Delta-T HH2 - Water Deficit Calculations

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Water Deficit Explained Moisture Meter User Manual 4.0
Deficit vs Water Content
-20
-10
0
10
20
30
40
50
0 0.2 0.4 0.6 0.8 1
Soil Moisture Content (m3.m-3)
Deficit (mm)
Available Water Capacity is the difference between Field Capacity and Wilting
Point.
Water Deficit is the amount of irrigation water or rainfall (mm) that has to be
added to a soil profile in order to bring it back up to field capacity.
The size of the water deficit will depend on the depth of the soil profile that it relates
to (usually taken as some function of the crop rooting depth).
This example shows
deficit versus water
content for a shallow
sandy clay loam.
Water Deficit Calculation for ThetaProbes
Water Deficit is calculated using the formula
D = R * (FWC - VWC)
where
R =
Rooting depth
FWC =
Field water capacity
VWC =
Calculated volumetric water content