Soils Genesis and Characterization

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Soils Genesis and Characterization
Department of Agricultural and Biological
Engineering
University of Illinois at Urbana-Champaign
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95BSouthern Wisconsin and Northern Illinois
Drift Plain 98Southern Michigan and Northern
Indiana Drift Plain 105Northern Mississippi
Valley Loess Hills 108A and 108BIllinois and
Iowa Deep Loess and Drift 110Northern Illinois
and Indiana Heavy Till Plain 113Central Claypan
Areas 114BSouthern Illinois and Indiana Thin
Loess and Till Plain, Western Part 115A, 115B,
and 115CCentral Mississippi Valley Wooded
Slopes 120BKentucky and Indiana Sandstone and
Shale Hills and Valleys, Northwestern
Part 131ASouthern Mississippi River
Alluvium 134Southern Mississippi Valley Loess
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Typical cross section showing the relationship of
parent materials to soils in Cass County.
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Soils Occur in Associations
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Sable-Ipava Soil Association
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Sable Silty Clay Loam
This poorly drained "prairie soil" formed in more
than 60 inches of loess. There are about 925,000
acres mapped in Illinois. It has a PI of 155.
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Typical pattern of soils and parent material in
the Drummer-Flanagan association.
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Drummer Silty Clay Loam
This poorly drained "prairie soil" formed in 40
to 60 inches of loess over Wisconsinan drift. It
occupies nearly 1.6 million acres. It has a high
management level productivity index (PI) of 150.
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Typical pattern of soils and parent material in
the Hoyleton-Cisne association.
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Cisne Silt Loam
This poorly drained "gray prairie soil" formed in
30 to 55 inches of loess over Illinoian drift.
About 730,000 acres occur in south central
Illinois. It has a PI of 115.
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Typical pattern of soils and parent material in
the Titus-Beaucoup-Tice association.
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Soil Constituents
Solid Particles
Soil Solution
Air
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Saturated (all pores filled)?
(Some air, some water)?
Field Capacity
Wilting point (water too tightly held for plant
use)?
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Hydroscopic Water
Gravitational Water
Capillary Water
Water held in large pores Available for crop use
Water adheres to soil particles
Water drains through soil profile
Wilting Point
Field Capacity
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Flowing Tile Positive Pressure i.e.
Saturation must occur above tile drains for
water to enter.
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Classification of Particles
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Simplified Soil Texture Triangle
Soils with more than 30 clay are Clays Soils
with 20 - 30 clay are Clay Loams Soils with
less than 20 clay are Loams unless they have
more than 80 sand Soils with more than 80 sand
are Sands Soils with more than 50 sand are
Sandy Soils with more than 50 silt are Silty
Sable
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Water States by Soil Texture
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Classification by Permeability
More than 6 inches per hour
Rapidly permeable
1
2 to 6 inches per hour
Moderately rapidly permeable
0.6 to 2 inches per hour
Moderately permeable
2
0.2 to 0.6 inch per hour
Moderately slowly permeable
3
0.06 to 0.2 inch per hour
Slowly permeable
4
less than 0.06 inch per hour
Very slowly permeable
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Classification by Natural Drainage
The water table is at or near the surface during
the wetter seasons of the year
Poorly drained
A
The water table remains near, at, or above the
surface much of the time
Very poorly drained
The water table is near the surface only during
the very wettest periods
Somewhat poorly drained
B
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Soil Drainage Groups

• DRAINAGE GROUP 4A
• (slowly and very slowly permeable, poorly or very
  poorly drained)

287 Chauncey
165 Weir
84 Okaw
2 Cisne
460 Ginat
206 Thorp
109 Racoon
12 Wynoose
474 Piasa
208 Sexton
112 Cowden
16 Rushville
576 Zwingle
218 Newberry
120 Huey
26 Wagner
633 Traer
261 Niota
136 Brooklyn
45 Denny

