LOCATION DONNARDO UT+IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Calcixerolls
TYPICAL PEDON: Donnardo very stony loam, rangeland. (Colors are for air-dry soil unless otherwise noted)
A1--0 to 2 inches; brown (10YR 4/3) very stony loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; slightly hard, friable, slightly plastic; many very fine and few fine roots; common fine pores; 10 to 25 percent of the surface is covered with stones and cobbles and 40 percent stones in the matrix; slightly calcareous; carbonates are disseminated; mildly alkaline (pH 7.4); abrupt smooth boundary. (2 to 3 inches thick)
A2--2 to 10 inches; brown (10YR 5/3) very stony loam, very dark brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and common medium roots; common fine and medium pores; 50 percent stones and cobbles; slightly calcareous; carbonates are disseminated; mildly alkaline (pH 7.6); gradual smooth boundary. (3 to 10 inches thick)
A3--10 to 15 inches; brown (10YR 5/3) very cobbly loam, dark brown (10YR 3/3) moist; moderate medium and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few medium and fine roots; common medium and few fine pores; 45 percent cobbles and pebbles; moderately calcareous; carbonates are disseminated; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 6 inches thick)
Bk1--15 to 30 inches; very pale brown (10YR 7/3) very stony loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and plastic; few medium and fine roots; few medium and common fine pores; common krotovina; 50 percent stones and cobbles; strongly calcareous; carbonates are disseminated, in veins and fine soft rounded accretions; strongly alkaline (pH 8.6); clear wavy boundary. (12 to 20 inches thick)
Bk2--30 to 41 inches; pale brown (10YR 6/3) very stony loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; few medium and few fine roots; common medium and common fine pores; 60 percent cobbles and stones; strongly calcareous; carbonates are disseminated and in fine veins and coatings on rock fragments; strongly alkaline (pH 8.6); clear wavy boundary. (10 to 15 inches thick)
Bk3--41 to 60 inches; pale yellow (2.5Y 7/3) extremely stony loam, light olive brown (2.5Y 5/3) moist; massive; hard, friable, slightly sticky and plastic; few fine and few very fine roots; few fine and common very fine pores; 70 percent stones and cobbles; strongly calcareous; carbonates are disseminated and in soft, fine coatings on rock fragments; strongly alkaline (pH 8.6).
TYPE LOCATION: Sanpete County, Utah; about 3 miles east of Spring City, near the mouth of Oak Creek Canyon; about 2,970 feet east of the SW corner of sec. 35, T. 15 S., R. 4 E.
RANGE IN CHARACTERISTICS: Rock fragments in the particle-size control section range from 35 to 70 percent, and range from gravel to stones. There are layers of cobbles or stones in some part of the series control section. Depth to the calcic horizon ranges from 8 to 19 inches. The mean annual soil temperature at 20 inches ranges from 47 to 54 degrees F. The mean summer soil temperature ranges from 64 to 66 degrees F. The moisture control section is dry for 60 to 80 consecutive days during the summer and moist for 60 to 70 consecutive days during the 120 days after the winter solstice.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. It is slightly alkaline to strongly alkaline, and slightly calcareous to strongly calcareous.
The Bk horizon has hue of 7.5YR through 2.5Y, value of 6 through 8 dry, 4 through 6 moist, and chroma of 2 through 4. It is very gravelly loam, extremely gravelly loam, very cobbly loam, very stony loam, extremely stony loam or very cobbly sandy loam. It is moderately alkaline to strongly alkaline, and contains 15 to 40 percent calcium carbonate.
COMPETING SERIES: These are the Munk (UT), Stember (WA), and Sterling (UT) series. Munk and Stember soils are 20 to 40 inches deep over bedrock. Sterling soils have only gravel sized rock fragments in the series control section.
GEOGRAPHICAL SETTING: Donnardo soils are on moderately sloping to moderately steep alluvial fans. They formed in alluvium from sandstone, limestone and shale. These soils occur at elevations of 4,500 to 6,600 feet and are on south or west exposures above 6,200 feet. Slopes are 2 to 40 percent. The climate is dry subhumid and the average annual precipitation ranges from 12 to 16 inches. Mean annual temperature ranges from 45 to 52 degrees F. Freeze-free period is 110 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Birdow, Borvant, Collard, Denmark, Doyce, Keigley, Mountainville and Pavant soils and the competing Fontreen soils. Birdow and Keigley soils lack calcic horizons, and have less than 35 percent rock fragments. Borvant, Denmark and Pavant soils have petrocalcic horizons at depths of less than 20 inches. Collard, Doyce and Mountainville soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used for range. Potential vegetation is bluebunch wheatgrass, big sagebrush, bluegrass and needleandthread.
DISTRIBUTION AND EXTENT: Central Utah. The series is inextensive. MLRA 28A and 47.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sanpete County, Utah, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface of the soil to 15 inches. A1, A2, and A3 horizons)
Calcic horizon - the zone of calcium carbonate accumulation from 15 to 60 inches. (Bk1, Bk2, and Bk3 horizons)
In July 1995 the classification was changed from Aridic Calcixeroll to Typic Calcixeroll. This was based on the precipitation of up to 16 inches per year, the Upland range site and dry matter production. As a result of this classification change the Sterling series and Donnardo series are in the same family and it appears that Utah had two series to accomodate the same concept. This was not recognized because they were under two classifications. At this time it is inappropriate to drop one of the series because they have both been correlated in a number of surveys. In reviewing each of the 9 survey type locations there appears to be a natural separation between the pedons confined to gravel sized rock fragments and and the pedons that contain cobble or stone sized fragments. This would provide suitable series differentia and it results in significant interpretive differences. In updating surveys some units of Sterling would be recorrelated to Donnardo.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Lakewood MLRA office, without review of the soil series property data. The remainder of this document has not been updated.