LOCATION LOMAKI                  AZ

Established Series
Rev. DRT/RCH/PDC/WWJ
07/2023

LOMAKI SERIES

The Lomaki series consists of very deep, somewhat excessively drained soils that formed in alluvium from pyroclastics and cinders. Lomaki soils are on fan terraces or cinder cones and have slopes of 0 to 65 percent. The mean annual precipitation is about 12 inches and the mean annual air temperature is about 52 degrees F.

TAXONOMIC CLASS: Ashy-skeletal over fragmental or cindery, glassy, mesic Sodic Haplocambids

TYPICAL PEDON: Lomaki extremely gravelly loam - rangeland. (Colors are for dry soil unless otherwise noted.) 85 percent surface cover of 2 mm to 1 cm diameter cinders.

A1--0 to 3 inches; brown (10YR 5/3) extremely gravelly loam, dark brown (7.5YR 3/2) moist; moderate thick platy structure; soft, very friable, slightly sticky and nonplastic; many fine, medium and coarse roots; many very fine and fine vesicular pores; 75 percent cinders; moderately alkaline (pH 8.0); clear smooth boundary. (1 to 5 inches thick)

A2--3 to 8 inches; grayish brown (10YR 5/2) very gravelly loam, dark brown (7.5YR 3/2) moist; weak fine and medium subangular blocky and granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; few very fine and fine tubular and common fine irregular pores; 40 percent cinders; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 10 inches thick)

Bk1--8 to 14 inches; light yellowish brown (10YR 6/4) very gravelly loam, dark yellowish brown (10YR 3/4) moist; weak very fine and fine granular structure; soft, very friable, slightly sticky and nonplastic; many fine roots; few very fine and fine tubular and common fine irregular pores; strongly effervescent; 50 percent calcium carbonate coated cinders; strongly alkaline (pH 8.6); clear wavy boundary. (6 to 10 inches thick)

Bk2--14 to 24 inches; pale brown (10YR 6/3) extremely gravelly loam, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; common very fine and fine tubular pores; violently effervescent; 60 percent calcium carbonate coated cinders; very strongly alkaline (pH 9.2); clear wavy boundary. (5 to 10 inches thick)

2Ck--24 to 60 inches; black (10YR 2/1) cinders, dark gray (10YR 4/1) moist; loose; cinders in upper 15 to 20 inches have coatings of calcium carbonate, decreasing with depth; violently effervescent; very strongly alkaline (pH 9.2).

TYPE LOCATION: Coconino County, Arizona; 2,100 feet west and 2,100 feet south of the northeast corner of section 30, T.26 N., R.8 E.

RANGE IN CHARACTERISTICS:

Soil Moisture: Intermittently moist in some part of the soil moisture control section during July-September and December-February. Driest during May and June. Ustic aridic soil moisture regime.

Rock Fragments: Averages 45 to 75 percent cinders by volume; greater than 60 percent by weight

Depth to cinders: 20 to 40 inches

Organic matter: 1 to 2 percent above the cinders

A horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
Reaction: Neutral to moderately alkaline

B horizon
Hue: 5YR, 7.5YR, 10YR
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 2 through 4, dry or moist
Texture: Loam, clay loam (10 to 25 percent clay)
Reaction: Neutral to very strongly alkaline

C horizon
Hue: N, 5YR, 7.5YR, 10YR
Value: 2 to 7 dry, 1 to 5 moist
Chroma: 1, 2 or 6 dry, 2, 3, or 4 moist
Cinders: Averages 95 to 100 percent by volume

COMPETING SERIES: This is the Wukoki (AZ) series. Wukoki soils have cinders at depths less than 20 inches.

GEOGRAPHIC SETTING: Lomaki soils are on fan terraces and cinder cones and have slopes of 0 to 65 percent. These soils formed in material from pyroclastics and cinders. Elevations range from 4,800 to 6,500 feet. The mean annual precipitation ranges from 10 to 14 inches. The mean annual air temperature is 48 to 56 degrees F. The frost-free period is 130 to 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aut, Tuweep, Nalaki and Wupatki soils and the competing Wukoki soil. Aut soils have bedrock at depths of 20 to 40 inches. Tuweep soils have a fine-loamy control section. Nalaki soils have a duripan at depths of 20 to 40 inches. Wupatki soils have a duripan at depths less than 20 inches.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderately rapid permeability.

USE AND VEGETATION: Lomaki soils are used for livestock grazing and wildlife habitat. Vegetation is black grama, blue grama, galleta, sideoats grama, dropseed, winterfat, and rabbitbrush.

DISTRIBUTION AND EXTENT: Northern Arizona. This series is of moderate extent. MLRA 35 & 39.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Coconino County; Soil survey of Coconino County Area, AZ, Central Part; 1980.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - The zone from 0 to 8 inches (A1, A2 horizons)

Cambic horizon - The zone from 8 to 24 inches (Bk1, Bk2 horizons)

Cinder deposit at a depth of 24 inches

Classified according to Soil Taxonomy Second Edition, 1999.

ADDITIONAL DATA: NSSL sample S75AZ-005-012

---

National Cooperative Soil Survey
U.S.A.