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

McHenry County, Illinois—Part I 131
• “Agronomy” section
• “Wildlife Habitat” section
• “Engineering” section
• “Soil Properties” section
Varna Series
Drainage class: Moderately well drained
Permeability: Moderately slow in the upper part and
slow in the lower part
Landform: Moraines and till plains
Parent material: Thin mantle of silty material and the
underlying silty clay loam till
Slope range: 2 to 12 percent
Taxonomic classification: Fine, illitic, mesic Oxyaquic
Argiudolls
Taxadjunct features: Varna silt loam, 4 to 6 percent
slopes, eroded, and Varna silt loam, 6 to 12
percent slopes, eroded, have a mollic epipedon
that is less than 10 inches thick. These soils are
classified as fine, illitic, mesic Oxyaquic
Hapludalfs.
Typical Pedon for MLRA 95B
Typical pedon of Varna silt loam, 4 to 6 percent
slopes, eroded, 285 feet south and 2,565 feet east of
the northwest corner of sec. 19, T. 44 N., R. 7 E.
Ap1—0 to 4 inches; very dark grayish brown (10YR
3/2) silt loam, dark grayish brown (10YR 4/2) dry;
moderate fine granular structure; friable; common
very fine roots; few distinct black (10YR 2/1)
organic coatings on faces of peds; slightly acid;
abrupt smooth boundary.
Ap2—4 to 8 inches; 97 percent very dark grayish
brown (10YR 3/2) and 3 percent brown (10YR 4/3)
silty clay loam, dark grayish brown (10YR 4/2) dry;
weak medium subangular blocky structure parting
to weak medium granular; friable; common very
fine roots; common distinct black (10YR 2/1)
organic coatings on faces of peds; 1 percent
gravel; moderately acid; abrupt smooth boundary.
BA—8 to 12 inches; brown (10YR 4/3) silty clay loam;
weak fine and medium subangular blocky
structure; friable; common very fine roots; few
distinct very dark grayish brown (10YR 3/2) and
very few distinct black (10YR 2/1) organic
coatings on faces of peds and in pores; 1 percent
gravel; neutral; clear smooth boundary.
2Bt1—12 to 20 inches; brown (10YR 4/3) silty clay
loam; moderate fine and medium subangular
blocky structure; friable; common very fine roots;
common distinct dark brown (10YR 3/3) clay films
on faces of peds; few distinct very dark grayish
brown (10YR 3/2) organic coatings on faces of
peds and in pores; 1 percent gravel; neutral; clear
smooth boundary.
2Bt2—20 to 25 inches; olive brown (2.5Y 4/3) silty clay
loam; moderate fine prismatic structure parting to
moderate fine and medium subangular blocky;
friable; common very fine roots; common distinct
dark grayish brown (2.5Y 4/2) clay films on faces
of peds; very few distinct very dark grayish brown
(10YR 3/2) organic coatings in root channels and
in pores; 1 percent gravel; neutral; clear smooth
boundary.
2Bt3—25 to 31 inches; light olive brown (2.5Y 5/4)
silty clay loam; moderate medium prismatic
structure parting to moderate medium subangular
blocky; firm; common very fine roots; few distinct
grayish brown (2.5Y 5/2) and very few distinct
dark grayish brown (2.5Y 4/2) clay films on faces
of peds; common fine prominent yellowish brown
(10YR 5/6) masses of iron accumulation in the
matrix; common fine distinct light brownish gray
(2.5Y 6/2) iron depletions in the matrix; 3 percent
gravel; strongly effervescent; slightly alkaline;
clear smooth boundary.
2BC—31 to 36 inches; light olive brown (2.5Y 5/4) silty
clay loam; weak medium prismatic structure
parting to weak medium subangular blocky; firm;
common very fine roots; common fine and
medium white (10YR 8/1) soft masses of
carbonates; common fine yellowish brown (10YR
5/8) very weakly cemented iron oxide concretions
throughout; few fine black (7.5YR 2/1) very weakly
cemented iron and manganese oxide concretions
throughout; many fine and medium prominent
yellowish brown (10YR 5/6) masses of iron
accumulation in the matrix; many fine and medium
distinct light brownish gray (2.5Y 6/2) iron
depletions in the matrix; 3 percent gravel; strongly
effervescent; moderately alkaline; gradual smooth
boundary.
2C—36 to 60 inches; light olive brown (2.5Y 5/4) silty
clay loam; massive; very firm; common fine white
(10YR 8/1) carbonate nodules; few fine yellowish
brown (10YR 5/8) very weakly cemented iron
oxide concretions throughout; common fine and
medium prominent yellowish brown (10YR 5/6)
masses of iron accumulation in the matrix; many
medium distinct gray (2.5Y 6/1) iron depletions in
the matrix; 3 percent gravel; violently effervescent;
moderately alkaline.
MLRA Series Range in Characteristics
Thickness of the mollic epipedon: 10 to 16 inches
Thickness of silty material: Less than 18 inches