soil map units where Tu Abatao series 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 | Profile features can be variable particularly with regard to depth and texture of the topsoil. Depths can vary from 15-32cm with the upper part of the A horizon usually being darker than the lower part in the content of organic matter cause texture variations. In the subsoil the texture may be medium or fine sand with varying amounts of gravels and stones. |
| 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 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 |
