LOCATION BOUNDARY WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Andic Haploxeralfs
TYPICAL PEDON: Boundary ashy silt loam - on a northwest facing planar slope of 30 percent under a coniferous forest at 3,700 feet elevation. (Colors are for dry soil unless otherwise stated.)
Oe--0 to 1 inch; partially decomposed needles, leaves, twigs, bark, cones, and seeds; abrupt smooth boundary. (0 to 1 1/2 inches thick)
E--1 to 1.5 inches; gray (10YR 6/1) ashy very fine sandy loam, dark gray (10YR 4/1) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common fine and medium roots; 5 percent pebbles; moderately acid (pH 5.8); abrupt broken boundary. (0 to 1 inch thick)
Bw--1.5 to 11 inches; yellowish brown (10YR 5/4) ashy silt loam, dark brown (7.5YR 3/4) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; moderately smeary; common very fine and fine, few medium and coarse roots; 10 percent pebbles; moderately acid (pH 6.0); clear wavy boundary. (8 to 13 inches thick)
2Bt1--11 to 16 inches; light yellowish brown (2.5Y 6/4) very gravelly silt loam; olive brown (2.5Y 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few very fine, fine, and coarse roots; few moderately thick clay films on ped faces and lining pores; 30 percent pebbles, 5 percent cobbles; moderately acid (pH 5.8); clear wavy boundary. (4 to 7 inches thick)
2Bt2--16 to 22 inches; pale olive (5Y 6/4) very gravelly silty clay loam, olive (5Y 4/3) moist; moderate medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; many prominent clay films on ped faces and lining pores; 30 percent pebbles and 10 percent cobbles; neutral (pH 7.0); clear wavy boundary. (5 to 8 inches thick)
2Bt3--22 to 26 inches; olive (5Y 5/3) very gravelly silt loam, olive (5Y 4/3) moist; moderate fine and medium subangular blocky; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; common distinct clay films on ped faces and common prominent lining pores; 30 percent pebbles and 10 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (3 to 6 inches thick)
2Bk--26 to 41 inches; pale olive (5Y 6/3) very gravelly silt loam, olive (5Y 4/3) moist; moderate medium and thick platy structure; hard, firm, slightly sticky and moderately plastic; 30 percent pebbles and 15 percent cobbles; lime segregated in common, rounded, fine, soft masses and as pendants below pebbles and cobbles; strongly effervescent; slightly alkaline (pH 7.4); clear wavy boundary. (12 to 17 inches thick)
2C--41 to 60 inches; light olive gray (5Y 6/2) very gravelly silty clay loam, olive gray (5Y 5/2) moist; moderate medium and thick platy structure; hard, firm, very sticky and moderately plastic; 35 percent pebbles and 10 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Pend Oreille County, Washington; 3.5 miles southwest of Boundary Dam; 660 feet north and 660 feet east of the southwest corner, sec. 17, T. 40 N., R. 44 E., WM.
RANGE IN CHARACTERISTICS: The depth to free carbonates is 23 to 35 inches, commonly 23 to 30 inches. This soil is usually moist, but is dry on all parts between 8 and 24 inches for 60 to 75 consecutive days following the summer solstice. The mean annual soil temperature at 20 inches ranges from 45 to 47 degrees F. The volcanic ash mantle is 7 to 14 inches thick. The argillic horizon is silt loam, clay loam, or silty clay loam, and averages 20 to 35 percent clay. The control section has 35 to 50 percent coarse fragments.
The E horizon, when present, has value of 6 or 7 dry, 4 or 5 moist, and chroma of 1 or 2 dry or moist.
The Bw horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry or moist. It is moderately acid or slightly acid. It is modified by 0 to 10 percent coarse fragments.
The 2Bt horizon has hue of 2.5Y or 5Y, value of 5 to 7 dry, and chroma of 3 to 4 moist and 2 through 4 dry. It is heavy silt loam, clay loam, or silty clay loam, and is modified by 30 to 40 percent pebbles and 5 to 10 percent cobbles. Reaction is moderately acid to slightly alkaline.
The 2Bk horizon is heavy silt loam, silty clay loam, or clay loam and is modified by 25 to 35 percent pebbles and 10 to 15 percent cobbles. It is slightly alkaline or moderately alkaline and is strongly or violently effervescent.
The 2C horizon has value of 4 or 5 moist and chroma of 2 or 3 dry and moist. It is clay loam or silty clay loam, and is modified by 35 to 45 percent pebbles and 5 to 10 percent cobbles. It is slightly or strongly effervescent.
COMPETING SERIES: These are the Gosch and Weste series. Gosch soils are deep to a paralithic contact. Weste soils are moderately deep to a lithic contact.
GEOGRAPHIC SETTING: Boundary soils are on glaciated foothill slopes and ridgetops at elevations of 3,000 to 4,500 feet. They are formed in fine-textured calcareous glacial till with a mantle of volcanic ash. Slopes range from 0 to 65 percent and have planar and complex surfaces. The mean annual temperature ranges from 43 to 45 degrees F., and the average annual precipitation is 30 to 40 inches. The frost-free season is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahren, Belzar, and Threemile soils. Ahren soils are in the fine loamy family. Belzar soils are 20 to 40 inches deep and formed from limestone bedrock. All three soils lack an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderate permeability in the upper 10 inches and moderately slow in the underlying glacial till.
USE AND VEGETATION: Used for woodland, wildlife habitat, watershed, and recreation. Native vegetation includes western hemlock, western redcedar, grand fir, Douglas-fir, western white pine, mountain alder, mock orange, oceanspray, Oregon-grape, pathfinder, evergreen violet, pachystima, mallow ninebark, common snowberry, strawberry, twistedstalk, wild rose, thimbleberry, and dwarf huckleberry.
DISTRIBUTION AND EXTENT: Northeastern Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Pend Oreille County Area, Washington, l981.
REMARKS: Diagnostic horizons and features recognized in this pedon are a mantle of volcanic ash and loess from 1 to 11 inches with an estimated moist bulk density of less than 1.0 g/cc and acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of more than 1.0 percent. A ochric epipedon from the surface to 11 inches, an argillic horizon from 11 to 26 inches, and a calcic horizon from 26 to 41 inches. The particle-size control section is the entire argillic horizon from 11 to 26 inches (2Bt1, 2Bt2, and 2Bt3 horizons).
ADDITIONAL DATA: CaCO3 equivalent field procedure determined the 2Bk (26 to 41 inches) to be 53 percent and the 2C at 36 percent (41 to 60 inches). The 2Bk horizon is a calcic horizon and is presumed to be a function of secondary carbonate enrichment in calcareous glacial till. Whereas, the carbonate value in the 2C horizon is presumed to reflect the inherent carbonate value of the glacial till.