Rawls et al. (1982), water-retention regressions for soils across the USA.¶
Source¶
Rawls, W. J., Brakensiek, D. L., & Saxton, K. E. (1982). Estimation of soil water properties. Transactions of the ASAE, 25, 1316-1320.
Scope¶
Territory: Agricultural soils from 32 states of the USA
Dataset: 1,323 soils with about 5,350 horizons; regression equations used 2,541 horizons.
Functions¶
calc_theta_1500_rawls1982¶
Estimate volumetric water content at -1500 kPa.
Status: implemented
Prediction target: Volumetric soil water content at -1500 kPa.
Models: \(h(\theta)\) — Point estimate at -1500 kPa
Inputs¶
| Name | Type | Unit | Domain | Description |
|---|---|---|---|---|
clay | number | % | 0.1 <= value <= 94 | Clay content. |
organic_matter | number | % | 0.1 <= value <= 12.5 | Organic matter content. |
Outputs¶
| Name | Unit | Domain | Description |
|---|---|---|---|
theta_1500 | cm^3/cm^3 | value >= 0 | Volumetric soil water content at -1500 kPa. |
calc_theta_33_rawls1982¶
Estimate volumetric water content at -33 kPa using measured or estimated theta_1500.
Status: implemented
Prediction target: Volumetric soil water content at -33 kPa.
Models: \(h(\theta)\) — Point estimate at -33 kPa
Inputs¶
| Name | Type | Unit | Domain | Description |
|---|---|---|---|---|
sand | number | % | 0.1 <= value <= 99 | Sand content. |
organic_matter | number | % | 0.1 <= value <= 12.5 | Organic matter content. |
theta_1500 | number | cm^3/cm^3 | value >= 0 | Measured or estimated volumetric water content at -1500 kPa. |
Outputs¶
| Name | Unit | Domain | Description |
|---|---|---|---|
theta_33 | cm^3/cm^3 | value >= 0 | Volumetric soil water content at -33 kPa. |
calc_full_wrc_rawls1982¶
Estimate a twelve-point water-retention curve using theta_33 and theta_1500.
Status: implemented
Prediction target: Volumetric water contents from -4 to -1500 kPa.
Models: \(h(\theta)\) — Twelve point water-retention curve
Inputs¶
| Name | Type | Unit | Domain | Description |
|---|---|---|---|---|
sand | number | % | 0.1 <= value <= 99 | Sand content. |
organic_matter | number | % | 0.1 <= value <= 12.5 | Organic matter content. |
bulk_density | number | g/cm^3 | 0.1 <= value <= 2.09 | Bulk density. |
theta_33 | number | cm^3/cm^3 | value >= 0 | Measured or estimated volumetric water content at -33 kPa. |
theta_1500 | number | cm^3/cm^3 | value >= 0 | Measured or estimated volumetric water content at -1500 kPa. |
Outputs¶
| Name | Unit | Domain | Description |
|---|---|---|---|
theta_4 | cm^3/cm^3 | — | Volumetric water content at -4 kPa. |
theta_7 | cm^3/cm^3 | — | Volumetric water content at -7 kPa. |
theta_10 | cm^3/cm^3 | — | Volumetric water content at -10 kPa. |
theta_20 | cm^3/cm^3 | — | Volumetric water content at -20 kPa. |
theta_33 | cm^3/cm^3 | — | Input volumetric water content at -33 kPa. |
theta_60 | cm^3/cm^3 | — | Volumetric water content at -60 kPa. |
theta_100 | cm^3/cm^3 | — | Volumetric water content at -100 kPa. |
theta_200 | cm^3/cm^3 | — | Volumetric water content at -200 kPa. |
theta_400 | cm^3/cm^3 | — | Volumetric water content at -400 kPa. |
theta_700 | cm^3/cm^3 | — | Volumetric water content at -700 kPa. |
theta_1000 | cm^3/cm^3 | — | Volumetric water content at -1000 kPa. |
theta_1500 | cm^3/cm^3 | — | Input volumetric water content at -1500 kPa. |
Note
The source offers three regression levels; this function uses measured theta_33 and theta_1500 for the intermediate points.
Warning
The source value 0.8888 is retained literally for the theta_7 intercept.