LOCATION VAN HORN OREstablished Series
SOIL FAMILY: Fine-loamy, mixed, mesic Ultic Argixerolls
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Van Horn fine sandy loam, cultivated. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) fine sandy loam, grayish brown (10YR 5/2) dry; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine irregular pores; many very fine roots; slightly acid (pH 6.4); clear smooth boundary. (4 to 8 inches thick)
A3--7 to 14 inches; dark brown (10YR 3/3) fine sandy loam, grayish brown (10YR 5/3) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine tubular pores; many very fine roots; slightly acid (pH 6.4); gradual smooth boundary. (0 to 10 inches thick)
B1--14 to 22 inches, brown (10YR 4/3) fine sandy loam, light brownish gray (10YR 6/2) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine tubular pores; many very fine roots; slightly acid (pH 6.4); clear smooth boundary. (7 to 12 inches thick)
B21t--22 to 35 inches; dark yellowish brown (10YR 4/4) sandy clay loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine tubular pores; many very fine roots; few thin clay films on peds and common moderately thick clay films in pores; slightly acid (pH 6.4); gradual smooth boundary. (8 to 18 inches thick)
B22t--35 to 61 inches; dark yellowish brown (10YR 4/4) sandy clay loam, pale brown (10YR 6/3) dry; moderate medium subangular blocky structure; hard, friable, sticky and slightly plastic; many very fine tubular pores; many very fine roots; few thin clay films on peds and common moderately thick clay films in pores; few black stains on peds; thin gray coatings of sand grains on faces of peds and in pores; slightly acid (pH 6.4); gradual smooth boundary. (8 to 15 inches thick)
C--61 to 72 inches; dark brown (10YR 4/3) sandy loam, pale brown (10YR 6/3) dry; massive; slightly hard, very friable, slightly sticky and slightly plastic; many very fine tubular pores; few very fine roots; slightly acid (pH 6.2).
TYPE LOCATION: Hood River County, Oregon; NE1/4 SW1/4 SW1/4 sec. 1, T.2N., R.10E.
RANGE IN CHARACTERISTICS: The soils are usually moist but are dry throughout the control section for 60 to 80 consecutive days during the 4-month period following summer solstice. Mean annual soil temperature ranges from 51 degrees to 54 degrees F. The solum is 40 to 60 inches thick. The mollic epipedon is 10 to 20 inches thick. The profile contains many clear mica particles. The soils are neutral or slightly acid.
The A horizon has hue of 10YR or 7.5YR and chroma of 2 or 3 moist and dry. It is very fine sandy loam, fine sandy loam or loam.
The B2 horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 through 4 moist and dry. It is clay loam or sandy clay loam and has 22 to 35 percent clay. This horizon has weak or moderate structure.
The C horizon has hue of 2.5Y or 10YR, value of 5 or 6 dry, and chroma of 3 or 4 moist and dry. It is loam, sandy loam or loamy sand.
COMPETING SERIES: These are the Brownlee, Domingo, Felton, Goldendale and Schumacher series. Brownless soils have sola 25 to 50 inches thick, mean annual soil temperature of 47 degrees to 52 degrees F., are moderately high in coarse and very coarse sand, have a freeze-free period of less than 150 days, and have decomposing granitic bedrock at depths of 40 to 60 inches. Domingo soils are medium to strongly acid in the B2t horizon and are somewhat poorly and moderately well-drained and mottled in the B and C horizons. Felton soils have less than 20 degrees F. difference in the mean winter and mean summer soil temperature and have a mean annual soil temperature of 56 degrees F. Goldendale soils have B horizons with strong structure and very hard and very firm consistence. Schumacher soils are gravelly in the argillic horizons and have A2 horizons above the argillic horizon.
GEOGRAPHIC SETTING: Van Horn soils are on nearly level to steep slopes with gradients up to 35 percent and at elevations of 100 to 850 feet. The soils formed in stratified alluvial deposits and moderately coarse and coarse glacial outwash weathered dominantly from basic igneous rocks. The climate is subhumid with a mean annual precipitation of 20 to 35 inches. Summers are warm and dry with an average July temperature of 67 degrees F. Winters are cool and wet with an average January temperature of 33 degrees F. The mean annual temperature is 49 degrees to 52 degrees F. The frost-free period (32 degrees F.) is 150 to 180 days and for 28 degrees F. is 180 to 210 days.
ASSOCIATED SOILS: These are the Chenoweth, Cherryhill, Hood, Rockford and Wind River soils. Chenoweth and Wind river soils are coarse-loamy. Cherryhill soils lack mollic epipedons. Hood soils have ochric epipedons. Rockford soils contain more than 50 percent rock fragments.
DRAINAGE AND PERMEABILITY: Well-drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Principal use is for tree fruit crops. Other uses are for growing strawberries and hay and pasture. Native vegetation is mainly Douglas-fir and ponderosa pine.
DISTRIBUTION AND EXTENT: North-central Oregon. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wasco County, Oregon, 1975.