• DRAINAGE GROUP 2A
• (moderately permeable, poorly or very poorly
  drained)

594 Reddick
244 Hartsburg
142 Patton
67 Harpster
648 Clyde
252 Harvel
152 Drummer
68 Sable
316 Romeo
329 Will
153 Pella
125 Selma
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A cube of soil measures 10 x 10 x 10 cm and has a
total (wet) mass of 1460 g, of which 260 g is
water. Determine the volumetric water content,
soil porosity, and degree of saturation.
Volumetric water content Volume of soil
10x10x10 1000 cm3 Volume of water mass of
water/density of water 260 (g) /1 (g/cm3)
260 cm3 Volumetric water content volume of
water/volume of soil 260/1000 0.26
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A cube of soil measures 10 x 10 x 10 cm and has a
total (wet) mass of 1460 g, of which 260 g is
water. Determine the volumetric water content,
soil porosity, and degree of saturation.
Porosity Mass of solids wet mass of soil
mass of water 1460 260 1200 g Volume of
solids mass of solids/density of solids
1200 (g) / 2.65 (g/cm3) 452.8 cm3 Volume of
fluids total volume volume of solids 1000
452.8 547.2 cm3 Porosity volume of
fluids/volume of soil 547/1000 0.55
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A cube of soil measures 10 x 10 x 10 cm and has a
total (wet) mass of 1460 g, of which 260 g is
water. Determine the volumetric water content,
soil porosity, and degree of saturation.
Degree of Saturation Degree of saturation
volume of water/volume of fluids 260/547
0.475 47.5
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A bucket contains 22 kg of soil for which the
gravimetric water content (mass of water/mass of
solids) was found to be 0.18. Determine the
volume of water in the bucket..
Gravimetric water content mass of water/mass of
solids 0.18 mass of water/(22 mass of
water) mass of water 22 x 0.18 0.18 mass of
water 1.18 mass of water 3.96 kg mass of
water 3960 (g) /1.18 3356 g Volume
of water mass of water/density of water
3356 (g) /1 (g/cm3) 3356 cm3
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A 90 cm soil column has a volumetric water
content of 0.12. Determine the quantity of water
that must be added to bring the volumetric water
content up to 0.30
Required volume (depth) of water 90 x
0.3 27 cm Current volume (depth) of
water 90 x 0.12 10.8 cm Additional
volume (depth) of water 27 10.8 16.2
cm
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Determine the gravity drainable volume (depth)
and the plant-available soil water storage
capacity in the following soil from Logan County,
Illinois. (Porosity 1 dry bulk density/2.65)
Depth (cm) Dry Bulk Density (g/cm3) Volumetric Water Content Volumetric Water Content  
Depth (cm) Dry Bulk Density (g/cm3) 1/3 bar () 15 bar () 15 bar ()
0-18 1.30 24.1 10.7 10.7
18-38 1.44 26.1 12.3 12.3
38-51 1.53 26.3 15.2 15.2
51-66 1.65 29.9 18.9 18.9
66-94 1.60 28.8 17.6 17.6
94-130 1.61 24.4 12.8 12.8
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Determine the gravity drainable volume (depth)
and the plant-available soil water storage
capacity in the following soil from Logan County,
Illinois. (Porosity 1 dry bulk density/2.65)

• Plant available water
• (cm)

• 1/3 bar
• w.c.
• 15 bar water content

• Gravity drainable volume
• (cm)

• Gravity drainable porosity
• ()

• Porosity
• ()

• Depth Increment
• (cm)

• Depth
• (cm)

4.34
24.1
4.84
26.9
51
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0-18
5.22
26.1
3.98
19.9
46
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18-38
3.42
26.3
2.04
15.7
42
13
38-51
4.49
29.9
1.22
8.1
38
15
51-66
8.06
28.8
3.14
11.2
40
28
66-94
6.34
24.4
3.80
14.6
39
26
94-130
Sum 31.87
Sum 19.02