LOCATION PRUDY IDEstablished Series
The Prudy series consists of deep, well drained soils that formed in
mixed colluvium over calcareous quartzite residuum. Prudy soils are on
mountainsides and have slopes of 30 to 60 percent. Permeability is
moderate. The average annual precipitation is about 18 inches and the
average annual air temperature is about 39 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Calcic Haplocryolls
TYPICAL PEDON: Prudy loam on a 45 percent slope at an elevation of
5,100 feet in rangeland. When described on May 17, 1983, the soil was
moist throughout. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; dark grayish brown (10YR 4/2) loam, very dark
grayish brown (10YR 3/2) moist; moderate fine granular structure; soft,
friable, slightly sticky and slightly plastic; many very fine and fine
roots; many very fine and fine interstitial pores and common very fine
and fine tubular pores; about 5 percent pebbles; mildly alkaline (pH
7.6); clear smooth boundary (2 to 4 inches thick)
A2--3 to 10 inches; dark brown (10YR 4/3) loam, very dark grayish
brown (10YR 3/2) moist; weak fine and medium subangular blocky
structure; soft, friable, slightly sticky and slightly plastic; many
very fine and fine roots and few medium and coarse roots; many very fine and fine tubular pores; about 5 percent gravel; mildly alkaline (pH 7.6); gradual smooth boundary. (5 to 9 inches thick)
BAk--10 to 14 inches; brown (10YR 4/3) loam, dark brown (10YR 3/3)
moist; weak medium and coarse subangular blocky structure; slightly
hard, friable, slightly sticky and plastic; many very fine and fine
roots; common very fine and fine tubular pores; about 10 percent
pebbles; strong effervescence (15 to 25 percent calcium carbonate);
mildly alkaline (pH 7.8); clear smooth boundary. (0 to 5 inches thick)
Bk1--14 to 21 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3)
moist; moderate medium subangular blocky structure; hard, firm, sticky
and plastic; many very fine and fine, few medium roots; common very fine and fine tubular pores; about 10 percent pebbles; violent effervescence (25 to 40 percent calcium carbonate); moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 10 inches thick)
Bk2--21 to 25 inches; pale brown (10YR 6/3) gravelly loam, brown
(10YR 5/3) moist; moderate medium subangular blocky structure; hard,
firm, slightly sticky and plastic; common very fine, fine, and medium
roots; common very fine and fine tubular pores; about 30 percent
pebbles; violent effervescence (25 to 40 percent calcium carbonate);
moderately alkaline (pH 8.4); gradual wavy boundary. (3 to 8 inches
thick)
Bk3--25 to 42 inches; very pale brown (10YR 7/3) gravelly loam, pale brown (10YR 6/3) moist; weak medium subangular blocky structure;
slightly hard, friable, slightly sticky and slightly plastic; few fine
and medium roots; few very fine and fine tubular pores; about 10 percent cobbles and 20 percent pebbles; violent effervescence (25 to 40 percent calcium carbonate); strongly alkaline (pH 8.6); abrupt smooth boundary. (10 to 20 inches thick)
2Bqkm--42 to 50 inches; white (10YR 8/2) indurated duripan, very
pale brown (10YR 7/4) moist; massive or in places strong medium platy
structure; few fine and medium roots matted on top of duripan; about 10
percent cobbles and 25 percent pebbles cemented in place; violent
effervescence (25 to 40 percent calcium carbonate); strongly alkaline
(pH 8.6); abrupt smooth boundary. (4 to 10 inches thick)
2R--50 inches; fractured calcareous quartzite bedrock with Bqkm
material in fractures.
TYPE LOCATION: Blaine County, Idaho; about 3.5 miles south and 0.5
miles east of Gannett; 1400 feet south and 400 feet west of the
northeast corner of section 26, T. 1 S., R. 19 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 43 degrees F.
Thickness of mollic epipedon - 10 to 15 inches
Depth of indurated duripan - 40 to 48 inches
Depth to bedrock - 50 to 60 inches
Depth to calcic horizon - 12 to 21 inches
2Bkq horizon - may be present in some pedons
A horizon
Value- 4 or 5 dry, 2 or 3 moist
Chroma- moist or dry, 2 or 3
Reaction - neutral to mildly alkaline
Effervescence - noneffervescent to slightly effervescent
BAk horizon
Value- 4 to 6 dry, 2 or 3 moist
Chroma- 2 or 3 dry or moist
Reaction - mildly alkaline to moderately alkaline
Effervescence - slight to strong effervescence
Rock fragments - 5 to 20 percent gravel
Clay content - 18 to 24 percent
Bk horizons
Value- 5 through 7 dry, 5 or 6 moist
Chroma- 3 or 4 dry or moist
Reaction - moderately alkaline to strongly alkaline
Effervescence - strong to violent effervescence
Rock fragments - 0 to 10 percent cobbles; 10 to 20 percent gravel
Clay content - 20 to 27 percent
Texture - L, GR-L, or GR-FSL
2Bqkm horizon
Value- 7 or 8 dry, 6 or 7 moist
Chroma- 2 through 4 moist or dry
Rock fragments - 5 to 10 percent cobbles; 20 to 30 percent gravel
Structure - massive or platty
Laminar capping - continuous, 1 to 3 mm thick
Duripan - indurated
COMPETING SERIES: There are no series in this family. Escarlo soils
are similar. Escarlo soils have carbonatic minerology.
GEOGRAPHIC SETTING: Prudy soils are on mountainsides. Slopes range
from 30 to 60 percent. Elevation ranges from 4,700 to 6,000 feet. The
soils formed from colluvium over residuum derived dominantly from
calcareous quartzite. The average annual precipitation is 16 to 20
inches, most of which falls as snow and early spring rain. The average
annual air temperature is 37 to 41 degrees F. The frost-free season is
30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackspot, Elksel,
Furshur, Friedman, Peeveywell, and Winridge soils. Blackspot soils are
10 to 20 deep to a duripan. Elksel soils have more than 35 percent rock fragments and more than 35 percent clay in the control section. Furshur soils have more than 35 percent clay in the control section and are 10 to 20 deep to a duripan. Friedman soils have Pachic epipedons.
Peeveywell soils are moderately deep to a duripan and contain more than
35 percent clay in the control section. Winridge soils are moderately
deep and have more than 35 percent clay in the control section.
Blackspot soils occur on the same landscape. Elksel, Furshur, Hamtah,
Peeveywell, and Winridge soils occur on mountainsides formed from
tertiary volcanics.
DRAINAGE AND PERMEABILITY: Well drained; rapid to very rapid runoff;
moderate permeability.
USE AND VEGETATION: Mainly used for rangeland. Vegetation is mountain
big sagebrush, bluebunch wheatgrass, snowberry, and Idaho fescue.
DISTRIBUTION AND EXTENT: Prudy soils are inextensive in south central
Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Blaine County, Idaho, 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the soil surface to about 14 inches (A1, A2, and BAk horizons)
Calcic horizon - zone from 14 to 42 inches (BAk, Bk1, Bk2, and Bk3
horizons)
Particle - size control section - 10 to 40 inches (BAk, Bk1, Bk2, and
part of Bk3 horizons)
Duripan over bedrock: Occurs immediately below the calcic horizon but
below a depth of 1 meter.
National Cooperative Soil Survey