LOCATION CALDWELL WA+IDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Cumulic Haploxerolls
TYPICAL PEDON: Caldwell silt loam, cultivated. (Colors are for dry soils unless otherwise stated.)
Ap--0 to 9 inches, grayish brown (10YR 5/2) silt loam, very dark gray (10YR 3/1) moist; weak coarse platy structure parting to weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; many roots, common fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (6 to 10 inches thick)
A--9 to 17 inches, dark gray (10YR 4/1) silt loam, black (10YR 2/1) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, moderately sticky and slightly plastic; common roots; common fine tubular pores; common organic staining; neutral (pH 7.2); clear smooth boundary. (7 to 9 inches thick)
ABt--17 to 26 inches, dark gray (10YR 4/1) heavy silt loam, very dark gray (10YR 3/1) moist; moderate medium prismatic structure parting to moderate medium angular blocky; hard, slightly firm, moderately sticky and moderately plastic; common roots; many fine tubular pores; few faint patchy clay films on faces of peds; few distinct organic stains on faces of peds; few faint silica coatings on vertical faces peds; neutral (pH 7.2); clear smooth boundary. (7 to 10 inches thick)
Bt--26 to 39 inches, gray (10YR 5/1) silty clay loam, very dark gray (10YR 3/1) moist; moderate medium prismatic parting to moderate medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; common roots; common fine tubular pores; few faint patchy clay films on faces of peds; few distinct silica coatings on faces of peds; neutral (pH 7.2); abrupt smooth boundary (10 to 15 inches thick)
Btg--39 to 54 inches, light brownish gray (2.5Y 6/2) silty clay loam, very dark grayish brown (2.5Y 3/2) moist; massive; hard, firm, moderately sticky and moderately plastic; few roots; few fine tubular pores; few faint clay films on faces of peds; many fine prominent yellowish brown (10YR 5/6) moist, masses of iron accumulation with clear boundaries, and few fine prominent brown (7.5YR 4/4) moist, masses of iron accumulation with sharp boundaries in the matrix; neutral (pH 7.2); abrupt smooth boundary. (14 to 20 inches thick)
BCg--54 to 61 inches, light brownish gray (2.5Y 6/2) light silty clay loam, dark grayish brown (2.5Y 4/2) moist; massive; hard, firm, moderately sticky and moderately plastic; no roots; few fine tubular pores; common fine masses of iron accumulation throughout; neutral (pH 7.0).
TYPE LOCATION: Whitman County, Washington - 400 feet west and 200 feet north of the southeast corner of section 15, T. 15 N., R. 45 E. Latitude 46 degrees, 46 minutes, 45.15 seconds North; Longitude 117 degrees, 7 minutes, 6.88 seconds West; NAD 83. USGS Viola ID, WA topographic quadrangle.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon 20 to 38 inches, may include part of the Bw or Bt horizon
Depth to aquic conditions with chroma of 2 or less and redox concentrations 30 to 40 inches
Average annual soil temperature at 20 inches - 48 to 50 degrees F
Moisture control section saturated at certain seasons of the year but are dry for 45 to 60 consecutive days following the summer solstice in all parts between 4 and 12 inches in most years
Ap, A and AB horizons
Value - 3 to 5 dry, 1 to 3 moist
Chroma 1 to 3, moist or dry
Clay content 15 to 27 percent
Reaction slightly acid to slightly alkaline
Bw or Bt horizons
Hue 10YR or 2.5Y
Value - 4 to 6 dry, 2 to 5 moist
Chroma 1 to 3, moist or dry
Texture silt loam or silty clay loam
Structure Bt horizon, weak to moderate prismatic
Ped surface features faint to distinct discontinuous clay films are on vertical faces of some peds
Clay content 18 to 35 percent
Reaction neutral to moderately alkaline
Bg, Btg, and BCg horizons (absent in some pedons)
Hue 10YR or 2.5Y
Value - 4 to 7 dry, 2 to 4 moist
Chroma 1 to 4, moist or dry
Texture heavy silt loam or silty clay loam
Redoximorphic features faint to distinct with hues of 5YR to 10YR
Clay content 20 to 35 percent
Small pockets of volcanic ash and basalt pebbles are in the lower part of some profiles
Reaction neutral to moderately alkaline
Cg horizon present in some pedons
COMPETING SERIES: These are the Harana, Jett, Keigley, Loupence, Red Rock, Rustico and Snow series. Harana soils are strongly alkaline in the A horizon and are dry for more than 60 consecutive days. Jett and Keigley soils are calcareous and do not have aquic conditions within 40 inches. Loupence and Rustico soils have an aridic moisture regime. Red Rock soils are calcareous in the C horizon and do not have aquic conditions within 40 inches. Snow soils do not have aquic conditions with redoximorphic features with chroma of 2 or less within 40 inches.
GEOGRAPHIC SETTING: Caldwell soils are and on flood plains and drainageways. Slope ranges from 0 to 3 percent. The soils formed in fine-silty alluvium derived primarily from loess, with minor amounts of volcanic ash in the upper part. Elevations are 1,700 to 2,600 feet. The climate is characterized by warm dry summers and cool moist winters. The mean annual precipitation is 17 to 23 inches. The mean annual temperature is 47 to 49 degrees F. The frost-free period is about 100 to l35 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Konert, Latah, Naff, Palouse, and Thatuna soils. Konert soils have a fine textured argillic horizon and are on flood plains. Latah soils have albic horizon, a fine textured argillic horizon and are on low terraces and in drainageways. Naff and Thatuna soils do not have redox depletions or reduced matrix with a chroma of 2 or less and are on loess hills. Palouse soils have a regular decrease in organic carbon, do not have redoximorphic features and are on loess hills.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Permeability is moderately slow.
USE AND VEGETATION: These soils are used mainly for cropland. Small grains, peas, lentils, legumes and grass hay, and pasture are common crops. Native vegetation consisted of giant wildrye, sedge, bluegrasses, rushes, willow, hawthorn, cattails, redtop, iris, and aspen.
DISTRIBUTION AND EXTENT: Southeastern Washington and western Idaho; MLRA 9. Series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Boise Area, Idaho - 1901.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - the zone from 0 to 39 inches (Ap, A, ABt and Bt horizons)
Cumulic feature - the zone from 0 to 31 inches (Ap, A, and ABt and part of the Bt horizon) having an assumed irregular decrease in organic carbon with depth.
Cambic horizon - the zone from 39 to 54 inches (Btg horizon) with evidence of oriented clay but failing to meet the required clay increase.
Oxyaquic feature - a saturated zone from 30 to 40 inches having aquic conditions and chroma of 2 or less with redox concentrations.
Particle-size control section - the zone from 10 to 40 inches (part of the A, ABt, Bt and part of the Btg horizon)