LOCATION NIBBS IDEstablished Series
The Nibbs series consists of very deep, well drained, moderately
permeable soils on coalesced fan terraces. They formed in mixed
alluvium of quartz latite and quartzite with some loess influence.
Slope ranges from 2 to 8 percent. The average annual temperature is
about 46 degrees F. and the average annual precipitation is about 11
inches.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Xeric Haplocambids
TYPICAL PEDON: Nibbs gravelly silt loam--range. On a 5 percent, single
slope, east aspect, 5000 feet elevation. (The profile was moist below
4 inches when described on June 29, 1982. Colors are for air-dry soil
unless otherwise stated.)
A1--0 to 2 inches; pale brown (10YR 6/3) gravelly silt loam, very
dark grayish brown (10YR 3/3) moist; weak very fine granular structure;
soft, very friable and slightly plastic; 30 percent pebbles; mildly
alkaline (pH 7.8); abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 7 inches; pale brown (10YR 6/3) silt loam, very dark
grayish brown (10YR 3/3) moist; weak very thick platy structure parting
to moderate fine subangular blocky; slightly hard, very friable,
slightly sticky, and plastic; many very fine and few fine roots; many
very fine tubular pores; 10 percent pebbles; mildly alkaline (pH 7.8);
abrupt smooth boundary. (2 to 7 inches thick)
Bw1--7 to 12 inches; very pale brown (10YR 7/3) gravelly silt loam,
dark brown (10YR 4/3) moist; moderate medium and fine subangular blocky
structure; hard, very friable, slightly sticky, and plastic; few very
fine and fine roots; many very fine tubular pores; 5 percent cobbles,
10 percent pebbles; mildly alkaline (pH 7.8); abrupt wavy boundary. (2
to 5 inches thick)
Bw2--12 to 18 inches; very pale brown (10YR 7/3) gravelly silt
loam, dark brown (10YR 4/3) moist; weak medium and coarse subangular
blocky structure; slightly hard, very friable, slightly sticky, and
plastic; few very fine roots; many very fine and few fine tubular
pores; slightly effervescent; 20 percent pebbles; moderately alkaline
(pH 8.4); clear wavy boundary. (5 to 13 inches thick)
2Bk1--18 to 31 inches; very pale brown (10YR 8/3) very gravelly
loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky
structure; hard, very friable, sticky and plastic; few very fine roots;
many very fine and few fine tubular pores; strongly effervescent; many
violently effervescent fine and medium irregularly shaped soft lime
seams and masses; 5 percent cobbles, 45 percent pebbles; rock fragments
coated with lime on all sides; strongly alkaline (pH 9.0); clear wavy
boundary. (8 to 19 inches thick)
2Bk2--31 to 41 inches; very pale brown (10YR 8/3) extremely
gravelly sandy loam, brown (10YR 5/3) moist; massive; hard and very
friable; few very fine roots; many very fine and few fine tubular
pores; 10 percent cobbles, 60 percent pebbles; rock fragments coated
with lime on all sides; strongly effervescent; common violently
effervescent fine and medium irregularly shaped, soft, lime seams and
masses; strongly alkaline (pH 9.0); clear wavy boundary. (8 to 15
inches thick)
3C--41 to 60 inches; multicolored stratified extremely gravelly
loamy coarse sand; single-grained; loose; few very fine roots; many
very fine irregular pores; 5 percent stones, 15 percent cobbles, 60
percent pebbles; rock fragments coated with lime on undersides;
strongly alkaline (pH 8.6).
TYPE LOCATION: Cassia County, Idaho; about 6 miles southwest of Malta,
Idaho; about 1650 feet west and 100 feet north of the southeast corner
of sec. 4, T. 14 S., R. 26 E.
RANGE IN CHARACTERISTICS:
Depth to first discontinuity - 10 to 21 inches
Depth to stratified sand and gravel - 21 to 41 inches
Depth to secondary lime - 10 to 15 inches
Average annual soil temperature - 47 to 49 degrees F.
Rock fragments in control section - 40 to 75 percent
A horizons
Value- 5 or 6 dry, 3 or 4 moist
Chroma- 2 or 3
Reaction - mildly or moderately alkaline
Bw horizons
Value- 6 or 7 dry, 3 or 4 moist
Texture - GR-SIL, GR-L, or L
Clay content - 15 to 25 percent
Reaction - mildly through strongly alkaline
2Bk horizons
Value- 7 or 8 dry, 4 through 7 moist
Chroma- 3 or 4
Texture - GRV-L, GRV-SL, or GRX-SL
Rock fragment content - 40 to 75 percent
Reaction - moderately or strongly alkaline
3C horizon
Texture - stratified, GRV-SL through GRX-COS
Rock fragment content - 45 to 75 percent
Reaction - moderately or strongly alkaline
COMPETING SERIES: These are the Bluegulch (T), Finley, Kiona, Mackey,
Minat, Veet and Veta series. Bluegulch soils are deep to a lithic
contact, are over 18 inches to secondary lime, and have average annual
soil temperature greater than 51 degrees F. Finley and Kiona soils
have an average annual soil temperature greater than 50 degrees F.
Mackey soils are moderately deep to a lithic contact. Minat soils have
15 to 27 percent clay throughout the profile and lack very coarse
textures in the lower part of the profile. Veet soils are moderately
coarse to coarse textured in the upper 24 inches. Veta soils lack
secondary lime above 15 inches and lack a discontinuity within the
control section.
GEOGRAPHIC SETTING: Nibbs soils are on coalesced fan terraces. Slopes
range from 2 to 8 percent. Elevation ranges from 4800 to 5500 feet.
The soils formed in mixed alluvium with some loess influence. The
average annual precipitation is about 8 to 12 inches and the average
annual air temperature is about 45 to 47 degrees F. The frost free
season is 95 to 115 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Darkbull, Gunnell (T),
Kancan (T), and Womack (T) series. Darkbull soils are calcareous to
the surface and lack a cambic horizon. Gunnell soils have a duripan at
10 to 20 inches. Kancan soils have a mollic epipedon. Womack soils
have an argillic horizon and a duripan at 20 to 40 inches. These soils
occur on coalesced fan terraces.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately
permeable in the upper part and rapid to very rapid below.
USE AND VEGETATION: Nibbs soils are used for range and wildlife
habitat. The potential natural vegetation is low sagebrush, bluebunch
wheatgrass, Sandberg bluegrass and bottlebrush squirriltail.
DISTRIBUTION AND EXTENT: The soils of this series are inextensive in
southern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Cassia County, Idaho, 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon
are:
Ochric epipedon - the zone from the surface to 7 inches (A1 and A2
horizons)
Cambic horizon - the zone from 7 to 18 inches (Bw1 and Bw2 horizons)
Control section - 10 to 40 inches
Secondary lime accumulation - the zone from 18 to 41 inches (2Bk1 and
2Bk2 horizons)
National Cooperative Soil Survey