LOCATION DONAVAN WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Donavan ashy loam - forested. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; partially decomposed needles and twigs.
A--1 to 8 inches; grayish brown (10YR 5/2) ashy loam, very dark brown (10YR 2/2) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; 2 percent gravel; slightly acid (pH 6.4); clear wavy boundary. (5 to 15 inches thick)
Bw--8 to 15 inches; brown (10YR 5/3) ashy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many fine and very fine roots; 2 percent gravel; slightly acid (pH 6.4); abrupt wavy boundary. (7 to 20 inches thick)
2BC--15 to 29 inches; pale yellow (2.5Y 7/4) gravelly loam, olive brown (2.5Y 4/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; few fine and medium roots; 25 percent gravel; neutral (pH 6.7); gradual wavy boundary. (0 to 20 inches thick)
2Cd--29 to 60 inches; light gray (2.5Y 7/2) gravelly loam, light olive brown (2.5Y 5/4) moist; massive; hard, firm, slightly sticky and slightly plastic; few fine and medium roots; 25 percent gravel; neutral (pH 6.7).
TYPE LOCATION: Ferry County, Washington; 925 feet south and 925 feet west of the northeast corner of sec. 21, T. 36 N., R. 37 E., (Latitude 48 degrees, 36 minutes, 31.98 seconds North, Longitude 118 degrees, 09 minutes, 18.89 seconds West [NAD83].).
RANGE IN CHARACTERISTICS:
Soil Moisture: The soils are usually moist but are dry for 75 to 90 consecutive days following the summer solstice (xeric soil moisture regime).
Soil Temperature: mean annual soil temperature is 47 to 51 degrees F.
Rock fragments: average from 10 to 35 percent in the particle-size control section. Some pedons have a stony or bouldery surface
Depth to a densic contact: 20 to 40 inches.
Clay content: averages 5 to 15 percent in the particle-size control section
Vitrandic soil properties: upper 12 to 25 inches has an estimated moist bulk density of 1.10 to 1.40 g/cc, volcanic glass content of 5 to 20 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.4 to 1.0 percent, and 15-bar water retention of 5 to 12 percent for air dried samples
Mollic epipedon: 7 to 20 inches in thickness. When less than 10 inches, the epipedon is 1/3 or more as thick as the solum.
A horizon
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3 moist
Reaction: moderately acid to neutral
AB horizon (when present)
Value: 4 or 5 dry, 3 moist
Chroma: 2 or 3 moist or dry
Texture: loam, sandy loam, or silt loam
Gravel: 5 to 15 percent
Cobbles: 0 to 5 percent
Bw horizon
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 to 4 dry or moist
Texture: loam, silt loam, sandy loam, gravelly loam, gravelly silt loam, gravelly sandy loam, cobbly loam, or cobbly sandy loam
Gravel: 5 to 20 percent
Cobbles: 0 to 15 percent
Reaction: slightly acid or neutral
2BC horizon is absent in some pedons.
2Cd horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 2 to 4 dry or moist
Texture: gravelly loam, gravelly silt loam, gravelly sandy loam, gravelly coarse sandy loam, or cobbly sandy loam
Gravel: 10 to 25 percent
Cobbles: 0 to 15 percent
Stones: 0 to 5 percent
Reaction: slightly acid or neutral
COMPETING SERIES: These are the Fourmound, Goldlake, Monkeycreek, Seaboldt (T), Spokane and Usk series. Fourmound soils are 40 to 60 inches to a lithic contact. Goldlake soils have a mollic epipedon 20 to 28 inches thick and have densic material at 40 to 60 inches. Spokane, and Usk soils have a paralithic contact at 20 to 40 inches. Monkeycreek soils are very deep. Seaboldt series have a lithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Donavan soils are on toeslopes, footslopes and backslopes of glaciated foothills and mountains. Slope ranges from 0 to 65 percent. These soils formed in mixed volcanic ash over glacial till. Elevations are 1,800 to 4,500 feet. The climate is characterized by warm, dry summers and cool, moist winters. The mean annual precipitation is 14 to 20 inches. Mean January temperature is about 24 degrees F, mean July temperature is about 66 degrees F, and the mean annual air temperature is 45 to 50 degrees F. The frost-free season is 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bernhill, Borgeau, Dehart, Maki, Molcal, Molson, Nevine, Raisio, Republic, Rufus, Scoap, Stevens, and Vallan soils. Bernhill soils are fine-loamy and are on glaciated foothills and glaciolacustrine influenced ground moraines. Borgeau, Dehart, Maki, Nevine, Raisio, Rufus, and Scoap soils are loamy-skeletal. Borgeau soils are on backslopes of hills. Dehart soils are on mountains. Maki soils are on south-facing glaciated uplands and mountainsides. Nevine soils are on moraines, foothills and mountains. Raisio and Rufus soils are on footslopes, sideslopes, and ridgetops of mountains. Scoap soils are on uplands and mountains. Molcal soils have 2Bk horizons and are on uplands. Molson soils are ashy over loamy. Republic soils have a mean soil temperature of 44 to 46 degrees F and are on alluvial fans, terraces and footslopes and backslopes of mountains. Vallan soils are 10 to 20 inches deep to a lithic contact and are on summits, shoulders, and backslopes of glacially scoured foothills and mountains.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderate over slow permeability.
USE AND VEGETATION: Used for cropland, hay and pasture, timber production, grazing and wildlife habitat. Native vegetation is ponderosa pine and Douglas-fir with an understory of common snowberry, blue wildrye, pinegrass, creeping Oregon-Grape, Saskatoon serviceberry, and woods rose. Warm phases have a ponderosa pine overstory and an understory of Idaho fescue, bluebunch wheatgrass, antelope bitterbrush, arrowleaf balsamroot, silky lupine, and white spirea.
DISTRIBUTION AND EXTENT: Northcentral and northeastern Washington. MLRA 43A, 6. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: North Ferry Area, Ferry County, Washington, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - the zone from 1 to 15 inches (the A and Bw horizons)
Cambic horizon - the zone from 15 to 29 inches (the 2BC horizon)
Particle-size control section - the zone from 11 to 29 inches (part of the Bw and the 2BC horizon)
Rock fragments - 22 percent coarse fragments in the particle-size control section.
Base saturation: (by sum of cations) is less than 75 percent in parts of the upper 30 inches of the soil.
The 11/2008 description reflects a change in classification from coarse-loamy, mixed, mesic Vitrandic Haploxerolls to coarse-loamy, isotic, mesic Vitrandic Haploxerolls.
ADDITIONAL DATA: Characterization data are available on pedon number 84P173 and partial lab data are available National Soil Survey Laboratory Sample number 69267-69272.