Agriculture Soil Water Holding Capacity

Integrate measured layer field-capacity minus wilting-point water with explicit root accessibility; differs from soil porosity or gross field-capacity storage and no crop rooting depth is inferred.

Description

Root-accessible available water is the difference between field-capacity and wilting-point storage integrated through layers.

Root-accessible available water is the difference between field-capacity and wilting-point storage integrated through layers. It differs from total pore water or storage at field capacity alone.^{[1, 2]}

Integrate measured layer field-capacity minus wilting-point water with explicit root accessibility; differs from soil porosity or gross field-capacity storage and no crop rooting depth is inferred.

When to use Agriculture Soil Water Holding Capacity

Use this tool to integrate measured layer field-capacity minus wilting-point water with explicit root accessibility; differs from soil porosity or gross field-capacity storage and no crop rooting depth is inferred.

Prepare the field, crop, soil or material measurements for the intended period. Confirm units, dry/wet bases and supplied parameters; keep paired observations aligned.

How to use Agriculture Soil Water Holding Capacity and understand its results

Prepare the field, crop, soil or material measurements for the intended period. Confirm units, dry/wet bases and supplied parameters; keep paired observations aligned.
Enter layerThicknessesM, fieldCapacityVolumetricFractions, wiltingPointVolumetricFractions, accessibleRootFractions using the field table and calculation rules, then run the tool.
Read layerAccessibleAvailableWaterMm, rootAccessibleAvailableWaterMm. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
layerThicknessesM	Layer thicknesses m	list of number	Required
fieldCapacityVolumetricFractions	Field capacity volumetric fractions	list of number	Required
wiltingPointVolumetricFractions	Wilting point volumetric fractions	list of number	Required
accessibleRootFractions	Accessible root fractions	list of number	Required

Pair positive layer thicknesses in m with field-capacity, wilting-point and root-accessibility fractions in [0,1]. Field capacity cannot be below wilting point. Return available accessible mm per layer and their sum; zero difference or zero accessibility contributes zero.

Paired lists must be nonempty and have equal lengths.

layerMm = 1000 thicknessM(fieldCapacity−wiltingPoint)accessibleFraction

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
layerAccessibleAvailableWaterMm	Layer accessible available water mm	list of number
rootAccessibleAvailableWaterMm	Root accessible available water mm	number

json

{
  "input": {
    "layerThicknessesM": [
      0.1,
      0.2
    ],
    "fieldCapacityVolumetricFractions": [
      0.3,
      0.4
    ],
    "wiltingPointVolumetricFractions": [
      0.1,
      0.2
    ],
    "accessibleRootFractions": [
      1,
      0.5
    ]
  },
  "output": {
    "layerAccessibleAvailableWaterMm": [
      20,
      20
    ],
    "rootAccessibleAvailableWaterMm": 40
  }
}

Limitations and assumptions

Measured water fractions and accessible rooting are supplied. Layer overlap, changing roots, salinity and hydraulic limitations are not inferred, and no crop-specific rooting depth is chosen.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Agriculture Water Stress Coefficient Ks: Evaluate named FAO-style root-zone depletion stress coefficient with caller readily available fraction; assumes known accessible TAW/depletion and does not diagnose actual plant health or choose irrigation timing. For a complementary task, use Agriculture Irrigation Water Requirement: Balance caller interval crop demand with already-effective rainfall and planned available soil-storage draw, then convert to gross irrigation by supplied efficiency; no storage draw beyond caller availability or irrigation scheduling recommendation.

Further background: ETc under soil water stress conditions.

References

Agriculture Soil Water Holding Capacity — tool.io
ETc under soil water stress conditions — FAO

Similar or alternative tools

Agriculture Water Stress Coefficient Ks
Evaluate named FAO-style root-zone depletion stress coefficient with caller readily available fraction; assumes known accessible TAW/depletion and does not diagnose actual plant health or choose irrigation timing.
Agriculture Irrigation Water Requirement
Balance caller interval crop demand with already-effective rainfall and planned available soil-storage draw, then convert to gross irrigation by supplied efficiency; no storage draw beyond caller availability or irrigation scheduling recommendation.