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Guideline
for Estimating Soil Moisture
Available Water Holding Capacity of Various Textured Soils:
Available
Water Capacity, AWC (Inches/Foot)
AWC |
Coarse Texture
Fine Sand and Loamy Fine Sand |
Moderately Coarse Texture - Sandy Loam and Fine Sandy Loam |
Medium Texture - Sandy Clay Loam, Loam, and Silt Loam |
Fine Texture-Clay, Clay Loam, or Silty Clay Loam |
Range |
0.6 - 1.2 |
1.3 - 1.7 |
1.5 - 2.1 |
1.6 - 2.4
|
Soil Moisture Deficits (SMD) in inches/foot based on described soil
appearance:
Soil Moisture Deficits
| AvailableSoil Moisture Percent |
Coarse Texture
Fine Sand and Loamy Fine Sand |
Moderately Coarse Texture- Sandy Loam and Fine Sandy Loam |
Medium Texture - Sandy Clay Loam, Loam, and Silt Loam |
Fine Texture-Clay, Clay Loam, or Silty Clay Loam |
|
0 - 25 |
Dry,loose, will hold together if not disturbed, loose sand grains on fingerswith applied pressure.
SMD 1.2-0.5
|
Dry,
forms a very weak ball, aggregated soil grains break away easily from
ball.
SMD 1.7 -1.0
|
Dry.
Soil aggregations break away easily. no moisture staining on fingers,
clods crumble with applied pressure.
SMD 2.1-1.1
|
Dry,
soil aggregations easily separate, clods are hard to crumble with
applied pressure
SMD 2.4-1.2
|
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25
- 50
|
Slightly
moist, forms a very weak ball with well-defined finger marks, light
coating of loose and aggregated sand grains remain on fingers.
SMD O.9-0.3
|
Slightly
moist, forms a weak ball with defined finger marks, darkened color, no
water staining on fingers, grains break away.
SMD 1.3-0.7
|
Slightly
moist, forms a weak ball with rough surfaces, no water staining on
fingers, few aggregated soil grains break away.
SMD1.6-0.8
|
Slightly
moist, forms a weak ball, very few soil aggregations break away, no
water stains, clods flatten with applied pressure
SMD 1.8-0.8
|
|
50
- 75
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Moist,
forms a weak ball with loose and aggregated sand grains on fingers,
darkened color, moderate water staining on fingers, will not ribbon.
SMD O.6-0.2
|
Moist,
forms a ball with defined finger marks. very light soil/water staining
on fingers. darkened color, will not slick.
SMD O.9-0.3
|
Moist,
forms a ball, very light water staining on fingers, darkened color,
pliable, forms a weak ribbon between thumb and forefinger.
SMD 1.1- 0.4
|
Moist.
forms a smooth ball with defined finger marks, light soil/water staining
on fingers, ribbons between thumb and forefinger.
SMD l.2-0.4
|
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75
- 100
|
Wet,
forms a weak ball, loose and aggregated sand grains remain on fingers,
darkened color, heavy water staining on fingers, will not ribbon.
SMD O.3-0.0
|
Wet,
forms a ball with wet outline left on hand, light to medium water
staining on fingers, makes a weak ribbon between thumb and forefinger.
SMD O.4-0.0
|
Wet,
forms a ball with well defined finger marks, light to
heavy soil/water coating on fingers, ribbons between , thumb and
forefinger.
SMD O.5 -0.0
|
Wet,
forms a ball, uneven medium to heavy soil/water coating on fingers,
ribbons easily between thumb and forefinger.
SMD O.6-0.0
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Field
Capacity (100%)
|
Wet, forms a
weak ball, moderate to heavy soil/water coating on fingers, wet outline
of soft ball remains on hand.
SMD 0.0
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Wet,
forms a soft ball, free water appears briefly on soil surface after
squeezing or shaking,medium to heavy soil/water coating on fingers.
SMD 0.0
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Wet,
forms a soft ball, free water appears briefly on soil surface after
squeezing or shaking, medium to heavy soil/water coating on fingers.
SMD 0.0
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Wet,
forms a soft ball, free water appears on soil surface after squeezing or
shaking, thick soil/water coating on fingers, slick and sticky.
SMD 0.0
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