LOCATION CHANCE ID+UTEstablished Series
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, nonacid, mesic Mollic Endoaquepts
TYPICAL PEDON: Chance fine sandy loam, sedges and grass. (Colors are for dry soil unless otherwise noted.)
A1g--0 to 6 inches; gray (2.5Y 5/1) fine sandy loam, very dark gray (2.5Y 3/1) moist; many fine and medium distinct olive (5Y 5/3) mottles; weak fine granular structure; slightly hard, friable, slightly sticky; many roots; many very fine pores; neutral (pH 6.8); gradual smooth boundary. (4 to 8 inches thick)
Bg--6 to 31 inches; gray (2.5Y 5/1) fine sandy loam, dark gray (2.5Y 4/1) moist; common fine and medium prominent brown (7.5YR 5/3) mottles; very fine subangular blocky structure; slightly hard, friable, slightly sticky; common fine roots; many very fine pores; neutral (pH 6.9); abrupt smooth boundary. (14 to 30 inches thick)
IICIg--31 to 35 inches; gray (N 6/) loamy fine sand, dark gray (N 4/) moist; common fine faint pale brown (10YR 6/3) mottles; single grained; loose; neutral (pH 6.7); abrupt smooth boundary. (0 to 5 inches thick)
IIIC2--35 to 60 inches; stratified sand and gravel; single grained; loose; neutral.
TYPE LOCATION: Gem County, Idaho; about 0.5 mile east of Emmett; 250 feet south and 150 feet east of the northwest corner of the SW1/4 sec. 5, T. 6 N., R. 1 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches is estimated to range from 47 degrees to 54 degrees F., and the mean summer temperature from 66 degrees to 71 degrees F. The soil is saturated with water much or all of the year unless artificially drained. It is neutral or mildly alkaline. Strongly contrasting loose sand and gravel is at depths of 20 to 40 inches. The soil between depth of 10 inches and the sand and gravel is dominantly fine sand loam or sandy loam and average less than 18 percent, less than 50 percent is fine and coarser sand, and less than 15 percent gravel and coarser fragments. The organic matter content is moderately low or moderate and decreases regularly as depth increases to less than 0.35 percent at some depth of less than 50 inches.
The A horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry, 3 or 4 moist and chroma of 0.5 to 1.5. If the A horizon is darker than value of 5.5 dry and 3.5 moist, it is less than one-third and thickness of the solum. Mottles in the A horizon range from faint to distinct.
Below the A horizon, 2.5Y hue is dominant, but in some pedons hue if 10YR, 5Y or is lacking (N). The B horizon is mottled, and chroma of the matrix ranges from 0.5 to 1.5.
COMPETING SERIES: This is the Halsey series. Halsey soils have an A horizon 10 to 19 inches thick, part of which is an A2 horizon.
GEOGRAPHIC SETTING: The Chance soils are in low areas, old channels, or swales on bottom lands and low terraces at elevations of 2,000 to 4,000 feet. Slopes are dominantly less than 1 percent and range from 0 to 3 percent. The soils formed in recent alluvium dominantly from granite, but they contain a small amount of material from basalt. The frost-free period ranges from 110 to 160 days. The mean annual precipitation ranges from 8 to 13 inches, including 1.5 to 3 feet of snow.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Emerson, Falk, Moulton and Notus soils. Emerson soils are usually dry and lack mottles. Notus soils have sand and gravel at depths of less than 20 inches. Falk soils have chroma of 2 or 3, and they lack mottles at depths of less than 20 inches. Moulton soils have chroma of 2 or 3 and they lack mottles at depths of less than 8 inches.
DRAINAGE AND PERMEABILITY: Poorly or very poorly drained; very slow runoff or ponded; moderately rapid permeability. The water table is at depths of less than 10 inches. These soils are flooded annually during the months of February through June.
USE AND VEGETATION: Mostly for pasture. The dominant vegetation is tues, sedges, cattails, rushes, and water-loving grasses; a little saltgrass is in higher positions.
DISTRIBUTION AND EXTENT: Southwestern Idaho and possibly in adjacent states. The series is of small extent; the total known area is about 5,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gem County, Idaho, 1949.