soil map units where TuS Abatao series, moderately deep phase is dominant
Soil properties
| Property | Value |
|---|---|
| Geographic distribution | Tarawa, Abatao |
| Landscape position | Planar or very slightly concave areas away from coastal rampart or lagoon shore |
| Soil parent material | coralline sand and gravel |
| Slope | Flat (0 - 3°) |
| Surface outcrops | Many coral fragments (2-5 cm) on surface |
| Brief soil profile description | Soils showing similar morphological features to Abatao soils but having a lithic contact between 50 cm and 1 m are considered a moderately deep phase. One pedon examined (TRW 10) was very moist in the lower part of the profile (> 80 cm) indicating possible intrusion of groundwater into the profile. However, at the time of examination the groundwater table was at 125 cm. |
| Soil profile texture | Typically shows a moderately thick, black, very dark brown or dark brown gritty or sandy loam wlth only weakly developed structure overlying medium or fine sand that may be sllghtly stony in places and extends to depths greater than 1 m. |
| Minimum effective rooting depth | 50 - 100 cm |
| Soil pH (acidity) | Alkaline and highly calcareous pH values in water are usually above 8. |
| Salinity | - |
| Soil fertility under natural conditions | organic carbon and nitrogen levels are usually high in the A horizon, but very low in the subsoil; total and available phosphorus are generally low; CEC is usually moderate in the A horizon, low in the subsoil and free lime is found throughout the profile exchangeable magnesium is moderate but potassium is very low phosphate extractable sulphate sulphur levels are moderate in the topsoil but low in the subsoil. |
| Soil moisture regime | Ustic |
| Susceptibility to drought | Dries out in dry periods. |
| Soil drainage | Excessively drained |
| Susceptibility to waterlogging | Not susceptible to waterlogging |
| Susceptibility to flooding | Never floods |
