LOCATION GRANDAD ID

Established Series
Rev: BDC/BDG/RJS
11/2015

GRANDAD SERIES

The Grandad series consists of very deep well drained soils that formed in material derived from mica schist and gneiss with a thick mantle of volcanic ash. They are on mountain slopes and ridgetops. Slopes range from 5 to 75 percent. The average annual precipitation is about 1,150 mm and the average annual temperature is about 5.6 degrees C.

TAXONOMIC CLASS: Ashy over loamy, amorphic over micaceous, frigid Alfic Udivitrands

TYPICAL PEDON: Grandad ashy silt loam, forested, on a 56 percent slope at 1,140 meters elevation. Aspect is northwest. (Colors are for dry soil unless otherwise indicated)

Oi--0 to 3 cm; partially decomposed needles, leaves, twigs and moss.

A--3 to 8 cm; yellowish brown (10YR 5/4) ashy silt loam, very dark brown (7.5YR 2.5/2) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots throughout; many very fine and fine irregular pores; 2 percent fine mica flakes; slightly acid (pH 6.3); abrupt smooth boundary. (5 to 23 cm thick)

Bw1--8 to 25 cm; yellowish brown (10YR 5/4) ashy silt loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure parting to weak fine and very fine granular; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium roots throughout; many very fine and fine irregular and few very fine and fine tubular pores; 2 percent fine mica flakes; 1 percent schist gravel; slightly acid (6.5); clear smooth boundary.

Bw2--25 to 48 cm; brownish yellow (10YR 6/6) ashy silt loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots throughout; many very fine irregular and few very fine and fine tubular pores; 2 percent fine mica flakes; 1 percent schist gravel; slightly acid (pH 6.4); abrupt wavy boundary. (Combined thickness of Bw horizons is 13 to 58 cm)

2Bt1--48 to 56 cm; light yellowish brown (10YR 6/4) loam, dark brown (7.5YR 3/4) moist; moderate fine and medium subangular blocky structure; moderately hard, friable, slightly sticky and moderately plastic; many very fine and fine roots between peds and few medium roots throughout; common very fine irregular and tubular pores; few (2 percent) faint clay films in pores; many (40 percent), faint silt coats in pores and on faces of peds; 15 percent fine mica flakes; 3 percent schist gravel; slightly acid (pH 6.1); clear wavy boundary.

2Bt2--56 to 76 cm; very pale brown (10YR 7/4) gravelly loam, dark yellowish brown (10YR 3/6) moist; moderate fine and medium subangular blocky structure; moderately hard, friable, slightly sticky and moderately plastic; common very fine and fine roots between peds and few medium roots throughout; common very fine irregular and common very fine tubular pores; common (5 percent) distinct clay films in pores and common (10 percent) faint clay films in pores; many (30 percent) faint silt coats on faces of peds; 35 percent fine mica flakes; 15 percent schist gravel and 5 percent schist cobbles; slightly acid (pH 6.1); clear wavy boundary.

2Bt3--76 to 99 cm; very pale brown (10YR 7/4) gravelly loam, yellowish brown (10YR 5/4) moist; moderate fine and medium subangular blocky structure; moderately hard, friable, nonsticky and moderately plastic; common very fine and fine roots between peds; common very fine irregular and few very fine tubular pores; common (15 percent) distinct clay films in pores and common (5%) faint clay films on faces of peds; 35 percent fine mica flakes; 20 percent schist gravel and 10 percent schist cobbles; moderately acid (pH 5.8); clear wavy boundary.

2Bt4--99 to 114 cm; very pale brown (10YR 7/4) gravelly loam, strong brown (7.5YR 4/6) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots between peds; common very fine irregular and few very fine tubular pores; common (5 percent) distinct clay films in pores and common (8%) faint clay films on faces of peds; 30 percent fine mica flakes; 15 percent schist gravel; moderately acid (pH 5.8); clear wavy boundary. (Combined thickness of Bt horizons is 35 to 125 cm)

2C1--114 to 147 cm; brownish yellow (10YR 6/6) loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine, fine and medium roots throughout; common very fine irregular pores; 45 percent fine mica flakes; 10 percent schist gravel; strongly acid (pH 5.5) clear wavy boundary.

2C2--147 to 163 cm; dark yellowish brown (10YR 4/6) paragravelly sandy loam, dark brown (7.5YR 3/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots throughout; common very fine irregular pores; 55 percent fine mica flakes; 15 percent schist paragravel; strongly acid (pH 5.2).

TYPE LOCATION: Latah County, Idaho; about 8 kilometers south of Bovill, Idaho; about 180 meters north and 792 meters west of the southeast corner of Sec. 30, T40N, R1E; Latitude - 46 degrees, 46 minutes, 36 seconds North; Longitude - 116 degrees, 22 minutes, 58 seconds West; UTM Zone 11N, Easting 547119.8, Northing 5180531.3; USGS Bovill Quadrangle.

