LOCATION MAYFLOWER               MT

Established Series
Rev. AJC/TDL/EMM
05/2013

MAYFLOWER SERIES


The Mayflower series consists of moderately deep, well drained soils formed in residuum from sandstone, siltstone and shale. They are on hills, ridges, stream terraces, and mountain slopes. Slopes are 0 to 60 percent. The average annual precipitation is about 20 inches and the average annual temperature is about 38 degrees F.

TAXONOMIC CLASS: Fine, smectitic Pachic Argicryolls

TYPICAL PEDON: Mayflower loam, forested, on a 20 percent north-facing slope at 5,860 feet elevation. (Colors are for air dry soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed pine needles, grasses, forbs, and shrub leaf stems, roots and duff material. (0 to 3 inches thick)

A--1 to 4 inches; dark gray (10YR 4/1) loam, very dark gray (10YR 3/1) moist; moderate fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine and common medium and few coarse roots; many very fine, fine and medium and few coarse irregular pores; neutral (pH 7.0); clear smooth boundary. (3 to 10 inches thick)

Bt1--4 to 14 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium angular blocky structure; very hard, very firm, very sticky and very plastic; many very fine and common fine and medium and few coarse roots; common very fine, fine and medium and few coarse irregular pores; 25 percent distinct and faint clay films on vertical faces of peds and on surfaces of pores; neutral (pH 7.0); clear smooth boundary.

Bt2--14 to 25 inches; dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; common fine and coarse roots; common fine and few coarse irregular pores; 35 percent distinct and faint clay films on vertical faces of peds and on surfaces of pores; slightly alkaline (pH 7.4); clear smooth boundary. (Combined thickness of Bt horizons is 15 to 25 inches thick)

Cr--25 to 60 inches; light brownish gray (2.5Y 6/2) weakly and semi- consolidated shale and interbedded sandstone, grayish brown (2.5Y 5/2) moist; violently effervescent; strongly alkaline (pH 8.6); gradual smooth boundary.

TYPE LOCATION: Park County, Montana; 2400 feet east and 1400 feet north of the southwest corner of section 29 T4N R10E.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 36 to 44 degrees F.
Mean summer soil temperature - 38 to 46 degrees F.
Mollic epipedon thickness - 16 to 30 inches.
Depth to paralithic contact - 20 to 40 inches.
Rock fragments range from 0 to 15 but are commonly less than 5 percent.

A horizon
Hue: 10YR or 7.5YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 to 3, dry or moist
Texture: loam or silt loam
Clay content: 18 to 27 percent
Rock fragments: 0 to 15 percent total - 0 to 10 percent gravel, 0 to 10 percent cobbles
Reaction: pH 6.6 to 7.6

Bt horizons
Hue: 10YR, 5YR or 2.5YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 to 4, dry or moist
Texture: Clay loam, clay, silty clay or silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 15 percent total - 0 to 10 percent gravel, 0 to 10 percent cobbles
Sand content 15 to 40 percent with more than 15 percent fine sand or coarser
Reaction: pH 6.6 to 7.8

Btk horizon (when present)
Hue: 10YR, 5YR or 2.5YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 to 4, dry or moist
Texture: Clay loam, clay, silty clay or silty clay loam
Clay content: 35 to 45 percent
Rock fragments: 0 to 15 percent total - 0 to 10 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: 3 to 15 percent
Reaction: pH 7.4 to 8.4

COMPETING SERIES:
Bischoff (ID) - are very deep
Burnette (MT) - are very deep
Cochetopa (CO) - are very deep
Currycreek (MT) - are very deep
Faim (UT) - are very deep
Fulcher (CO) - are very deep
Grouseville (ID) - are very deep
Guero (CO) - are very deep
Leemorris (OR) - has a lithic contact at 20 to 40 inches
Lintim (CO) - are very deep
Mancos (CO) - has a lithic contact at 20 to 40 inches
Paulson (WY) - are very deep
Perinos (UT) - are very deep
Richens (UT) - has a lithic contact at 40 to 60 inches
Runlett (CO) - has a lithic contact at 20 to 40 inches
Skutum (UT) - has a paralithic contact at 40 to 60 inches
Winridge (ID) - has a lithic contact at 20 to 40 inches

GEOGRAPHIC SETTING:
Landform - They are on hills, ridges, stream terraces, and mountain slopes.
Elevation - 4500 to 8,000 feet.
Slope - 0 to 60 percent.
Parent material - residuum from calcareous sandstone, siltstone and shale.
Mean annual precipitation - 15 to 25 inches with peak periods of precipitation occurring during the spring and early summer months.
Mean annual air temperature - 34 to 42 degrees F.
Mean average summer air temperature - 42 degrees F.
Frost free period - 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Doby and Adel series. Doby soils are shallow and smectitic and are on sedimentary plains and hills. Adel soils are fine-loamy and pachic and are on alluvial fans, stream terraces, hills, drainageways, and swales.

DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; slow permeability.

USE AND VEGETATION: These soils are used principally as native pastureland, rangeland and understory grazing. Native pasture vegetation is Richardsons needlegrass, mountain brome, slender and bearded wheatgrass, Idaho fescue, bluebunch wheatgrass, big sagebrush, and lupine. Forested areas are dominated by Douglas-fir, service berry and common snowberry. Aspen occupy small areas.

DISTRIBUTION AND EXTENT: The soils of this series are of moderate extent in central and south central Montana and west central Wyoming. MLRA 43B and 44B.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Mesa County (Lower Colorado Area), Colorado, 1970.

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

Particle-size control section - the zone from 4 to 24 inches (Bt1, Bt2).

Mollic epipedon - 1 to 25 inches (A, Bt1, and Bt2).

Argillic horizon - 4 to 25 inches (Bt1, and Bt2).

Paralithic contact - 25 inches (Cr).

Mayflower soils have a cryic temperature regime and an ustic moisture regime.

This description reflects a change in the type location from Mesa County, Colorado to Park County, Montana. The Mayflower series is currently not used in Colorado.


National Cooperative Soil Survey
U.S.A.