Soil Survey of McHenry County, Illinois Part I - Soil Data Mart

McHenry County, Illinois—Part I 123
35 percent very dark grayish brown (2.5Y 3/2)
loam, dark grayish brown (10YR 4/2) dry; weak
fine and medium subangular blocky structure;
friable; common very fine roots; neutral; clear
smooth boundary.
Btg1—15 to 20 inches; dark grayish brown (2.5Y 4/2)
loam; weak medium prismatic structure parting to
moderate medium subangular blocky; friable;
common very fine roots; few distinct dark gray
(2.5Y 4/1) clay films and black (10YR 2/1) organic
coatings on faces of peds and in pores; common
fine distinct olive brown (2.5Y 4/4) masses of iron
accumulation in the matrix; common fine and
medium faint grayish brown (2.5Y 5/2) iron
depletions in the matrix; 1 percent gravel; neutral;
gradual smooth boundary.
Btg2—20 to 30 inches; grayish brown (2.5Y 5/2) clay
loam; moderate medium subangular blocky
structure; friable; common very fine roots; few
distinct dark gray (2.5Y 4/1) and grayish brown
(2.5Y 4/2) clay films on faces of peds and in
pores; common fine strong brown (7.5YR 4/6)
very weakly cemented iron oxide concretions
throughout; common fine and medium distinct light
olive brown (2.5Y 5/4) masses of iron
accumulation in the matrix; 2 percent gravel;
neutral; gradual smooth boundary.
Btg3—30 to 42 inches; light olive gray (5Y 6/2) clay
loam; weak medium and coarse subangular
blocky structure; friable; few very fine roots; few
distinct olive gray (5Y 5/2) clay films on faces of
peds and in pores; very dark gray (10YR 3/1)
krotovina; common fine strong brown (7.5YR 4/6)
very weakly cemented iron oxide concretions
throughout; common fine and medium prominent
light olive brown (2.5Y 5/4) masses of iron
accumulation in the matrix; 2 percent gravel;
neutral; clear smooth boundary.
2BCg—42 to 47 inches; grayish brown (2.5Y 5/2)
sandy loam; weak medium subangular blocky
structure; very friable; few very fine roots;
common medium and coarse distinct light olive
brown (2.5Y 5/4) masses of iron accumulation in
the matrix; 4 percent gravel; neutral; clear wavy
boundary.
2Cg—47 to 60 inches; grayish brown (2.5Y 5/2) loamy
sand; massive; very friable; common medium and
coarse prominent yellowish brown (10YR 5/6)
masses of iron accumulation in the matrix; 4
percent gravel; neutral.
MLRA Series Range in Characteristics
Thickness of the mollic epipedon: 10 to 20 inches
Depth to sandy outwash: 35 to 55 inches
Depth to carbonates: Greater than 35 inches
Thickness of the solum: 35 to 55 inches
Ap or A horizon:
Hue—10YR, 2.5Y, or N
Value—2 or 3
Chroma—0 to 2
Texture—clay loam, loam, or silt loam
Btg horizon:
Hue—10YR, 2.5Y, 5Y, or N
Value—4 to 6
Chroma—0 to 2
Texture—loam, clay loam, sandy clay loam, sandy
loam, silty clay loam, or silt loam
2Cg or 2C horizon:
Hue—10YR, 2.5Y, or 5Y
Value—5 or 6
Chroma—1 to 4
Texture—sand or loamy sand
529A—Selmass loam, 0 to 2 percent
slopes
Setting
Landform: Outwash plains and stream terraces
Position on the landform: Footslopes and toeslopes
Slope range: 0 to 2 percent
A typical soil series description with range in
characteristics is included, in alphabetical order, in this
section. Additional information specific to this map unit,
such as horizon depth and textures, is available in the
“Soil Properties” section in Part II of this publication.
Composition
Selmass and similar soils: 85 percent
Dissimilar soils: 15 percent
Similar soils:
• soils that contain less sand and more silt in the
upper and middle parts of the profile
• soils that contain sandy outwash at a depth of less
than 35 inches
• soils that have a thinner subsurface layer
• soils that contain less clay in the subsoil
Dissimilar soils:
• the well drained Dakota and somewhat poorly
drained Lahoguess soils in the higher positions on the
landform
• the calcareous Hooppole soils in positions on the
landform similar to those of the Selmass soil
• the very poorly drained Houghton and Palms soils
in depressions