LOCATION MCKENNA WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, mesic Aquandic Epiaquepts
TYPICAL PEDON: McKenna gravelly ashy loam - woodland. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed twigs, needles, bark and wood fragments; abrupt wavy boundary.
Oe--1 to 3 inches; moderately decomposed needles, leaves and wood; abrupt wavy boundary.
A--3 to 9 inches; dark reddish brown (5YR 2/2) gravelly ashy loam, dark gray (10YR 4/1) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many coarse, medium and fine roots; 20 percent gravel; strongly acid; abrupt smooth boundary. (4 to 9 inches thick)
Bwl--9 to 11 inches; dark grayish brown (10YR 4/2) gravelly ashy silt loam, grayish brown (10YR 5/2) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few coarse, medium and fine roots; 25 percent gravel; strongly acid; clear smooth boundary. (2 to 6 inches thick)
Bw2--11 to 19 inches; grayish brown (10YR 5/2) very gravelly loam, light brownish gray (10YR 6/2) dry; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; very few fine roots; 40 percent gravel; moderately acid; gradual smooth boundary. (4 to 15 inches thick)
Bg--19 to 31 inches; dark grayish brown (10YR 4/2) very gravelly loam, light brownish gray (2.5Y 6/2) dry; common medium distinct strong brown (7.5YR 5/8) redox concentrations; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; 45 percent gravel; moderately acid; abrupt smooth boundary. (6 to 15 inches thick)
Cdl--31 to 40 inches; grayish brown (2.5Y 5/2) dense glacial till that crushes to very gravelly loam, light gray (5Y 7/1) dry; common medium distinct dark olive gray (5Y 3/2) and yellowish brown (10YR 5/4) redox features; compact; hard, firm, nonsticky and nonplastic; 45 percent gravel; moderately acid; abrupt smooth boundary.
Cd2--40 to 63 inches; dark greenish gray (5BG 4/1) dense glacial till that crushes to gravelly silty clay, gray (N/6) dry; massive; compacted glacial till, extremely hard, firm, very sticky and very plastic; moderately acid.
TYPE LOCATION: Kitsap County, Washington; 1,900 feet east and 1,150 feet south of the northwest corner of sec. 1, T. 22 N., R. 1 E.
RANGE IN CHARACTERISTICS: Solum thickness and depth to the densic contact with dense very compact glacial drift range from 20 to 40 inches. The particle-size control section averages 35 to 60 percent coarse fragments and 20 to 35 percent clay. The upper 7 to 14 inches of the solum has 5 to 12 percent glass and acid oxalate extractable aluminum plus one-half the iron of 0.4 to 1.0 percent. Depth to redox concentrations with depletions of 2 or less is 10 to 20 inches.
The A horizon has hue of 5YR, 7.5YR, or 10YR, value of 2 or 3 moist, 2 through 5 dry, and chroma of 1 or 2. it is very strongly acid to moderately acid.
The Bw horizon has hue of 7.5YR or 10YR, value of3 to 5 moist, 5 or 6 dry and chroma of 2. It is silt loam or lo0am with 20 to 50 percent gravel.
The Bg horizon has hue of 10YR, 2.5Y, or 5Y, value of 3 through 6 moist, 5 through 8 dry, and chroma of 1 or 2. It has coarse prominent to fine faint redox concentrations. It is clay loam or loam and has 35 to 60 percent coarse fragments. It is strongly acid or moderately acid.
The Cd horizon has hue of 10YR, 2.5Y, BG or N., value of 4 through 6 moist, 6 through 8 dry, and chroma of 0 through 3. It has redox features in most pedons. It is dense compact glacial till that crushes to gravelly, very gravelly or extremely gravelly sandy loam, loam, clay loam, silty clay loam or silty clay. It is moderately acid or slightly acid.
COMPETING SERIES: This is the closely related Bellingham series. Bellingham soils have more than 35 percent clay and lack coarse fragments.
GEOGRAPHIC SETTING: McKenna soils are in depressions and drainageways at elevations of 50 to 500 feet. Slopes are 0 to 5 percent. The soils formed in glacial drift. The climate is marine having an average annual precipitation of 30 to 60 inches and most of it falls as rain during the winter. The mean annual temperature is about 50 degrees F. and the frost-free season is 150 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alderwood, Catla, Clallam, Elwha, Hoypus, Kapowsin, Neilton, Yeary and the competing Bellingham soils. All of these soils lack an aquic moisture regime except the competing Bellingham soils. Also, Alderwood and Kapowsin soils have a cemented layer. Hoypus and Neilton soils lack the densic contact.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow or slow runoff, or ponded; permeability is slow in the B horizon and very slow through the Cd horizon. A perched water table is at or near the surface during the November to March rainy season unless drained and water ponds on the surface in many areas.
USE AND VEGETATION: Mostly used for woodland. Some areas are cleared and used for grass pasture. Native vegetation is red alder, willow, western redcedar, and western hemlock, with an understory of salmonberry, sedges, Douglas spirea, forbs and water tolerant grasses.
DISTRIBUTION AND EXTENT: Throughout the Puget Sound Basin of western Washington; MLRA 2. This series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Whatcom County, Washington, 1945.
REMARKS: Diagnostic horizons and other features are:
Ochric epipedon
Cambic horizon - 9 to 31 inches
Aquandic subgroup - 3 to 11 inches
All depths to diagnostic horizons or other features are measured from the top of the first mineral horizon.