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Point water-retention regressions for tropical Sri Lankan soils.

Source

Gunarathna, M. H. J. P., Sakai, K., Nakandakari, T., Momii, K., Kumari, M. K. N., & Amarasekara, M. G. T. S. (2019). Pedotransfer functions to estimate hydraulic properties of tropical Sri Lankan soils. Soil & Tillage Research, 190, 109-119. https://doi.org/10.1016/j.still.2019.02.009

DOI: 10.1016/j.still.2019.02.009

Scope

Territory: Tropical Sri Lanka.

Dataset: 323 soil horizons retained after removing samples with missing water-content data from the SRI-CANSOL survey of 110 profiles. The survey covers almost all soil series and land uses except the northern part of Sri Lanka. Models were evaluated using tenfold cross-validation.

Functions

calc_ptf_gunarathna2019_vwc10_set1

Estimate volumetric water content at -10 kPa using Set 1.

Status: implemented

Prediction target: Volumetric water content at -10 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.

Outputs

Name Unit Domain Description
theta_10 mm/mm Volumetric water content at -10 kPa matric potential.

Note

Equation evidence: Table 3, VWC10, Set 1.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

Warning

Section 3.1 reports slight overprediction above 64% sand at this pressure.

calc_ptf_gunarathna2019_vwc10_set2

Estimate volumetric water content at -10 kPa using Set 2.

Status: implemented

Prediction target: Volumetric water content at -10 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
silt number % Table 1 observed range: 0.0 <= value <= 38.6 Silt percentage measured by the pipette method.

Outputs

Name Unit Domain Description
theta_10 mm/mm Volumetric water content at -10 kPa matric potential.

Note

Equation evidence: Table 3, VWC10, Set 2.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc10_set3

Estimate volumetric water content at -10 kPa using Set 3.

Status: implemented

Prediction target: Volumetric water content at -10 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
silt number % Table 1 observed range: 0.0 <= value <= 38.6 Silt percentage measured by the pipette method.
bulk_density number g/cm3 Table 1 observed range: 1.0 <= value <= 2.0 Bulk density measured using undisturbed cores.

Outputs

Name Unit Domain Description
theta_10 mm/mm Volumetric water content at -10 kPa matric potential.

Note

Equation evidence: Table 3, VWC10, Set 3.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc10_set4

Estimate volumetric water content at -10 kPa using Set 4.

Status: implemented

Prediction target: Volumetric water content at -10 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
silt number % Table 1 observed range: 0.0 <= value <= 38.6 Silt percentage measured by the pipette method.
organic_carbon number % Table 1 observed range: 0.0 <= value <= 4.5 Organic carbon percentage measured by the Walkley-Black method.

Outputs

Name Unit Domain Description
theta_10 mm/mm Volumetric water content at -10 kPa matric potential.

Note

Equation evidence: Table 3, VWC10, Set 4.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc33_set1

Estimate volumetric water content at -33 kPa using Set 1.

Status: implemented

Prediction target: Volumetric water content at -33 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.

Outputs

Name Unit Domain Description
theta_33 mm/mm Volumetric water content at -33 kPa matric potential.

Note

Equation evidence: Table 3, VWC33, Set 1.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

Warning

Section 3.1 reports slight overprediction above 66% sand at this pressure.

calc_ptf_gunarathna2019_vwc33_set2

Estimate volumetric water content at -33 kPa using Set 2.

Status: implemented

Prediction target: Volumetric water content at -33 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
silt number % Table 1 observed range: 0.0 <= value <= 38.6 Silt percentage measured by the pipette method.

Outputs

Name Unit Domain Description
theta_33 mm/mm Volumetric water content at -33 kPa matric potential.

Note

Equation evidence: Table 3, VWC33, Set 2.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc33_set3

Estimate volumetric water content at -33 kPa using Set 3.

Status: implemented

Prediction target: Volumetric water content at -33 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
silt number % Table 1 observed range: 0.0 <= value <= 38.6 Silt percentage measured by the pipette method.
bulk_density number g/cm3 Table 1 observed range: 1.0 <= value <= 2.0 Bulk density measured using undisturbed cores.

Outputs

Name Unit Domain Description
theta_33 mm/mm Volumetric water content at -33 kPa matric potential.

Note

Equation evidence: Table 3, VWC33, Set 3.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc33_set4

Estimate volumetric water content at -33 kPa using Set 4.

Status: implemented

Prediction target: Volumetric water content at -33 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
silt number % Table 1 observed range: 0.0 <= value <= 38.6 Silt percentage measured by the pipette method.
organic_carbon number % Table 1 observed range: 0.0 <= value <= 4.5 Organic carbon percentage measured by the Walkley-Black method.

Outputs

Name Unit Domain Description
theta_33 mm/mm Volumetric water content at -33 kPa matric potential.

Note

Equation evidence: Table 3, VWC33, Set 4.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc1500_set1

Estimate volumetric water content at -1500 kPa using Set 1.

Status: implemented

Prediction target: Volumetric water content at -1500 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.

Outputs

Name Unit Domain Description
theta_1500 mm/mm Volumetric water content at -1500 kPa matric potential.

Note

Equation evidence: Table 3, VWC1500, Set 1.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

Warning

Section 3.1 reports slight overprediction above 66% sand at this pressure.

calc_ptf_gunarathna2019_vwc1500_set3

Estimate volumetric water content at -1500 kPa using Set 3.

Status: implemented

Prediction target: Volumetric water content at -1500 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
bulk_density number g/cm3 Table 1 observed range: 1.0 <= value <= 2.0 Bulk density measured using undisturbed cores.

Outputs

Name Unit Domain Description
theta_1500 mm/mm Volumetric water content at -1500 kPa matric potential.

Note

Equation evidence: Table 3, VWC1500, Set 3.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.

calc_ptf_gunarathna2019_vwc1500_set4

Estimate volumetric water content at -1500 kPa using Set 4.

Status: implemented

Prediction target: Volumetric water content at -1500 kPa.

Inputs

Name Type Unit Domain Description
sand number % Table 1 observed range: 5.2 <= value <= 99.0 Sand percentage measured by sieve analysis.
organic_carbon number % Table 1 observed range: 0.0 <= value <= 4.5 Organic carbon percentage measured by the Walkley-Black method.

Outputs

Name Unit Domain Description
theta_1500 mm/mm Volumetric water content at -1500 kPa matric potential.

Note

Equation evidence: Table 3, VWC1500, Set 4.

Note

Input ranges describe the study observations, not enforced validity limits.

Warning

Predictions are empirical and are not clipped to physical bounds.