soil map units where Pp Pulaka pit soils is dominant
Soil properties
| Property | Value |
|---|---|
| Geographic distribution | Tuvalu |
| Landscape position | Pulaka pits have been artificially constructed and comprise a flat-floored depression excavated to the level of the water table (pit) surrounded by an elevated rim (spoil bank). The immediate substrate (parent material) of both the pulaka pit and the spoil bank are not stratigraphically in place - the pit is dug below the natural soil profile level into unmodified parent material, and the former natural surface and its soil have been buried by the spoil bank. |
| Soil parent material | Organic materials (leaves) and sand from the pit floor and other sources. |
| Slope | Flat (0-3°) |
| Surface outcrops | No surface outcrops |
| Brief soil profile description | Dark organic muck - an organic sandy loam· that does not usually have much profile differentiation. However, the break between the growing medium and substrate is usually quite sharp, the substrate frequently being compacted rather than loose |
| Soil profile texture | Organic sandy loam, compacted rather than loose, and continually reworked and with addition of fresh organic matter. Soil bulk density is low and organic content is high |
| Minimum effective rooting depth | > 75 cm |
| Soil pH (acidity) | pH ranges from 6.6-7.4 (neutral) |
| Salinity | Low, but some pits are abandoned due to increasing salinity |
| Soil fertility under natural conditions | Man-made soils with higher organic matter content from composting. Key chemical properties are dependant on composting practices. |
| Soil moisture regime | Ustic |
| Susceptibility to drought | Not generally susceptible to drought as pits dug out to the water table, intensively managed, and smaller pits are better shaded by surrounding trees |
| Soil drainage | Well drained |
| Susceptibility to waterlogging | Designed to be more likely than surrounding areas to have periods of waterlogging. |
| Susceptibility to flooding | Pits are more likely to flood during heavy rain than surrounding areas |
