LOCATION PENINSULA CO
Established Series
Rev. GB/JPP
01/2023
PENINSULA SERIES
The Peninsula series consists of very deep, well drained, moderately slowly permeable soils on high valley benches or terraces. These soils formed in alluvium and colluvium from mixed sources, mainly shale, loess, and volcanic material. Slopes range from 3 to 12 percent. Mean annual precipitation is about 14 inches, and the mean annual temperature is about 44 degrees F.
TAXONOMIC CLASS: Fine, smectitic, frigid Calcidic Argiustolls
TYPICAL PEDON: Peninsula loam - on 3 percent north-facing convex slope under grass hay at an elevation of 6,160 feet. (Colors are for dry soil unless otherwise noted)
Ap--0 to 4 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine to few medium roots; many very fine and few fine interstitial pores; neutral (pH 7.2); clear wavy boundary. (4 to 10 inches thick)
Bt1--4 to 10 inches; reddish brown (5YR 4/3) clay loam, dark reddish brown (5YR 3/3) moist; moderate fine subangular blocky structure parting to strong fine subangular blocky; hard, friable, sticky and plastic; many very fine, common fine, and few medium roots; many very fine and few fine interstitial pores; common distinct clay films on ped faces, many distinct clay films line pores; slightly alkaline (pH 7.4); clear wavy boundary. (5 to 14 inches thick)
Bt2--10 to 19 inches; reddish brown (5YR 5/4) clay loam, reddish brown (5YR 4/4) moist; moderate medium prismatic structure parting to strong coarse angular blocky; very hard, firm, sticky and plastic; common very fine roots; common very fine vertical tubular pores; many prominent clay films on faces of peds and many prominent clay films line pores; slightly alkaline (pH 7.4); clear wavy boundary. (5 to 14 inches thick)
Btk--19 to 28 inches; brown (7.5YR 5/4) clay loam, strong brown (7.5YR 4/6) moist with fine common distinct pinkish white (7.5YR 8/2) flecks of lime; moderate coarse subangular blocky structure parting to strong medium blocky; common very fine roots; common very fine vertical tubular pores; very hard, friable, sticky and plastic; few distinct clay films on faces of peds; 5 percent cobble; common fine and medium distinct specks and spots of lime; 6 percent calcium carbonate equivalent; strongly effervescent, moderately alkaline (pH 8.0); gradual wavy boundary. (5 to 10 inches thick)
Bk1--28 to 40 inches; pinkish white (7.5YR 8/2) loam, light brown (7.5YR 6/4) moist; massive; hard, friable, slightly sticky and slightly plastic; few roots; common very fine random pores; 5 percent cobbles; 30 percent calcium carbonate equivalent; violently effervescent, moderately alkaline (pH 8.2); gradual wavy boundary. (4 to 20 inches thick)
Bk2--40 to 53 inches; white (10YR 8/2) loam, very pale brown (10YR 7/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few roots, few very fine random pores; 33 percent calcium carbonate equivalent; violently effervescent, moderately alkaline (pH 8.2); gradual wavy boundary. (0 to 15 inches thick)
Bk3--53 to 62 inches; very pale brown (10YR 7/3) loam, with white (10YR 8/2) coatings, streaks, and spots, yellowish brown (10YR 5/4) moist; massive; slightly hard, very friable, nonsticky and nonplastic; very few roots, common very fine random pores; common medium rounded lime concretions; 9 percent calcium carbonate equivalent; strongly effervescent in matrix and violently effervescent in limy masses and coatings; moderately alkaline (pH 8.4).
TYPE LOCATION: Mesa County, Colorado, about one-half mile south of Collbran; 2,040 feet north and 1,940 feet east of the southwest corner of Sec. 35, T. 9 S., R. 95 W. U.S.G.S. Collbran quad.; Lat. 39 degrees, 13 minutes, 54 seconds N., and Long. 107 degrees, 59 minutes, 17 seconds W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 43 to 46 degrees F. The mollic epipedon is 7 to 16 inches thick and extends into the Bt2 horizon in some pedons. Epipedons which are less than 10 inches thick extend to at least one-third of the depth to the calcic horizon. Depth to the calcic horizon ranges from 16 to 33 inches. Calcium carbonate equivalent ranges from 20 to 60 percent in individual horizons. Rock fragments range from 0 to 20 percent in the solum and Ck or C horizons, if present. Fragments are mostly basalt and range in size from pebble to stone.
The A horizon has hue of 10YR or 7.5R, value of 4 or 5 dry and 2 or 3 moist, and chroma of 2 or 3. Reaction is neutral or slightly alkaline.
