LOCATION BUMBOB WYEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, mesic Ustertic Haplocambids
TYPICAL PEDON: Bumbob clay-on a southwest facing slope of two percent; utilized as rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 3 inches; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; weak coarse granular structure parting to strong fine granular; hard, firm, very sticky and very plastic; few coarse and common medium and fine roots; strongly acid (pH 5.2); clear wavy boundary. (2 to 6 inches thick)
Bw1--3 to 9 inches; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; moderate medium angular blocky structure; very hard, very firm, very sticky and very plastic; common distinct pressure faces on vertical faces of peds; few coarse, medium, and fine roots; very strongly acid (pH 4.9); clear wavy boundary.
Bw2--9 to 19 inches; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; moderate medium and fine angular blocky structure; very hard, very firm, very sticky and very plastic; common distinct pressure faces on vertical faces of peds; few coarse, medium, and fine roots; extremely acid (pH 4.0); clear wavy boundary. (Combined thickness of Bw is 5 to 23 inches)
C1--19 to 36 inches; pale brown (10YR 6/3) clay, brown (10YR 5/3) moist; massive; very hard, very firm, very sticky and very plastic; few fine roots; extremely acid (pH 3.8); gradual irregular boundary. (17 to 41 inches thick)
C2--36 to 60 inches; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; massive; very hard, firm, very sticky and very plastic; extremely acid (pH 3.6).
TYPE LOCATION: Niobrara County, Wyoming; about 500 feet north and 800 feet east of the southwest corner of sec. 28, T. 38 N., R. 61 W. 43 degrees 14 minutes 07 seconds north latitude and 104 degrees 12 minutes 00 seconds west longitude.
RANGE IN CHARACTERISTICS: Depth to the base of the cambic horizon is 11 to 25 inches. The mean annual soil temperature is 47 to 51 degrees F. Coarse fragments in the form of hard fine shale channers are typically less than 5 percent but range from 0 to 15 percent. The soil is dry in the moisture control section more than half the time cumulative that the soil temperature at a depth of 20 inches is 41 degrees F. It is dry in all parts of the moisture control section for at least 60 consecutive days between July 1 and October 15 and for at least 90 cumulative days during this period.
The A horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 or 3. Cracks one cm. wide typically extend to the surface of most pedons. It is moderately acid through strongly acid.
An AB or BA horizon occurs in some pedons. They have the same range in characteristics as the A and B horizons.
The Bw horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry and 4 or 5 moist, and chroma of 2 or 3. This horizon averages 60 to 75 percent clay. Cracks one cm. wide or wider extend through this horizon. Structure is typically angular or subangular blocky with common vertical pressure faces occurring on faces of peds. It is strongly through extremely acid.
The C horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry and 4 or 5 moist, and chroma of 2 through 4. This horizon averages 60 to 75 percent clay. Cracks one cm. wide or wider are common to 30 inches or more. Authigenic gypsum crystals occur in few to common masses and nests in some pedons. It is very strongly or extremely acid.
COMPETING SERIES: This is the Felix series. Felix soils are moderately well drained and are neutral through moderately alkaline in the Bw and C horizons.
GEOGRAPHIC SETTING: Bumbob soils are on alluvial fans, footslopes and toeslopes. Slopes are 0 to 10 percent. The soils formed in fine textured slope alluvium derived from acid shale. Elevations are 3,800 to 4,500 feet. The mean annual precipitation is 10 to 14 inches of which about half falls as snow or rain in April, May, and early June and less than one inch falling in each month of July, August, and September. The mean annual air temperature ranges from 45 to 51 degrees F. The frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackdraw and Paiges soils. Blackdraw soils lack a cambic horizon and vertical cracks one cm. wide or wider when dry. Paiges soils have an umbric epipedon and a paralithic contact between depths of 20 and 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: These soils are utilized for grazing by domestic livestock and as wildlife habitat. Native vegetation is mainly western wheatgrass, green needlegrass, silver sage, blue grama, and prickly pear.
DISTRIBUTION AND EXTENT: Eastern Wyoming. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Niobrara County, Wyoming; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - 0 to 3 inches (A)
2. Cambic horizon - 3 to 19 inches (Bw1,Bw2)
3. Ustertic subgroup - Aridic moisture regime bordering on Ustic. Cracks remain open in most years for 175 to 240 days and do not remain closed for 60 consecutive days or more from Dec. 21 to Mar. 21.
4. SIR - WY0780
5. LRR=G