LOCATION BROADAX            WA+ID
Established Series
Rev. DDS/SHB/SBC
09/2009

BROADAX SERIES


The Broadax series consists of very deep and deep, well drained soils formed in loess on hills. Slopes are 0 to 40 percent. The mean annual precipitation is about 16 inches and the mean annual temperature is about 49 degrees F.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Calcic Argixerolls

TYPICAL PEDON: Broadax silt loam - cultivated. (Colors are for dry soil unless otherwise stated.)

Apl--0 to 4 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak very fine granular structure; soft, very friable, slightly sticky and slightly plastic; few roots; many very fine pores; slightly acid (pH 6.2); clear smooth boundary.

Ap2--4 to 8 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; soft, very friable, moderately sticky and slightly plastic; few roots; many fine pores; slightly acid (pH 6.2); clear smooth boundary. (Combined thickness of the Ap horizon is 3 to 11 inches thick)

A--8 to 16 inches; yellowish brown (10YR 5/4) silt loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few roots; few very fine pores; neutral (pH 6.8); gradual smooth boundary. (6 to 9 inches thick)

Bt--16 to 31 inches; yellowish brown (10YR 5/4) heavy silt loam, dark yellowish brown (10YR 3/4) moist; moderate coarse prismatic structure parting to moderate fine subangular blocky; hard, firm, moderately sticky and moderately plastic; few roots; few very fine pores; faint patchy clay films on faces of peds; slightly alkaline (pH 7.4); clear wavy boundary. (8 to 24 inches thick)

Btk--31 to 35 inches; yellowish brown (10YR 5/4) silt loam, brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate fine subangular blocky; hard, firm, moderately sticky and slightly plastic; few roots; few fine pores; faint patchy clay films on faces of peds; strongly effervescent; thin carbonate accumulations along faces of peds; moderately alkaline (pH 8.2); clear wavy boundary. (2 to 5 inches thick)

Bk1--35 to 44 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few roots; many fine pores; soft powdery carbonate accumulations along cracks and seams; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (7 to 12 inches thick)

Bk2--44 to 60 inches; brown (10YR 5/3) silt loam, brown (10YR 4/3) moist; massive, soft, very friable, slightly sticky, nonplastic; few roots; many fine and common very fine pores; soft powdery carbonate accumulations along cracks and in seams; violently effervescent; strongly alkaline (pH 8.6).

TYPE LOCATION: Lincoln County, Washington; 1,600 feet west and 2,220 feet south of the northeast corner of section 18, T. 24 N., R. 38 E.

RANGE IN CHARACTERISTICS:
Average annual soil temperature - 47 to 53 degrees F
Moisture control section - dry in all parts between depths of 4 and 12 inches for 75 to 105 days after the summer solstice, July to September, moist October through June
Thickness of mollic epipedon - 10 to 20 inches
Depth to base of argillic horizon - greater than 30 inches
Depth to secondary carbonates - 25 to 44 inches
Calcium carbonate content - less than 15 percent throughout
Clay content in particle-size control section - 18 to 35 percent and less than 15 percent fine sand and coarser
Durinodes - present in some pedons below 40 inches (in Spokane County)

Ap horizon and A horizon
Hue - 10YR or 2.5Y
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 to 3 moist, 2 to 4 dry
Structure - moderate or weak granular, platy or subangular blocky
Reaction - moderately acid to slightly alkaline

AB horizon present in some pedons

Bt and Btk horizons (when present)
Value - 4 to 7 dry, 2 to 4 moist
Chroma - 2 to 4 moist or dry
Texture - silt loam or silty clay loam
Structure - moderate or strong subangular blocky or prismatic
Secondary calcium carbonates (when present) - visible when moist in pores, root channels or within matrix
Clay films - faint to distinct, continuous, on vertical faces of peds
Reaction - neutral to strongly alkaline

Bk horizon
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 2 to 4 moist or dry
Texture - silt loam, loam, silty clay loam or sandy loam
Sand fraction - 0 to 10 percent, medium, quartz feldspar
Rock fragments - 0 to 10 percent
Reaction - slightly alkaline to strongly alkaline

Bkq, Bq, Btkb horizons present in some pedons

COMPETING SERIES: These are the McKay, Morrow, Nephi, Parleys, and Wannacott, series.
McKay soils - lithologic discontinuity within 40 inches with 20 to 50 percent rock fragments of alluvial origin; E horizon present
Morrow soils - 20 to 40 inches to lithic contact (basalt)
Nephi soils - hue of 7.5YR or 5YR in Bt horizon; particle-size control section calcareous throughout
Parleys soils - calcic horizon with 15 to 40 percent calcium carbonate equivalent; 30 to greater than 60 inches to redox concentrations (well and moderately well drained)
Wannacot soils - 20 to 40 inches to densic contact (glacial till material)

GEOGRAPHIC SETTING: Broadax soils are on hillslopes and plateaus at elevations of 800 to 3,500 feet. Slopes are 0 to 40 percent. The soils formed in old loess mixed with recent loess in the upper part. Summers are hot and dry and winters are cool and moist. The mean annual precipitation is dominantly 15 to 18 inches: the low precipitation phase ranges to 12 to 16 inches; some areas in eastern Washington and Idaho range to 20 inches. The average July temperature is 69 degrees F. and the average January temperature is 27 degrees F. The mean annual temperature is 46 to 50 degrees F. The frost-free season is 105 to 170 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anders, Bagdad, Benge, Calouse, Dragoon, and Reardan soils. Anders soils lack an argillic horizon and are moderately deep to basalt bedrock (lithic contact). Benge soils lack an argillic horizon and are sandy-skeletal in the lower part of the particle-size control section. Bagdad soils are coarse-silty. Calouse soils lack an argillic horizon and have a mollic epipedon more than 20 inches thick. Dragoon soils are underlain by a paralithic contact with granite at a depth of 20 to 40 inches. Reardan soils are in a fine family.

DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate or moderately slow permeability.

USE AND VEGETATION: These soils are used mostly for cropland but other minor uses include livestock grazing and timber production. Dryland small grains are common crops. Native vegetation is Idaho fescue, bluebunch wheatgrass, balsamroot, and scattered big sagebrush on the low precipitation phase and ponderosa pine with an understory of Idaho fescue, bluebunch wheatgrass, common snowberry and rose on the high precipitation phase.

DISTRIBUTION AND EXTENT: Eastern Washington and northern Idaho. MLRA 8. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Lincoln County, Washington, 1978.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon the zone from 0 to 16 inches
Argillic horizon the zone from 16 to 35 inches
Calcium carbonate accumulation the zone from 31 to 60 inches
Particle-size control section the zone from 16 to 35 inches

ADDITIONAL DATA: National Soil Survey Lab user pedon IDs and lab pedon IDs - 82ID069003 (83P0189), 82ID069008 (83P0194), 85ID069002 (85P0980), 87WA017007 (87P0505), 90WA017011 (90P1019), 92WA017001 (93P0367)


National Cooperative Soil Survey
U.S.A.