LOCATION EMPIRE CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, isomesic Typic Kandihumults
TYPICAL PEDON: Empire loam - forested. (Colors for moist conditions unless otherwise noted).
A1--0 to 6 inches; dark reddish brown (5YR 3/4) loam, brown (7.5YR 5/3) dry; strong very fine granular structure; soft, friable, slightly sticky, slightly plastic; abundant very fine, and few fine and coarse roots; many very fine interstitial pores; strongly acid (pH 5.4); clear smooth boundary. (4 to 10 inches thick).
A3--6 to 12 inches; dark reddish brown (5YR 3/4) loam, brown (7.5YR 5/4) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; plentiful very fine, and few fine and coarse roots; many very fine interstitial and few fine tubular pores; few thin clay films in tubular pores; medium acid (pH 5.9); clear smooth boundary. (6 to 12 inches thick).
B1--12 to 22 inches; dark brown (7.5YR 4/3) heavy loam (near clay loam), same color dry; weak medium subangular blocky structure; slightly hard, friable, sticky, slightly plastic; plentiful very fine and few fine and coarse roots; many very fine interstitial and tubular, and few fine tubular pores; common moderately thick clay films occurring as bridges; medium acid (pH 5.8) gradual smooth boundary. (8 to 14 inches thick).
B2t--22 to 39 inches; yellowish brown (10YR 5/6) clay loam with reddish brown (5YR 5/4) coatings, yellowish brown (10YR 5/6) and brown (7.5YR 5/4) dry; weak coarse subangular blocky to massive; hard, firm, sticky, plastic; few fine and medium roots; many very fine and few fine tubular pores; many moderately thick clay films in pores and along fracture planes; very strongly acid (pH 5.0); gradual smooth boundary. (12 to 20 inches thick).
B31t--39 to 57 inches; yellowish brown (10YR 5/6) clay loam with dark reddish brown (5YR 3/4) coatings, yellowish brown (10YR 5/6) and strong brown (7.5YR 5/6) dry; massive; hard, firm, sticky, plastic; few very fine and medium roots; many very fine and few fine tubular pores; many moderately thick clay films in pores and few films along fracture planes; very strongly acid (pH 5.0) diffuse smooth boundary. (18 to 30 inches thick).
B32--57 to 66+ inches; yellowish brown (10YR 5/6) clay loam with dark reddish brown (5YR 3/4) coatings, yellowish brown (10YR 5/6) and strong brown (7.5YR 5/6) dry; massive; hard, firm, sticky, slightly plastic; few very fine and fine roots; common very fine tubular pores; common moderately thick clay films in pores and along fracture planes; strongly acid (pH 5.0); 10 to 20 inches thick. Grades into weathered, stratified, soft sedimentary rocks of varied color (yellow, brown, red) and texture (very fine sandy loam to silty clay loam).
TYPE LOCATION: Humboldt County, California. 0.5 miles east of Arcata on Fickle Hill Road, SE1/4, Sec. 28, T. 6N., R. 1E. Site is in a young-growth forest of Douglas-fir, grand fir, and redwood with understory of huckleberry, rhododendron, salal and sword fern on an upper slope, of 20 percent, west aspect, at an elevation of 450 feet.
RANGE IN CHARACTERISTICS: Separation of the horizons described is not always clear. The A1 and A3 horizons often appear as a thick A1 horizon. B1 and B2 horizons may appear as a continuous B2 horizon with gradual changes in color and structure with depth; B3 horizons could be called a C horizon. Colors and the amount of mottling due to ped face coatings, vary greatly in the subsoil because of stratification of the parent material. Hues of 7.5YR dominate throughout but range from 10YR to 5YR. Textures of the subsoil also vary greatly, ranging from very fine sandy loam to clay loams. Usually very fine sand can be felt in all horizons. Depth to a paralithic contact with parent rock ranges from 50-70 inches.
COMPETING SERIES: Included are the Hely, Larabee, and Goldridge soils. All are forested soils derived from soft sedimentary parent material. Hely soils are similar to Empire in color but have coarser textured cambic B horizons and have umbric epipedons. Larabee soils are grayer (10YR), with fine silty control sections and more massive subsoils. They occur on older, more uniformly textured, steep, dissected marine sediments. Goldridge soils are paler (10YR) throughout, and have argillic horizons.
GEOGRAPHIC SETTING: Empire soils occur on moderately steep, dissected old terraces with broad, relatively flat ridges and narrow drainages. Often the terrace shape is still recognizable. Slopes vary from 10-40 percent, dominantly 20-35 percent. Elevations range from near sea level to 1,500 feet. Climate is humid mesothermal, with cool, nearly rainless, very foggy summers, and cool wet winters. Annual rainfall is 35-70 inches. Annual temperature is 52 degrees F.; average January temperature is 47 degrees F.; average July temperature is 56 degrees F. Frost-free season is more than 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: Included are the Caspar, Hely, Larabee, and Tonini soils. All are forested soils derived from similar soft sedimentary rocks.
DRAINAGE AND PERMEABILITY: Well to moderately well drained; runoff slow to medium; permeability moderately rapid to slow. In "flat" areas drainage may be slow, and permeability reduced because of stratification of the parent material; temporary ponding is not uncommon in such areas.
USE AND VEGETATION: Coniferous forest; redwood, Douglas-fir, grand fir, coast hemlock and some Sitka spruce with understories of rhododendron, huckleberry, salal, and sword fern. Considerable areas have been cutover at least once and little old-growth remains. Some areas have been converted to pasture or cultivated crops. Red alder often dominates cutover sites but eventually is replaced by conifers. Productivity for timber is very high (site index 180 for Douglas-fir). Productivity for forage rates medium.
DISTRIBUTION AND EXTENT: Soft sedimentary rocks along the north coast of California and southern Oregon. The soils are moderately extensive (about 40,000 acres).
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Marshfield area, Coos and Curry Counties, Oregon, 1909.
REMARKS: The Empire series was formerly classified in the Yellowish Brown Lateritic (1938 USDA yearbook), and brown Podzolic (Storie and Weir). As originally mapped in the Eureka area of Humboldt County in 1925, the Empire soils included soils which are now separated as the Hely and Tonini series. Types originally mapped as Empire fine sandy loam closely approximate this revision. In this revised description, Empire soils have an ochric epipedon and a cambic horizon, and base saturation of less than 35 percent above the paralithic contact.
OSED scanned by SSQA. Last revised by state on 4/67.