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ptfkit.mayr1999

ptfkit.mayr1999

Mayr and Jarvis (1999) modified Brooks-Corey water-retention parameter PTFs.

Reference

Mayr, T., & Jarvis, N. J. (1999). Pedotransfer functions to estimate soil water retention parameters for a modified Brooks-Corey type model. Geoderma, 91(1-2), 1-9. DOI: 10.1016/S0016-7061(98)00129-3

Territory

England and Wales

Dataset

Soil Survey and Land Research Centre soil physical properties database; regressions used 286 soil horizons retained from a 306-horizon subset after excluding fits with RMSE greater than 0.05 m^3/m^3, and validation used 1678 independent soil horizons.

CLASS DESCRIPTION
Mayr1999PTFResult

Results returned by the matching PTF.
FUNCTION DESCRIPTION
calc_ptf_mayr1999

Calculate the pedotransfer function.

Mayr1999PTFResult

Bases: NamedTuple, Generic[T]

Results returned by the matching PTF.

ATTRIBUTE DESCRIPTION
a_hc

Hutson-Cass fitting parameter with pressure-head dimensions. (cm H2O)

TYPE: T

b_hc

Hutson-Cass fitting parameter controlling retention-curve shape. (dimensionless)

TYPE: T

theta_s

Volumetric soil water content at saturation. (m^3/m^3)

TYPE: T

Source code in ptfkit/mayr1999.py 
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class Mayr1999PTFResult(NamedTuple, Generic[T]):
    """Results returned by the matching PTF.

    Attributes:
        a_hc: Hutson-Cass fitting parameter with pressure-head dimensions. (cm H2O)
        b_hc: Hutson-Cass fitting parameter controlling retention-curve shape. (dimensionless)
        theta_s: Volumetric soil water content at saturation. (m^3/m^3)

    """

    a_hc: T
    b_hc: T
    theta_s: T

calc_ptf_mayr1999 

calc_ptf_mayr1999(*, sand: float, silt: float, clay: float, bulk_density: float, organic_carbon: float) -> Mayr1999PTFResult[floating]

calc_ptf_mayr1999(*, sand: ArrayLike, silt: ArrayLike, clay: ArrayLike, bulk_density: ArrayLike, organic_carbon: ArrayLike, out: Mayr1999PTFResult[NDArray[floating]] | None = None) -> Mayr1999PTFResult[NDArray[floating]]

Calculate the pedotransfer function.

Estimate modified Brooks-Corey a, b, and saturated water content from texture, bulk density, and organic carbon.

PARAMETER DESCRIPTION
sand

Sand content for particles 0.063-2.0 mm. (%)

TYPE: float | ArrayLike

silt

Silt content for particles 0.002-0.063 mm. (%)

TYPE: float | ArrayLike

clay

Clay content for particles 0-0.002 mm. (%)

TYPE: float | ArrayLike

bulk_density

Dry bulk density; the paper excludes application below 0.9 g/cm^3. (g/cm^3)

TYPE: float | ArrayLike

organic_carbon

Organic carbon content; the paper excludes application above 5%. (%)

TYPE: float | ArrayLike

out

Optional output arrays for in-place calculation.

TYPE: Mayr1999PTFResult[NDArray[floating]] | None DEFAULT: None

RETURNS DESCRIPTION
Mayr1999PTFResult

Results grouped by result attributes.

TYPE: Mayr1999PTFResult[floating] | Mayr1999PTFResult[NDArray[floating]]

Models

\(h(\theta)\): Hutson-Cass modified Brooks-Corey water-retention model

Notes

Prediction target: Hutson-Cass modified Brooks-Corey water-retention parameters a, b, and saturated volumetric water content. The particle-size inputs use the UK size boundaries stated by the paper; sand, silt, and clay are percentages. The source reports r^2 values of 0.34 for log(a), 0.74 for log(1/b), and 0.84 for theta_s. Human review resolved the source's unspecified log base as base 10; the implementation therefore interprets log(a) and log(1/b) as log10 values.

Warning

Do not apply the functions to organic soils with organic carbon above 5% or soils with dry bulk density below 0.9 g/cm^3. Treat application outside the calibration particle-size distribution with great care; the paper provides that distribution only graphically.

Source code in ptfkit/mayr1999.py 
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def calc_ptf_mayr1999(
    *,
    sand: float | ArrayLike,
    silt: float | ArrayLike,
    clay: float | ArrayLike,
    bulk_density: float | ArrayLike,
    organic_carbon: float | ArrayLike,
    out: Mayr1999PTFResult[NDArray[floating]] | None = None,
) -> Mayr1999PTFResult[floating] | Mayr1999PTFResult[NDArray[floating]]:
    r"""Calculate the pedotransfer function.

    Estimate modified Brooks-Corey a, b, and saturated water content from texture, bulk density, and
    organic carbon.

    Arguments:
        sand: Sand content for particles 0.063-2.0 mm. (%)
        silt: Silt content for particles 0.002-0.063 mm. (%)
        clay: Clay content for particles 0-0.002 mm. (%)
        bulk_density: Dry bulk density; the paper excludes application below 0.9 g/cm^3. (g/cm^3)
        organic_carbon: Organic carbon content; the paper excludes application above 5%. (%)
        out: Optional output arrays for in-place calculation.

    Returns:
        Mayr1999PTFResult: Results grouped by result attributes.

    Models:
        $h(\theta)$: Hutson-Cass modified Brooks-Corey water-retention model

    Notes:
        Prediction target: Hutson-Cass modified Brooks-Corey water-retention parameters a, b, and
            saturated volumetric water content.
        The particle-size inputs use the UK size boundaries stated by the paper; sand, silt, and
            clay are percentages.
        The source reports r^2 values of 0.34 for log(a), 0.74 for log(1/b), and 0.84 for theta_s.
        Human review resolved the source's unspecified log base as base 10; the implementation
            therefore interprets log(a) and log(1/b) as log10 values.

    Warning:
        Do not apply the functions to organic soils with organic carbon above 5% or soils with dry
            bulk density below 0.9 g/cm^3.
        Treat application outside the calibration particle-size distribution with great care; the
            paper provides that distribution only graphically.

    """
    values = _call(
        _calc_ptf_mayr1999,
        sand,
        silt,
        clay,
        bulk_density,
        organic_carbon,
        out=out,
    )

    return Mayr1999PTFResult(*values)