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ptfkit.dijkerman1988

ptfkit.dijkerman1988

Dijkerman (1988), texture-based gravimetric water retention for Sierra Leone soils.

Reference

Dijkerman, J. C. (1988). An Ustult-Aquult-Tropept catena in Sierra Leone, West Africa, II. Land qualities and land evaluation. Geoderma, 42, 29-49. DOI: 10.1016/0016-7061(88)90021-3

Territory

Sierra Leone, West Africa

Dataset

166 soil samples from 42 soil profiles reported by Odell et al. (1974). Samples with organic carbon greater than 4% were excluded from the regressions.

CLASS DESCRIPTION
Dijkerman1988WaterContent

Results returned by the matching PTF.
FUNCTION DESCRIPTION
calc_ptf_dijkerman1988

Estimate gravimetric water contents at 15 bar and one-third bar from texture.
calc_ptf_dijkerman1988_available_water

Estimate the gravimetric available moisture between one-third bar and 15 bar.

Dijkerman1988WaterContent

Bases: NamedTuple, Generic[T]

Results returned by the matching PTF.

ATTRIBUTE DESCRIPTION
water_content_15_bar

Gravimetric moisture content at 15 bar, in weight percentage. (%)

TYPE: T

water_content_one_third_bar

Gravimetric moisture content at one-third bar, in weight percentage. (%)

TYPE: T

Source code in ptfkit/dijkerman1988.py 
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class Dijkerman1988WaterContent(NamedTuple, Generic[T]):
    """Results returned by the matching PTF.

    Attributes:
        water_content_15_bar: Gravimetric moisture content at 15 bar, in weight percentage. (%)
        water_content_one_third_bar: Gravimetric moisture content at one-third bar, in weight
            percentage. (%)

    """

    water_content_15_bar: T
    water_content_one_third_bar: T

calc_ptf_dijkerman1988 

calc_ptf_dijkerman1988(*, clay: float, sand: float) -> Dijkerman1988WaterContent[floating]

calc_ptf_dijkerman1988(*, clay: ArrayLike, sand: ArrayLike, out: Dijkerman1988WaterContent[NDArray[floating]] | None = None) -> Dijkerman1988WaterContent[NDArray[floating]]

Estimate gravimetric water contents at 15 bar and one-third bar from texture.

PARAMETER DESCRIPTION
clay

Clay content by mass. The supplied research notes report this observed calibration range from a reconstruction of Odell et al. (1974), Appendix B. (%)

TYPE: float | ArrayLike

sand

Sand content by mass. The supplied research notes report this observed calibration range from a reconstruction of Odell et al. (1974), Appendix B. (%)

TYPE: float | ArrayLike

out

Optional output arrays for in-place calculation.

TYPE: Dijkerman1988WaterContent[NDArray[floating]] | None DEFAULT: None

RETURNS DESCRIPTION
Dijkerman1988WaterContent

Results grouped by result attributes.

TYPE: Dijkerman1988WaterContent[floating] | Dijkerman1988WaterContent[NDArray[floating]]

Notes

Prediction target: Gravimetric water contents at 15 bar and one-third bar. Sand, silt, and clay percentages must sum to 100; sand plus clay must not exceed 100. The regression dataset excludes samples containing more than 4% organic carbon. These are two point predictions, not a continuous retention curve.

Warning

The paper describes these relationships as rough guides. One-third-bar moisture content may underestimate field capacity and available moisture in these soils. The observed marginal calibration ranges do not establish validity for every joint texture combination.

Source code in ptfkit/dijkerman1988.py 
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def calc_ptf_dijkerman1988(
    *,
    clay: float | ArrayLike,
    sand: float | ArrayLike,
    out: Dijkerman1988WaterContent[NDArray[floating]] | None = None,
) -> Dijkerman1988WaterContent[floating] | Dijkerman1988WaterContent[NDArray[floating]]:
    """Estimate gravimetric water contents at 15 bar and one-third bar from texture.

    Arguments:
        clay: Clay content by mass. The supplied research notes report this observed calibration
            range from a reconstruction of Odell et al. (1974), Appendix B. (%)
        sand: Sand content by mass. The supplied research notes report this observed calibration
            range from a reconstruction of Odell et al. (1974), Appendix B. (%)
        out: Optional output arrays for in-place calculation.

    Returns:
        Dijkerman1988WaterContent: Results grouped by result attributes.

    Notes:
        Prediction target: Gravimetric water contents at 15 bar and one-third bar.
        Sand, silt, and clay percentages must sum to 100; sand plus clay must not exceed 100.
        The regression dataset excludes samples containing more than 4% organic carbon.
        These are two point predictions, not a continuous retention curve.

    Warning:
        The paper describes these relationships as rough guides.
        One-third-bar moisture content may underestimate field capacity and available moisture in
            these soils.
        The observed marginal calibration ranges do not establish validity for every joint texture
            combination.

    """
    values = _call(
        _calc_ptf_dijkerman1988,
        clay,
        sand,
        out=out,
    )

    return Dijkerman1988WaterContent(*values)

calc_ptf_dijkerman1988_available_water 

calc_ptf_dijkerman1988_available_water(*, clay: float, silt: float) -> floating

calc_ptf_dijkerman1988_available_water(*, clay: ArrayLike, silt: ArrayLike, out: NDArray[floating] | None = None) -> NDArray[floating]

Estimate the gravimetric available moisture between one-third bar and 15 bar.

PARAMETER DESCRIPTION
clay

Clay content by mass. The supplied research notes report this observed calibration range from a reconstruction of Odell et al. (1974), Appendix B. (%)

TYPE: float | ArrayLike

silt

Silt content by mass; sand, silt, and clay sum to 100%. No separate observed silt calibration range is supplied. (%)

TYPE: float | ArrayLike

out

Optional output arrays for in-place calculation.

TYPE: NDArray[floating] | None DEFAULT: None

RETURNS DESCRIPTION
available_water

Difference in gravimetric moisture contents, in weight percentage points. (%)

TYPE: floating | NDArray[floating]

Notes

Prediction target: Gravimetric available moisture between one-third bar and 15 bar. This estimates a gravimetric difference, not profile water storage or a volumetric fraction. Use soil material with organic carbon at most 4% and physically consistent texture percentages.

Warning

Available moisture estimated using one-third bar may be somewhat low according to the paper.

Source code in ptfkit/dijkerman1988.py 
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def calc_ptf_dijkerman1988_available_water(
    *,
    clay: float | ArrayLike,
    silt: float | ArrayLike,
    out: NDArray[floating] | None = None,
) -> floating | NDArray[floating]:
    """Estimate the gravimetric available moisture between one-third bar and 15 bar.

    Arguments:
        clay: Clay content by mass. The supplied research notes report this observed calibration
            range from a reconstruction of Odell et al. (1974), Appendix B. (%)
        silt: Silt content by mass; sand, silt, and clay sum to 100%. No separate observed silt
            calibration range is supplied. (%)
        out: Optional output arrays for in-place calculation.

    Returns:
        available_water: Difference in gravimetric moisture contents, in weight percentage points.
            (%)

    Notes:
        Prediction target: Gravimetric available moisture between one-third bar and 15 bar.
        This estimates a gravimetric difference, not profile water storage or a volumetric fraction.
        Use soil material with organic carbon at most 4% and physically consistent texture
            percentages.

    Warning:
        Available moisture estimated using one-third bar may be somewhat low according to the paper.

    """
    return _call(
        _calc_ptf_dijkerman1988_available_water,
        clay,
        silt,
        out=out,
    )