soil map units where Va3 Vaini soils, low-lying phase is dominant
Soil properties
| Property | Value |
|---|---|
| Geographic distribution | Tongatapu |
| Landscape position | Uplifted ash-mantled coral surface. |
| Soil parent material | - |
| Slope | Flat to gently undulating (0-5°) |
| Surface outcrops | - |
| Brief soil profile description | 0-32 cm Dark reddish brown friable clay; few red lapilli; 32-88 cm Dark reddish brown firm clay; weathered lapilli; 88-170+cm brown heavy, firm clay; clay coatings; on Coral limestone |
| Soil profile texture | - |
| Minimum effective rooting depth | 150 cm+ |
| Soil pH (acidity) | Near neutral to slightly alkaline |
| Salinity | - |
| Soil fertility under natural conditions | High to very high Base saturation (%), calcium (Ca) and magnesium (Mg). phosphorus (P) high in A horizon decreasing with depth; phosphorus (P) retention high; reserve potassium (K) low to very low. |
| Soil moisture regime | - |
| Susceptibility to drought | - |
| Soil drainage | Poorly drained |
| Susceptibility to waterlogging | - |
| Susceptibility to flooding | - |