The Bt horizons have hue of 7.5YR or 5YR and some pedons have hue of 10YR in the upper part. They have value of 4 through 6 dry, and 3 through 5 moist, and chroma of 4 through 6. The upper part of some pedons have chroma of 3. Texture is clay loam or silty clay loam, with clay content between 35 and 40 percent. Reaction is neutral or slightly alkaline.
The Btk horizon has hue of 7.5YR or 5YR, value of 4 through 6 dry and 3 through 5 moist, and chroma of 4 through 6. Texture is clay loam or silty clay loam with between 32 and 38 percent clay. Reaction is slightly alkaline or moderately alkaline.
The Bk horizons have hue of 10YR or 7.5YR, value of 7 or 8 dry, and 6 or 7 moist, and chroma of 2 through 4. The fine-earth fraction is loam, silt loam, clay loam, or silty clay loam, with clay content between 24 and 32 percent. Reaction is moderately alkaline or strongly alkaline.
The C horizon, if present, has hue of 2.5Y or 10YR. Textures range from silty clay loam to loam, with between 24 and 32 percent clay content. Rock fragments range from 0 to 20 percent basaltic pebbles, cobbles, and stone.
COMPETING SERIES: These are the
Absarokee (MT),
Acree (CO),
Bearpaw (MT),
Brolliar (AZ),
Danvers (MT),
Delson (CO),
Herm (CO),
Morapos (CO),
Nortez (CO),
Pramiss (CO),
Regent (ND),
Reget (WY),
Ricot (CO),
Wyola (MT),
Tamaneen (MT),
Tomasaki (UT),
Tukuhnik (UT), and
Work (MT) series.
Absarokee,
Brolliar,
Nortez,
Pramiss,
Regent, and
Reget soils have a paralithic or lithic contact at depth of 20 to 40 inches.
Delson,
Herm, and
Tomasaki soils are noncalcareous throughout.
Acree,
Bearpaw,
Morapos,
Ricot,
Wyola,
Tamaneen,
Tukuhnik, and
Work soils do not have calcic horizons.
In addition, the
Bearpaw,
Wyola, and
Tamaneen soils receive most of their precipitation during the spring and early summer.
Danvers soils have calcic horizons, and receive most of their moisture in spring and early summer, and have mean annual soil temperatures of 42 to 45 degrees F.
GEOGRAPHIC SETTING: Peninsula soils are on high valley benches or terraces. Relief is variable and slopes range from 3 to 12 percent. The soils formed in alluvial material from mixed shale, loessial, and volcanic sources. Elevation ranges from 6,200 to 6,800 feet. The mean annual temperature ranges from 42 to 45 degrees F., and the mean annual precipitation ranges from 12 to 19 inches, and is distributed throughout the year, but with a low in June, and with about 30 percent falling in the months of August through October. The frost-free period is 85 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Clapper,
Empedrado,
Fughes, and
Hesperus soils. Clapper soils lack both a mollic epipedon and an argillic horizon. They occupy steeper and generally sun-facing slopes at somewhat lower elevation and have a mesic soil temperature regime. Empedrado, Fughes, Hesperus, and
Zoltay soils are at somewhat higher elevations where they receive 16 to 20 or more inches precipitation. None of these soils have calcic horizons and, the Empedrado soils have mollic epipedons more than 16 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: Most of the areas of the Peninsula soils are cultivated and all cultivated acreage is irrigated. Orchard grass, Kentucky bluegrass, clover, alfalfa, and small grain are the principal plants.
DISTRIBUTION AND EXTENT: Peninsula soils are not extensive, with about 6,000 acres mapped in western Mesa County, Colorado.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Mesa County (Douglas-Plateau Soil Survey Area), Colorado, 1988.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Mollic epipedon - the zone from the surface to a depth of approximately 10 inches (Ap, Bt1 horizons);
Argillic horizon - the zone from approximately 4 to 28 inches (Bt1, Bt2, and Btk horizons);
Calcic feature - the zone from approximately 28 to 53 inches (Bk1, Bk2 horizons;
Borolls feature - inferred from susceptibility to frost in any month except July, inability to grow corn for grain, and certainty of only two cuttings of alfalfa. Nearest climatic station, at the lower elevation range of the series, shows a mean annual air temperature of 45.6 degrees F. Most of the Peninsula soil is north-sloping.
The other diagnostically similar series do not have the June precipitation minima, and therefore do not behave similarly under use and management for rangeland or for irrigation requirements.
Last updated by the state 6/95.
National Cooperative Soil Survey
U.S.A.