Soil type characteristics:
Nitisols occur mainly in the tropics and subtropics, as well as in areas with a Mediterranean type of climate. They are associated with basic rocks (e.g. basalts) or hard limestone or dolomite deposits.
Characteristics
Soils having a nitic horizon (a horizon with pronounced nut-shaped soil structure and significant amount of active iron) within 100 cm from the soil surface, and gradual to diffuse horizon boundaries between the surface and the underlying horizons. They do not have a ferric, plinthic or vertic horizon within 100 cm from the soil surface.
Distribution of Nitisols (rough estimation supplied by soilgrids)
Description:
Reference soil KE044: Nitisols
Brief soil description: Very deep, well drained soil derived from basic volcanic breccia; with a thick, dusky red clay topsoil over a dark brown, clay subsoil with clay cutans. The soil is used for arable farming with crops as coffee, maize, bananas and cassava. Charcoal and potterie are found troughout the 0 - 80cm soil hrizon Termite activity is very high. Slides: 10,052 - 10,059.
General information:
| Location | Central Province,Embu district, near Kathungu coffee factory |
| Authors | Kuyper J & W Simons |
| Köppen | Am |
| Date | 1985-09-01 |
| Lat/Lon | -0.4111, 37.6278 |
Code:
KE044
Parent material
| Kind 1 (parent material) ; Parker (eds), 1984 | basic volcanic breccia |
| Soil Depth | 150cm |
| Texture of parent material | clayey |
| Remarks on Parent Materials | phonolite/lahar |
| Weathering Resistance | moderate |
| General characterization of the status of weathering of solid rock | highly |
| Mode of accumulation or deposition of parent material | residual material |
Physiography
| Altitude | 1410m |
| Slope | 3% |
| Physiographic Unit | dissected mountain footridge |
| Form of the slope surrounding the site | convex |
| Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne. | plateau |
| Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | undulating |
| Physiographic position of the site | upper slope |
Hydrology and drainage
| Estimated permeability (class) of least permeable part of the profile | moderate |
| Dry From - To | 0-150cm |
| Kind of ground water table (USDA, 1979) | no groundwater table observed |
| Estimated run off (class) | medium |
| Drainage class ; FAO (2006) - Guidelines for soil description | well |
| Flooding frequency (FAO, 1986) | never |
Erosion and degradation
| Slope stability | stable |
| Occurrence of soil aggradation (McDonald et al., 1984) | absent |
Land use
| Remarks on Land Use / Vegetation | LAND USE: Crops also some maize, bananas, cassava |
| Land use or vegetation in the immediate vicinity of the site | medium level arable farming |
| Major crops | coffee |
| Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | crop rotation scheme not relevant |
| Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | no irrigation |
| Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006) | terracing |
Surface characteristics
| Evidence of salt; Soil Survey Manual USDA, 1951 | non-saline |
| Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979) | no surface slaking/crusting observed |
| Microrelief pattern | none |
| 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 |
| Surface cracking | no cracks observed |
Classification
WRB 2006
| Ferralic Mollic Lixic Nitisols (Humic Rhodic ) |
| 0-60 | mollic horizon |
| 35-150 | argic horizon |
| - | ferralic horizon |
| 35-150 | nitic horizon |
WRB 1998
| Mollic Humi Rhodic Ferralic Nitisols |
FAO-UNESCO-ISRIC 1974
| Luvic Phaeozems |
| 0-80 cm | mollic A horizon |
| 35-150 cm | argillic B horizon |
Other classification
| USDA-NRCS (1999) | Pachic Argiudoll |
| USDA-SCS (1975) | Pachic Argiudoll udic very fine isothermic |
Other
| Description of a site | Brief soil description: Very deep, well drained soil derived from basic volcanic breccia; with a thick, dusky red clay topsoil over a dark brown, clay subsoil with clay cutans. The soil is used for arable farming with crops as coffee, maize, bananas and cassava. Charcoal and potterie are found troughout the 0 - 80cm soil hrizon Termite activity is very high. Slides: 10,052 - 10,059. |
Climate data
