate % weight/weight | Grossular % weight/weight | Muscovite % weight/weight | Rutile % weight/weight | Sillimanite % weight/weight | Spinel % weight/weight |
| 120-160 | 2 | - | - | 5 | 1 | - |
