Soil and Beds
Available Soil Water Calculator
Planning available water starts with consistent values for field capacity and wilting point. This calculator performs that arithmetic.
Enter values for available water
Replace the Available Soil Water examples before using available water.
Available Soil Water in practical terms
The planning question for Available Soil Water is whether you can find the water fraction held between field capacity and wilting point. Available Soil Water measures this portion as Available water.
Record adjustments outside Available water separately.
Available Soil Water assumption to check
Laboratory percentages must use the same mass or volume basis.
For Available Soil Water, verify the basis of Field capacity and Wilting point. Similar percentages can describe different totals.
Measurements for Available Soil Water
The Available Soil Water input panel defines Field capacity and Wilting point. Note any Available Soil Water conversion.
- Field capacity
- Available Soil Water enters 32% for this percentage.
- Wilting point
- Available Soil Water enters 14% for this percentage.
Formula for available water
Available Soil Water finds the difference using Field capacity and Wilting point.
Using field capacity at 32% and wilting point at 14%, the example returns 18.00 percentage points and 128.6%.
Available water: interpretation
Use Available water to find the water fraction held between field capacity and wilting point. Keep the Available Soil Water inputs beside the output.
Available water above wilting point supplements available water in Available Soil Water.
Testing a change in field capacity
To compare alternatives, save the current result before changing Field capacity. Label both cases so the source measurements remain clear.
Testing the available water response
In a Available Soil Water sensitivity check, compare field capacity at 32% and 35.2%. Available water evaluates to 18.00 percentage points and 21.20 percentage points, respectively. Soil Moisture Deficit Calculator calculates moisture deficit separately.
Both cases hold wilting point unchanged; preserve the other Available Soil Water inputs too.
Prefer measured field capacity ranges in Available Soil Water.
Common questions about field capacity
How does “Laboratory percentages must use the same mass or volume basis.” affect available water?
Available Soil Water uses the entered numbers only. Let field capacity reflect that condition before calculating.
How much soil variation can Available Soil Water show?
Only variation captured by the entered measurements. Several zones may need separate available water cases.
Should Field capacity be written as 25 or 0.25?
Type 25 when Field capacity is 25 percent in Available Soil Water.