LOCATION PIONEERVIL IDEstablished Series
The Pioneervil series consists of very deep, moderately well drained soils with moderately rapid permeability that formed in alluvium from igneous rocks. Slopes range from 0 to 3 percent in intermontane basins, mountain valleys and canyons. The mean annual precipitation is about 24 inches and the mean annual temperature is about 43 degrees F.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Fluventic Haploxerolls
TYPICAL PEDON: Pioneervil sandy loam -- on a nearly level flood-plain step at 4,320 feet elevation in grazed woodland. When described on May 2, 2002, the soil was moist to 50 inches and wet below. (Colors are for air-dry soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed pine needles and other plant materials.
A1--1 to 6 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine, few medium and coarse roots; many very fine and fine, few medium irregular pores; 10 percent fine gravel; neutral (pH 6.8); clear smooth boundary.
A2--6 to 12 inches; brown (10YR 5/3) fine gravelly sandy loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine and fine, few medium and coarse roots; common very fine and fine, few medium tubular pores; 15 percent fine gravel; neutral (pH 6.6); abrupt smooth boundary. (combined A horizon - 10 to 20 inches thick)
Bw1--12 to 19 inches; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine, few medium and coarse roots; common very fine and fine, few medium tubular and irregular pores; 5 percent fine gravel; moderately acid (pH 6.0); clear smooth boundary.
Bw2--19 to 25 inches; pale brown (10YR 6/3) fine gravelly sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine, few medium roots; common very fine and fine, few medium irregular pores; 20 percent fine gravel; slightly acid (pH 6.3); abrupt wavy boundary. (combined Bw horizon - 6 to 24 inches thick)
BC--25 to 31 inches; light yellowish brown (2.5Y 6/3) very fine sandy loam, olive brown (2.5Y 4/3) moist; weak medium platy structure parting to moderate fine and medium subangular blocky; slightly hard, friable, moderately sticky and slightly plastic; few very fine, fine and medium roots; common very fine and fine, few medium tubular pores; 5 percent fine gravel; slightly acid (pH 6.1); abrupt smooth boundary. (0 to 6 inches thick)
Ab--31 to 35 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable; nonsticky and nonplastic; few very fine, fine and medium roots; common very fine and fine tubular pores; few fine faint (10YR 4/3 moist) Fe masses with diffuse boundaries; 5 percent gravel; slightly acid (pH 6.1); abrupt smooth boundary. (0 to 12 inches thick)
C1--35 to 41 inches; light yellowish brown (10YR 6/4) sand, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky and nonplastic; few very fine, fine and medium roots; many very fine and fine, few medium irregular pores; highly oxidized matrix; 5 percent fine gravel; neutral (pH 6.7); abrupt wavy boundary. (0 to 10 inches thick)
C2--41 to 52 inches; very pale brown (10YR 7/3) gravelly sandy loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine and fine tubular and irregular pores; few discontinuous lamellae 2 to 5 mm thick; common fine and medium distinct (10YR4/6 moist) Fe masses; 15 percent gravel; neutral (pH 6.7); clear smooth boundary.
C3--52 to 60 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few very fine and fine tubular pores; common fine faint (10YR 4/4 moist) Fe masses, common fine and medium faint (10YR 5/2 moist) depletions; common organic stains; few discontinuous lamellae 2 to 5 mm thick; neutral (pH 6.9); clear smooth boundary.
C4--60 to 72 inches; pale brown (10YR 6/3) loamy sand, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine irregular pores; common fine and medium distinct (10YR 4/6 moist) Fe masses, common fine and medium faint (10YR 5/2 moist) depletions; 5 percent fine gravel; neutral (pH 7.0); abrupt smooth boundary.
C5--72 to 75 inches; variegated fine gravelly coarse sand; single grain; loose, nonsticky and nonplastic; many very fine and fine, few medium irregular pores; 20 percent fine gravel; neutral (pH 7.2).
