LOCATION GRAVDEN OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Xeric Haplodurids
TYPICAL PEDON: Gravden very gravelly loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A11--0 to 3 inches; pale brown (10YR 6/3) very gravelly loam, dark brown (10YR 3/3) moist; weak fine and medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine irregular pores; 25 percent pebbles, 10 percent cobbles; moderately alkaline (pH 8.0); clear wavy boundary.
A12--3 to 7 inches; pale brown (10YR 6/3) very gravelly loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; 30 percent pebbles, 10 percent cobbles; thin (1/8 inch) lime coatings on underside of pebbles; moderately alkaline (pH 8.0); clear wavy boundary. (3 to 6 inches thick)
C1ca--7 to 14 inches; light yellowish brown (10YR 6/4) extremely gravelly loam, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; 55 percent pebbles; 10 percent cobbles; lime coated on all surfaces; thick (1/8 to 1/4 inch) lime coatings on underside of pebbles; moderately calcareous; moderately alkaline (pH 8.2); clear irregular boundary. (5 to 15 inches thick)
IIC2casim--14 to 20 inches; very gravelly duripan; massive; indurated very firm; 1 to 20 silica laminar capping on surface; strongly calcareous; root mat on pan surface.
IIC3sim--20 to 60 inches; similar to above but stratified strongly and weakly cemented layers.
TYPE LOCATION: Morrow County, Oregon; about 55 feet south of farm road in the NE1/4 NE1/4 SW1/4 section 19, T.2N., R.27E.
RANGE IN CHARACTERISTICS: The soils are dry in all parts more than half the time (cumulative) that the soils temperature is above 41 degrees F. b.t are moist in some part of the soil between depths of 8 and 24 inches for more than 1/4 of the time (cumulative) that the soil temperature exceeds 41 degrees F. and are moist during the winter. The mean annual soil temperature is 50 to 56 degrees F. Depth to the duripan ranges from 10 to 20 inches. Depth to bedrock is more than 60 inches.
The A horizon has value of 3 or 4 moist, and chroma of 2 or 3 moist and dry. It is silt loam, loam, or fine sandy loam and has 20 to 35 percent pebbles and 0 to 10 percent cobbles.
The c horizon has value of 4 or 5 moist and chroma of 3 or 4 moist and dry. It has 35 to 70 percent pebbles and 5 to 15 percent cobbles. This horizon is moderately or strongly calcareous.
The duripan is indurated in the upper part and weakly to strongly cemented below and has 35 to 80 percent pebbles.
COMPETING SERIES: These are the Bliss, Bunky, Ellum, Jacquith, Lofftus, Morehouse and Rubyhill series in other families. Bliss, Bunky, Jacquith, Lofftus, Morehouse and Rubyhill soils have less than 35 percent rock fragments in their control section and all except Morehouse have mesic soil temperature and are deeper than 20 inches to the duripan. Also, Morehouse soils are sandy. Ellum soils are deeper than 20 inches to the duripan.
GEOGRAPHIC SETTING: Gravden soils are on terraces and have generally south facing slopes of 4 to 40 percent. Elevations are 500 to 1,700 feet. Gravden soils formed in gravelly alluvium mixed with wind lain materials in the upper part. Climate is semiarid with a mean annual precipitation of 9 to 12 inches. The mean annual temperature is 48 to 54 degrees F.; the mean winter temperature is about 35 degrees F.; the mean summer temperature is about 60 to 72 degrees F. The frost free season is 120 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blalock, Olix, Ritzville and Warden soils. Blalock, Olex and Ritzville soils have mollic epipedons. Blalock soils alos have less than 35 percent rock fragments. Olex, Ritzville and Warden soils lack duripans. Ritzville and Warden soils are deep silt loam soils lacking rock fragments.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate rapid permeability to the duripan and very slow in the duripan.
USE AND VEGETATION: Rangeland. Present vegetation is mainly bluebunch wheatgrass, Sandberg bluegrass, cheatgrass and gray and green rabbitbrush.
DISTRIBUTION AND EXTENT: Uplands of north central Oregon and in Utah. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Morrow County, Oregon, 1977.
NSTH 17, RECLASSIFICATION ONLY, 3/95