Wang et al. (2012), surface loess across China's Loess Plateau.¶
Source¶
Wang, Y. Q., Shao, M. A., & Liu, Z. P. (2012). Pedotransfer functions for predicting soil hydraulic properties of the Chinese Loess Plateau. Soil Science, 177, 424-432.
DOI: 10.1097/SS.0b013e318255a449
Scope¶
Territory: Surface soils across the entire Loess Plateau, China
Dataset: 382 surface (0-5 cm) sites; 252 derivation and 130 validation data sets.
Functions¶
calc_ptf_wang2012¶
Estimate saturated water content, field capacity, and saturated conductivity.
Status: implemented
Prediction target: Saturated soil-water content, water content at -33 kPa, and saturated hydraulic conductivity.
Models: \(h(\theta)\) — Point estimates at saturation and -33 kPa; \(k(h)\) — Saturated hydraulic conductivity
Inputs¶
| Name | Type | Unit | Domain | Description |
|---|---|---|---|---|
sand | number | % | 0.8 <= value <= 92.0 | Sand content, 0.05-1 mm. |
silt | number | % | 6.3 <= value <= 84.7 | Silt content, 0.002-0.05 mm. |
clay | number | % | 0.4 <= value <= 35.8 | Clay content, <0.002 mm. |
bulk_density | number | g/cm^3 | 1.04 <= value <= 1.82 | Bulk density. |
soil_organic_carbon | number | % | 0.033 <= value <= 3.369 | Soil organic carbon exposed by the public API as percent by mass. |
altitude | number | m | 99 <= value <= 2835 | Altitude above sea level. |
Outputs¶
| Name | Unit | Domain | Description |
|---|---|---|---|
theta_s | cm^3/cm^3 | value >= 0 | Saturated volumetric water content normalized from the regression's volume-percent scale. |
theta_fc | cm^3/cm^3 | value >= 0 | Volumetric water content at -33 kPa normalized from the regression's volume-percent scale. |
k_sat | m/s | value >= 0 | Saturated hydraulic conductivity converted from cm/day. |
Note
The regression uses source SOC in g/kg; the public API accepts percent.
Note
Base-10 logarithms reproduce the source's raw and transformed Ks ranges.
Note
Water-content equations are evaluated in percentage points and divided by 100 for public volumetric fractions.
Warning
This normalization intentionally changes the legacy water-content outputs by a factor of 100.