LOCATION PODEN OR+IDEstablished Series
TAXONOMIC CLASS: Fine-silty over sandy or sandy-skeletal, mixed, superactive, mesic Cumulic Haploxerolls
TYPICAL PEDON: Poden silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; moderate thin platy parting to moderate fine granular structure; soft, very friable, nonsticky and slightly plastic; many fine roots; many very fine irregular pores; moderately alkaline (pH 8.2); abrupt smooth boundary. (5 to 9 inches thick)
A12--7 to 13 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many roots; many very fine tubular pores; moderately alkaline (pH 8.2); gradual wavy boundary. (4 to 10 inches thick)
B2--13 to 22 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic parting to moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; moderately alkaline (pH 8.2); gradual wavy boundary. (5 to 15 inches thick)
C1--22 to 30 inches; grayish brown (10YR 5/2) heavy silt loam, very dark grayish brown (10YR 3/2) moist; massive; hard, friable, sticky and plastic; many roots; few fine tubular pores; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 10 inches thick)
IIC2--30 to 50 inches; multicolored very gravelly sand; single grained; loose; few roots in the upper few inches; many pores.
TYPE LOCATION: Malheur County, Oregon; 40 feet north of concrete irrigation control structure; NE1/4 SW1/4 SW1/4 section 7, T. 20 S., R. 42 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 48 to 56 degrees F. The soils are usually dry but are moist in some part between depths of 4 and 12 inches for a cumulative period equal to more than one quarter of the time that the soil temperature exceeds 41 degrees F., and are moist for more than 60 days during the winter season and are dry for 45 consecutive days or more within the four month period following the summer solstice. Depth to the stratified very gravelly sand ranges from 15 to 40 inches but most commonly is 17 to 32 inches.
The solum is moderately alkaline and commonly noncalcareous but some pedons are weakly calcareous throughout. The solum is silt loam, loam or light silty clay loam and has 18 to 35 percent clay but usually less than 25 percent clay and less than 15 percent fine sand and coarser. The solum has value of 2 or 3 moist and chroma of 2 or 3 dry and moist.
In some pedons the C1 horizon has up to 20 percent pebbles. The IIC2 horizon ranges from 35 to 70 percent pebbles.
COMPETING SERIES: These are the Jett, Pattit Creek, Snow, Veazie, and Yakima series. Jett, Pattit Creek, and Snow soils lack contrasting textures within the upper 40 inches. Also, Pattit Creek soils are coarse-loamy and usually moist. Snow soils also are usually moist. Veazie and Yakima soils are coarse-loamy over sandy or sandy-skeletal.
GEOGRAPHIC SETTING: Poden soils are on nearly level to gently sloping alluvial floodplains and low fans with gradients of 0 to 5 percent but commonly less than 2 percent at elevations of 2,400 to 3,200 feet. The soils formed in mixed alluvium weathered from basic igneous rocks and old lacustrine sediments. The climate is semiarid and has hot dry summers and cold winters. Mean annual precipitation is 8 to 11 inches. The mean annual temperature is about 46 to 52 degrees F., mean summer temperature is 68 to 72 degrees F., and the mean winter temperature is 31 to 33 degrees F. The frost-free period ranges from 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Powder, Stanfield and Umapine series. Powder soils are coarse-silty and lack contrasting textures. Stanfield soils are very strongly alkaline and have a duripan at depths of 20 to 40 inches. Umapine soils are coarse-silty and very strongly alkaline.
DRAINAGE AND PERMEABILITY: Well and moderately well drained; slow runoff; moderate permeability.
USE AND VEGETATION: Used for production of irrigated crops and as rangeland. Corn, potatoes, small grain, alfalfa hay and pasture are grown under irrigation. Native plants are mainly giant wild ryegrass, Sandberg bluegrass, big sagebrush, rabbitbrush and annual forbs. DISTRIBUTION AND EXTENT: Malheur County, Oregon. The series is of small extent.
SERIES ESTABLSIHED: Malheur County, Oregon, 1975.