Ecological site group description

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

Physiography

This ecological site is found on plateaus fan terraces, and valley floors, alluvial flats, dissected alluvial fans, alluvial fans and structural benches. The soil is deep to very deep to any plant root restricting layer. The soil surface texture ranges from very fine sandy loam to light sandy clay loam. Subsurface horizon textures are generally loam or clay loam, but range from sandy loam to clay. There is typically enough soil development to have accumlation of clays and/or carbonates (cabmic or argillic) at shallow depths within the soil profile. The soil surface and subsurface horizons may be slightly effervescent. Slopes are predominantly 0 to 15 percent, but occasionally reach 20 percent.


(1) Residuum - calcareous sandstone


(2) Alluvium - limestone and sandstone

Climate

Winter to summer moisture ratios range from 70:30 to 60:40. Late spring is usually the driest period, and early fall moisture can be sporadic. Summer rains fall from June through September; moisture originates in the Gulf of Mexico and creates convective, usually brief, intense thunderstorms. Cool season moisture from October through May tends to be frontal; it originates in the Pacific and the Gulf of California and falls in widespread storms with longer duration and lower intensity. Precipitation generally comes as snow from December through February. Accumulations above 12 inches are not common but can occur. Snow usually lasts for 3-4 days, but can persist much longer. Summer daytime temperatures are commonly 95 - 100 F and on occasion exceed 105 F. Winter air temperatures can regularly go below 10 F and have been recorded below - 20 F.

Soil features

Soils grouped into this ecological site are generally deep to very deep, but may be moderately deep to any plant root restricting layer. The soil surface texture ranges from very fine sandy loam to light sandy clay loam. Subsurface horizon textures are generally loam or clay loam, but range from sandy loam to clay. The soil surface may be slightly effervescent. Subsurface horizons range from slightly to strongly effervescent. Soil reaction is neutral to moderately alkaline (pH 7.0-8.4). Water erosion hazard is moderate to severe.

Vegetation dynamics

This site has a plant community made up primarily of mid and short grasses with a moderate amount of shrubs. In the original plant community there is a mixture of both cool season and warm season plants.

Plants most likely to invade on this site are big sagebrush, snakeweed, rabbit-brush, juniper and annuals.

Major Land Resource Area

MLRA 035X
Colorado Plateau

Subclasses

• R035XB226AZ–Sandstone/Shale Upland 6-10" p.z. Warm
• R035XB232AZ–Limestone/Sandstone Upland 6-10" p.z.
• R035XD415AZ–Shallow Loamy 7-11" p.z.
• R035XY122UT–Desert Shallow Loam (Shadscale)
• R035XY221UT–Semidesert Shallow Loam (Utah Juniper-Pinyon)
• R035XY226UT–Semidesert Shallow Loam (Black Sagebrush/Indian Ricegrass)

Correlated Map Unit Components

22340798, 22340809, 22340812, 22340835, 22340834, 22340840, 22340857, 22340860, 22340862

Stage

Provisional

Contributors

Curtis Talbot