| Description | record | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Precipitation (mm) | 18 | 25 | 40 | 146 | 396 | 218 | 25 | 41 | 42 | 21 | 284 | 321 | 73 | 1632 |
| Maximum temperature (°C) | 11 | 26.4 | 29.3 | 27.9 | 25.8 | 24 | 22.8 | 21.4 | 21.7 | 24.4 | 25.9 | 24.2 | 25.7 | 25 |
| Minimum temperature (°C) | 11 | 13.6 | 13.6 | 14.9 | 15.8 | 15.7 | 14.4 | 13.1 | 13 | 13.3 | 14.2 | 14.6 | 13.6 | 14.2 |
| Precipitation (mm) | 33 | 22 | 25 | 91 | 301 | 224 | 28 | 45 | 43 | 42 | 147 | 203 | 59 | 1230 |
| Station: | Ruyenjes |
| Country: | Kenya |
| WMO Code: | 99.999 |
| Altitude: | 0 |
| Latitude/Longitude | S0°25 E37°36 |
Profile description
| Ah 0-35 cm | dark reddish brown (5YR 3/2, dry) dusky red (2.5YR 3/2, moist)clay,weak coarse and very coarse subangular blocky parting to moderate fine granular,soft very friable sticky slightly plastic,patchy thin clay cutans,many micro and very fine and few fine and medium pores,many very fine and common medium roots,non calcareous,gradual irregular boundary to, |
| AB 35-80 cm | dark brown (7.5YR 3/2, dry) dark brown (7.5YR 3/2, moist)clay,moderate very coarse subangular blocky,slightly hard friable sticky slightly plastic,broken thin clay cutans,many micro and very fine pores and few fine and medium pores,non calcareous,gradual wavy boundary to, |
| Bt 80-150 cm | dark reddish brown (5YR 3/4, dry) dusky red (2.5YR 3/2, moist)clay,strong very coarse subangular blocky,hard firm sticky slightly plastic,continuous moderately thick clay cutans,many micro and very fine pores and few fine and medium pores,very few small spherical hard ferruginous concretions,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 |
| 0-35 | 2.37 | 15.5 | 0.8 | 8 | 0.20 | - | - | 2.1 | 3.1 | 0.30 | 0.0 | 6.6 | 5.6 | 20.7 |
| 35-60 | 1.33 | 13.3 | 1.4 | 8 | 0.16 | - | - | 1.4 | 3.0 | 0.17 | 0.0 | 6.9 | 5.7 | 17.7 |
| 60-90 | 0.63 | 7.1 | 1.3 | 6 | 0.21 | - | - | 1.5 | 2.2 | 0.11 | 0.0 | 7.0 | 5.8 | 10.8 |
| 90-150 | 0.57 | 6.9 | 1.0 | 6 | 0.19 | - | - | 1.9 | 2.8 | 0.10 | 0.1 | 7.0 | 5.9 | 11.7 |
| 150- | 0.35 | 5.4 | 1.1 | 5 | 0.14 | - | - | 1.1 | 3.2 | 0.07 | 0.0 | 6.9 | 5.9 | 9.7 |
| 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 % |
| 0-35 | - | 93 | 65 | 8.3 | 22.3 | - | 0 |
| 35-60 | - | 122 | 29 | 4.7 | 14.5 | - | 0 |
| 60-90 | - | 98 | 19 | 2.2 | 11 | - | 0 |
| 90-150 | - | 119 | 16 | 2.0 | 9.8 | - | 1 |
| 150- | - | 114 | 10 | 1.2 | 8.5 | - | 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 |
| 0-35 | 0.5 | 0.5 | - | - | 6.2 | 0.5 | - | - | - | - | 0.1 |
| 35-60 | 0.6 | 0.3 | - | - | 8.7 | 0.4 | - | - | - | - | 0.1 |
| 60-90 | 0.5 | 0.2 | - | - | 6.0 | 0.5 | - | - | - | - | 0.1 |
| 90-150 | 0.5 | 0.3 | - | - | 6.1 | 0.5 | - | - | - | - | 0.1 |
| 150- | 0.6 | 0.3 | - | - | 6.4 | 0.5 | - | - | - | - | 0.1 |
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 |
| 0-35 | 34.4 | 1.3 | 18.6 | 1.3 | 41.3 | - | 1.1 | 5.7 | 59.9 | 1.0 | 1.0 |
| 35-60 | 49.2 | 0.5 | 10.7 | 1.0 | 36.7 | - | 0.6 | 3.3 | 47.4 | 0.4 | 0.8 |
| 60-90 | 57.8 | 0.1 | 7.1 | 0.9 | 33.2 | - | 0.3 | 2 | 40.3 | 0.1 | 0.6 |
| 90-150 | 59.8 | 0.2 | 4.9 | 0.9 | 33.3 | - | 0.3 | 2 | 38.2 | 0.0 | 0.6 |
| 150- | 82.0 | 0.1 | 1.6 | 0.8 | 14.6 | - | 0.3 | 1.8 | 16.2 | 0.0 | 0.6 |
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 | 0.915 | - | - | - | - |
| 0-35 | - | 34.4 | - | - | 24.1 |
| 35-60 | - | 49.2 | - | - | 31.6 |
| 48-53 | 1.011 | - | - | - | - |
| 60-90 | - | 57.8 | - | - | 28.5 |
| 98-103 | 0.953 | - | - | - | - |
| 90-150 | - | 59.8 | - | - | - |
| 150- | - | 82.0 | - | - | - |
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 | 0.915 | 64.0 | 60.4 | 48.1 | 38.8 | 35.7 | 33.3 | 30.1 | 28.3 |
| 48-53 | 1.011 | 56.5 | 53.6 | 47.9 | 43.4 | 41.2 | 39.3 | 37.7 | 35.0 |
| 98-103 | 0.953 | 56.3 | 53.8 | 49.2 | 42.8 | 39.7 | 37.4 | 36.2 | 32.7 |
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 |
| 0-35 | - | - | weak | weak | - | - | medium | - | weak | - | - | - |
| 35-60 | - | - | weak | weak | - | - | medium | - | weak | - | - | - |
| 60-90 | - | - | weak | weak | - | - | medium to strong | - | weak | - | - | - |
| 90-150 | - | - | weak | weak | - | - | medium to strong | - | weak | - | - | - |
| 150- | - | - | weak | weak | - | - | medium to strong | - | very weak to weak | - | - | - |