TYPE LOCATION: Boise County, Idaho; about 3 miles southwest of Placerville; 550 feet north and 1,050 feet east of the southwest corner of section 28, T.7 N., R.4 E.; USGS Placerville Quadrangle; Latitude - 43 degrees, 54 minutes, 37 seconds N. and Longitude - 115 degrees, 58 minutes, 34 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon - 10 to 20 inches
Thickness of solum - 30 to 45 inches
Depth to diagnostic redoximorphic features - 40 to 60 inches (relict redoximorphic features occur above 40 inches in some pedons)
Depth to bedrock - 60 inches or more
Particle-size control section (wt. avg.) - 5 to 18 percent clay; 50 to 70 percent fine sand and coarser; 0 to 25 percent rock fragments
Moisture control section - dry 45 to 75 consecutive days following the summer solstice
Mean annual soil temperature - 44 to 47 degrees F.
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Clay content - 10 to 18 percent
Rock fragments - 0 to 25 percent gravel
Reaction - slightly acid or neutral
Bw horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - FSL, SL or L
Clay content - 10 to 20 percent
Rock fragments - 0 to 25 percent gravel
Reaction - moderately acid or slightly acid
Ab horizon (when present)
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 or 3 dry or moist
Texture - COSL, SL or LFS
Clay content - 6 to 18 percent
Rock fragments - 0 to 15 percent gravel
C horizon
Hue - 7.5YR or 10YR
Value - 5 through 7 dry, 3 through 5 moist
Chroma - 2 through 4 dry or moist
Texture (stratified) - FSL, SL, LFS, LS, LCOS, S or COS
Clay content - 0 to 12 percent
Rock fragments - 0 to 35 percent gravel, 0 to 10 percent cobbles and 0 to 35 percent total
Reaction - moderately acid through neutral
Redoximorphic features (below 40 inches) - common or many, faint through prominent Fe masses; none through common, faint or distinct depletions
Thin discontinuous lenses of sandy and/or loamy material with variable organic matter content are common
COMPETING SERIES: There are no competing series. Lostcreek soils are similar, but have a vitrandic surface. Monache soils are similar, but have cumulic epipedons.
GEOGRAPHIC SETTING: Pioneervil soils are on flood plains at elevations of 3,400 to 4,650 feet. Slopes range from 0 to 3 percent. These soils formed in stratified loamy and sandy alluvium from igneous rocks (dominantly granodiorite). The mean annual precipitation is 22 to 28 inches. The mean annual temperature is 42 to 45 degrees F. The frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brassey, Grimescreek and Middlefork soils. Brassey soils are well drained, loamy-skeletal and occur on fan remnants. Grimescreek soils are somewhat poorly drained, have cumulic epipedons and occur on lower flood-plain steps. Middlefork soils are well drained, have fine-loamy argillic horizons and occur on hill slopes and fan remnants.
DRAINAGE AND PERMEABILITY: Moderately well drained with a high water table at 40 to 60 inches below the surface at some time during April through June; very slow runoff; moderately rapid permeability. Pioneervil soils are subject to rare flooding for very brief to brief periods in December through June.
USE AND VEGETATION: Pioneervil soils are used mainly for pastureland. Native vegetation is ponderosa pine and common snowberry.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 44. Pioneervil soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Boise County Area, Idaho, Parts of Ada and Boise Counties, 2005.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone from 1 to 12 inches (A1 and A2 horizons)
Cambic horizon - zone 12 to 25 inches (Bw1 and Bw2 horizons)
Buried horizon - zone 31 to 35 inches (Ab horizon)
Redoximorphic features (current conditions) - zone from 41 to 75 inches (C2, C3, C4 and C5 horizons)
Particle-size control section - zone from 11 to 41 inches (A contrasting family of loamy over sandy or sandy-skeletal is not met based on more than 50 percent fine sand and coarser in the upper part of the control section.)
Soil moisture regime xeric
All depths related to diagnostic horizons and features listed in the range in characteristics are from the top of the first mineral horizon.