RANGE IN CHARACTERISTICS:

Average annual soil temperature - 3.9 to 7.2 degrees C.
Soil moisture control section - not dry for 45 consecutive days from June to October. Udic moisture regime.
Mica content of mineralogy control section - 30 to 85 percent by volume

Thickness of volcanic ash - 36 to 64 cm
Volcanic glass - 15 to 50 percent
AO extractable Al+1/2Fe - 1.3 to 2.7 percent
Phosphorous retention - 55 to 95 percent
15 bar water retention - 8.0 to 12.0 percent on air dried samples

A horizon
Hue - 7.5YR or 10YR
Value - 3 to 5 dry, 2.5 to 4 moist
Chroma - 2 to 4 dry, 1 to 4 moist
Texture - ashy silt loam or ashy loam
Clay content - 7 to 12 percent
Rock fragments - 0 to 3 percent gravel
Reaction - 5.3 to 6.6
Bulk density - 0.60 to 0.90 g/cc

Bw1, Bw2 horizons
Hue - 7.5YR or 10YR
Value - 5 or 6 dry, 3 to 6 moist
Chroma - 3 or 4 moist, 4 or 6 dry
Texture - ashy silt loam or ashy loam
Clay content - 7 to 12 percent
Rock fragments - 0 to 3 percent gravel
Reaction - 5.5 to 6.8
Bulk density - 0.60 to 1.00 g/cc

2Bt1, 2Bt2, 2Bt3 horizons
Hue - 7.5YR or 10YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 to 6 dry, 3 to 8 moist
Textures - silt loam, loam, very fine sandy loam, fine sandy loam or sandy loam
Clay content - 11 to 23 percent
Rock fragments - 0 to 20 percent gravel, 0 to 10 percent cobbles, 0 to 15 percent stones, 0 to 40 percent total rock fragment content
Reaction - 4.9 to 6.5

2Bt4 horizon
Hue - 7.5YR to 2.5Y
Value - 6 or 7 dry, 3 to 6 moist
Chroma - 3 to 6 dry, 3 to 8 moist
Textures - loam, fine sandy loam, sandy loam or loamy sand
Clay content - 13 to 23 percent
Rock fragments - 0 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 40 percent stones, 0 to 55 percent total rock fragment content
Reaction - 4.9 to 6.5

2C1, 2C2 horizons
Hue - 7.5YR to 2.5Y
Value - 4 to 8 dry, 3 to 7 moist
Chroma - 3 to 6 dry, 4 to 8 moist
Texture - loam, fine sandy loam, sandy loam, loamy fine sand or loamy sand
Clay content - 3 to 19 percent
Rock fragments - 0 to 50 percent gravel, 0 to 20 percent cobbles, 0 to 40 percent stones, 0 to 55 percent total rock fragment content
Pararock fragments - 0 to 15 percent paragravel
Reaction - 4.8 to 6.4

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Landform - mountain slopes and ridgetops
Elevation - 475 to 1,550 meters
Slopes - 5 to 75 percent
Parent material - material derived from mica schist and gneiss with a thick mantle of volcanic ash
Mean annual precipitation - 750 to 1,525 mm.
Mean annual temperature - 3.3 to 7.8 degrees C.
Frost-free period - 50 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Rettig, Nakarna, Bouldercreek and Township series. Rettig soils are on mountain slopes and ridgetops and lack an argillic horizon. Nakarna soils are on mountain slopes and are deep to a paralithic contact. Bouldercreek soils are on mountain slopes and canyons and have more than 35 percent rock fragments. Township soils are on mountain slopes and are loamy-skeletal.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, moderately high saturated hydraulic conductivity.

USE AND VEGETATION: These soils are used for timber production, wildlife habitat, watershed and recreation. Potential natural vegetation is western redcedar, grand fir, Douglas-fir, western white pine and western larch with an understory of wild ginger, queencup beadlilly, goldthread, starry false Solomon's seal, Hooker fairybells and northern twinflower.

DISTRIBUTION AND EXTENT: North-Central Idaho; Grandad soils are moderately extensive. MLRA 43A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Clearwater County, Idaho 2003.

REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Ochric epipedon - from 0 to 8 cm (Oi, A horizons);
Cambic horizon - from 8 to 48 cm (Bw1, Bw2 horizons);
Argillic horizon - The zone from 48 to 114 cm (2Bt1, 2Bt2, 2Bt3, 2Bt4 horizons);
Volcanic ash cap - from 3 to 48 cm (A, Bw1 and Bw2 horizons); and
Particle size control section - from 3 to 103 cm. (A, Bw1, Bw2, 2Bt1, 2Bt2, 2Bt3, part of 2Bt4 horizons).

Comments: The values listed in the Range in Characteristics for bulk density, volcanic glass, AO extractable Al+1/2Fe, phosphorous retention and 15 bar water retention are estimates only.

ADDITIONAL DATA: Laboratory data exists for this series. Soil Survey Sample No. S95ID-035-010 (project no. 96P 5, pedon no. 96P 27) Clearwater County, Idaho; by NSSL, Lincoln NE

Additional Information: The mineralogy class was changed from paramicaceous to micaceous in 07/2010 by the National Soil Survey Center on request of the responsible MLRA regional office. The change was necessary based on the eleventh edition of the Keys to Soil Taxonomy, 2010.

National Cooperative Soil Survey
U.S.A.