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

These ecological sites occur on toeslopes between cuestas, footslopes and alluvial cones of escarpments, and terraces and summits associated with cuestas, mesas, and structural benches. The soils formed in alluvium and residuum derived from Jurassic and Cretaceous sandstone and shale, Dakota sandstone, and Mancos shale. Slopes are 0 to 15 percent.

Climate

Winter 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 degrees F and on occasion exceed 105 degrees F. Winter air temperatures can regularly go below 10 degrees F and have been recorded below - 20 degrees F.

Soil features

Soils are moderately deep to very deep. Parent material is residuum from mudstone, sandstone, and shale. Surface textures are extremely cobbly very fine sandy loam to extremely cobbly sandy clay loam, and very fine sandy loam to sandy loam. Subsoils are very gravelly clay loam to clay, and fine sandy loam to sandy clay loam. Electrical Conductivity is 8 – 16 mmhos/cm. SAR is 5 - 30 dS/m. Wind erosion hazard is slight to severe; water erosion hazard is moderate. pH range is 7.4 - 9.0.

Vegetation dynamics

Please see associated ecological sites under subclasses to view state and transition models.

Major Land Resource Area

MLRA 035X
Colorado Plateau

Subclasses

• R035XB024NM–Saline Bottom 6-10"
• R035XB229AZ–Cobbly Slopes 6-10" p.z. Saline
• R035XB274AZ–Sandy Loam Upland 6-10" p.z. Saline
• R035XB276AZ–Siltstone Upland 6-10" p.z. Saline
• R035XC325AZ–Cobbly Slopes 10-14" p.z. Saline
• R035XC326AZ–Sandy Loam Upland 10-14" p.z. Saline

Correlated Map Unit Components

22999404

Stage

Provisional

Contributors

Curtis Talbot