LOCATION OLSON NV+CA OREstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid, shallow Haploxeralfic Argidurids
TYPICAL PEDON: Olson fine sandy loam, rangeland. (Colors are for dry soil unless otherwise noted.)
The surface has a 50 percent cover of fine (less tban 1 inch) andesite, basalt, and obsidium gravel.
A1--O to 1 inch, light brownish-gray (10YR 6/2) fine sandy loam with the surface 1/4 inch being light gray (10YR 7/2), very dark grayish b rown (10YR 3/2) when moist; massive; slightly hard, friable, nonsticky and slightly plastic; few root crowns only many very fine and fine vesicular pores; neutral (pH 6.6); abrupt, wavy boundary. 1/2 to 2 inches thick.
A2--1 to 4 inches, light-gray (10YR 7/2) fine sandy loam, very dark grayish brown (10YR 3/2) when moist; weak, thin platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; neutral (pH 6.6); clear, wavy boundary. 1 to 4 inches thick.
Bt1--4 to 9 inches, light brownish-gray (10YR 6/2) light sandy clay loam, dark grayish brown (10YR 4/2) when moist; weak, fine and medium, subangular blocky structure; slightly hard, very friable, slightly sticky and plastic; many very fine and fine roots; many very fine interstitial pores; common colloidal coatings and few thin clay films as bridges; neutral (pH 6.7), clear, wavy boundary. 1 to 6 inches thick.
Bt2--9 to 13 inches, light yellowish-brown (10YR 6/4) gravelly sandy clay loam, dark yellowish brown (10YR 4/4) when moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; common, very fine and fine, and few medium roots; few fine tubular pores; many thin clay films in pores and common thin on peds; neutral (pH o.8); abrupt, wavy boundary. 4 to 8 inches thick.
Bqm--13 to 15 inches, very pale-brown (10YR 7/3) indurated duripan with many yellowish brown (1OYR 5/4) opalescent coatings on continuous laminar caps, dark yellowish brown (10YR 4/4) when moist; strong, thin and thick, platy structure; extremely hard, extremely firm; few very fine and fine roots along plate tops and in fractures; many very fine interstitial pores; many thin and moderately thick silica bridges between sand grains; neutral (pH 7.0); abrupt, wavy boundary. 2 to 9 inches thick.
Bqkm--15 to 21 inches, variegated pale-brown (10YR 6/3) and very pale-brown (10YR 7/3) strongly cemented duripan, dark brown (10YR 4/3) and yellowish brown (10YR 5/6) when moist; massive; hard and very hard, firm and very firm; few very fine and fine roots; many very fine and fine interstitial pores; many thin and few moderately thick silica bridges between sand grains; common fine and medium white (10YR 8/1) lime coatings and few fine and medium yellowish-brown (10YR 5/4) opalescent coatings, slightly effervescent in matrix, and violently effervescent in lime coatings; strongly alkaline (pH 8.8); clear, smooth boundary. 5 to 12 inches thick.
2C--21 to 44 inches, light-gray (10YR 7/2) gravelly loamy sand with 1/4 to 1/2 inch thick very pale brown (10YR 7/3) and white (10YR 8/l) vertical lime seams on 4 to 6 inch centers from horizon above, grayish brown (10YR 5/2) and light brownish-gray (10YR 6/2) when moist; massive; hard, very friable, nonsticky and nonplastic; few very fine and fine roots- many very fine and fine interstitial pores; violently effervescent; strongly alkaline (pH 8.8).
TYPE LOCATION: Washoe County, Nevada; about 20 feet south of the Chester Lyons Spring Road; about 600 feet northwest of the SE corner of section 29, T.39N., R.22E.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to the indurated duripan range from 10 to 20 inches. Olson soils are usually dry during most years, mainly during the summer and early autumn, but are moist more than 1/4 of the time the soil temperature is more than 41 F. Mean annual soil temperature ranges from 45 to 47 F., and mean summer soil temperature ranges from 62 to 65 F. The solum ranges in pH from 6.5 to 7.0.
The A1 horizon has value of 6 or 7 dry, 3 or 4 moist, and chroma of 2 or 3. It has weak or moderate, thin or medium platy structure, or is massive. Transitional A3 or Bt horizons are in most pedons.
The Bt horizon has value of 6 or 7 dry, 4 or 5 moist, and chroma of 2, 3 or 4. It is commonly sandy clay loam, but is clay loam or loam in some pedons. Gravel content ranges up to 35 percent. The B2t horizon has weak fine or medium prismatic, weak or moderate very fine to medium subangular blocky structure, or is massive.
The duripan has value of 6, 7 or 8 dry, 4 or 5 moist, and chroma of 2, 3 or 4. Coatings in some pedons have chroma of 1 through 6. The duripan ranges from 6 to 26 inches thick, but the indurated part ranges from 2 to 9 inches thick. The upper part of the duripan is normally noncalcareous but ranges to slightly calcareous. pH values range from 7.0 where noncalcareous, to 8.8 where calcareous. The remainder of the profile is calcareous and ranges in pH from 8.O to 9.0. Unconformable very gravelly or gravelly, sandy or loamy materials underlie the duripans. These are weakly cemented in some pedons and range from hard to loose. Cementation decreases as depth increases.
COMPETING SERIES: These are the Bellavista, Cortez, Fertaline, Minu, Umil and Usave series. Bellavista soils have mean annual soil temperatures more than 47 F., and are calcareous and moderately alkaline throughout the solum. Cortez and Usave soils have sola 22 to 36 inches thick, clay B2t horizons, and lime in the lower part of the solum. Fertaline soils have 20- to 30-inch sola, abrupt AB boundaries, and columnar B2t horizons of clay texture. Minu soils are calcareous and moderately alkaline in the lower part of the solum, and have 1/8 to 1/4 inch silica-indurated laminae in a strongly cemented matrix. Umil soils have more than 15 percent exchangeable sodium in their B2t horizons, are calcareous throughout the profile, and are moderately alkaline to very strongly alkaline in the solum.
GEOGRAPHIC SETTING: Olson soils are on nearly level to strongly sloping dissected lacustrine terraces at elevations of 4,900 to 5,500 feet. They formed in lacustrine valley-fill materials derived mainly from tuffs and related basic volcanic rock sources. The climate is cool, semiarid, having mean annual precipitation of 8 to 10 inches. The mean annual temperature ranges from 43 to 45 F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Espil, Mascamp and Powley soils. Espil soils have mollic epipedons and clay Bt horizons. Mascamp soils have very cobbly and gravelly sandy clay loam B2t horizons and lithic contacts at depths of less than 20 inches. Powley soils have mollic epipedons and clay Bt horizons.
DRAINAGE AND PERMIABILITY: Well-drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used to provide livestock grazing. Big sagebrush and spiny hopsage dominate the vegetative aspect, but Indian ricegrass and squirreltail are important members.
DISTRIBUTION AND EXTENT: Northern Washoe County, Nevada. The soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Washoe County, Nevada, 1974.
REMARKS: These soils were formerly classified as Brown soils.
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 Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.