LOCATION CROPPER NVEstablished Series
The Cropper series consists of shallow, well drained soils that formed in residuum and colluvium derived from andesite, quartzite, conglomerate, and rhyolite. Cropper soils are on mountains and hills. Slopes are 8 to 75 percent. The mean annual precipitation is about 14 inches and the mean annual temperature is about 42 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Argixerolls
TYPICAL PEDON: Cropper very cobbly loam, extremely stony--forestland. The soil surface is partially covered with 20 percent pebbles, 15 percent cobbles, and 5 percent stones.
A--0 to 4 inches; dark grayish brown (10YR 4/2) very cobbly loam, very dark brown (10YR 2/2) moist; moderate very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine through medium roots; common very fine tubular and interstitial pores; 20 percent pebbles, 15 percent cobbles, and 5 percent stones; neutral (pH 7.2); abrupt smooth boundary. (2 to 5 inches thick)
Bt1--4 to 7 inches; dark grayish brown (10YR 4/2) extremely gravelly sandy clay loam, very dark grayish brown (10YR 3/2) moist; moderate very fine and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine through coarse roots; common very fine and fine tubular pores; few faint clay films on faces of peds; 50 percent pebbles and 10 percent cobbles; neutral (pH 7.2); clear smooth boundary. (0 to 5 inches thick)
Bt2--7 to 16 inches; dark yellowish brown (10YR 4/4) extremely gravelly sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; common very fine through coarse roots; common very fine and fine tubular pores; many distinct clay films on faces of peds; 60 percent pebbles and 10 percent cobbles; slightly alkaline (pH 7.4); abrupt wavy boundary. (6 to 10 inches thick)
R--16 inches; hard andesite.
TYPE LOCATION: White Pine County, Nevada; about 0.75 miles east of Quaky Spring; about 200 feet south and 1,000 feet west of the northeast corner of section 36, T. 13 N. R. 63 E.; USGS White Rock Creek 7.5 minute topographic quadrangle; 38 degrees 57 minutes 6 seconds north latitude and 114 degrees 50 minutes 21 seconds west longitude, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in winter and spring, intermittently moist for 10 to 20 days cumulative between July and October due to summer convection storms. Aridic soil moisture regime that borders on xeric.
Mean annual soil temperature - 44 to 47 degrees.
Mollic epipedon thickness - 7 to 10 inches, includes the Bt1 horizon in some pedons.
Depth to bedrock - 14 to 20 inches to a lithic contact.
Reaction - Neutral or slightly alkaline.
Control section - Clay content: Averages 27 to 35 percent.
Rock fragments: 60 to 75 percent, by average, mainly pebbles.
A horizon - Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 1 through 3, dry or moist.
Organic matter content: 1 to 4 percent.
Bt horizons - Hue: 10YR or 7.5YR.
Value: 3 through 5 dry, 2 through 4 moist.
Chroma: 2 through 4 moist, chroma of 4 is typically in the Bt2 horizon.
Structure: Moderate or strong, very fine to medium subangular blocky or angular blocky.
Texture: Extremely gravelly sandy clay loam or extremely gravelly clay loam.
Organic matter content: 1 or 2 percent.
Consistence: Soft to hard, dry; very friable to firm, moist; slightly sticky or moderately sticky, slightly plastic or moderately plastic, wet.
Other features: In some pedons thin subhorizons overlying the bedrock have textures of sandy clay with 35 to 50 percent clay.
Clay films: Few to many, faint or distinct.
COMPETING SERIES: These are the
Bellenmine,
Celeridge,
Cleavage,
Cleavmor,
Gabica,
Gaciba,
Genoa,
Gerdog,
Gidwin,
Grosschat,
Hawkridge,
Hutchley,
Loope,
Mascamp,
Melling,
Pernog,
Pernty,
Rozara,
Shalcleav,
Shalper,
Slatter,
Tractuff, and
Tweener series.
Bellenmine soils are slightly acid or neutral and have more than 40 percent sand coarser than very fine sand in the argillic horizons. Celeridge, Cleavage, Cleavmor, Gabica, Gaciba, Genoa, Gerdog, Gidwin, Hawkridge, Hutchley, Loope, Mascamp, Pernog, Pernty, Rozara, Shalcleav, Shalper, Slatter, and Tweener soils are not moist for 10 to 20 days between July and October due to convection storms. Cleavage soils have mollic epipedons that do not include the argillic horizons. Celeridge, Gabica, Hawkridge, Loope, Melling, soils have a Xeric soil moisture regime. Cleavmor soils have identifiable secondary calcium carbonates in the argillic horizons.. Gaciba soils have 16 to 24 percent clay and 35 to 60 percent rock fragments in the particle-size control section. Gidwin soils have mollic epipedons 14 to 20 inches thick and 18 to 24 percent clay in the particle-size control section. Grosschat soils have 18 to 25 percent clay in the particle-size control section. Hutchley soils have mollic epipedons 10 to 20 inches thick. Mascamp soils are dominated by cobbles and stones in the particle-size control section and are influenced by volcanic ash. Pernog and Pernty soils have 35 to 50 percent rock fragments in the particle-size control section. Rozara soils have 14 to 18 percent clay in the particle-size control section and are 10 to 14 inches to bedrock. Shalcleav, Shalper, Slatter, and Tweener soils are less than 14 inches to bedrock. Tractuff soils have 18 to 27 percent clay in the particle-size control section and have subhorizons of the argillic horizon with identifiable secondary carbonates.
GEOGRAPHIC SETTING: Cropper soils are on mountains and hills. These soils formed in residuum and colluvium derived from andesite, quartzite, conglomerate, and rhyolite. Slopes are 8 to 75 percent. Elevations range from 6,200 to 9,200 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 12 to 14 inches, mean annual temperature is 41 to 45 degrees F., and the frost-free period is 80 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Pioche and Segura soils. Pioche and Segura soils are clayey-skeletal and loamy respectively, very shallow and shallow to lithic contacts, and have mollic epipedons and argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderately slow permeability.
USE AND VEGETATION: Cropper soils are used for wood production and wildlife habitat. The present vegetation is mainly a forest canopy of singleleaf pinyon and curlleaf mountain mahogany with an understory of mountain big sagebrush, Indian ricegrass, and pine bluegrass.
DISTRIBUTION AND EXTENT: Central Nevada. These soils are extensive with about 103,000 acres of the series mapped to date. MLRAs 28A, 28B and 29.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: White Pine County (Western Part), Nevada, 1990.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 7 inches (A and Bt1 horizons).
Argillic horizon - The zone from 4 to 16 inches (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 16 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 4 to 16 inches (Bt1 and Bt2 horizons).