Ecological site group DX035X01IESG08
Little Colorado River Basin-Loamy soils, run in moisture
Last updated: 10/12/2022
Accessed: 05/02/2024
Ecological site group description
Key Characteristics
- Little Colorado River Basin
- Loamy
- Receive extra run-in moisture
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 site occurs in the bottom position of level to gently sloping flood plains, valley floors, stream terraces and drainageways. It benefits significantly from run-in moisture from adjacent areas. Slopes are mainly less than 5 percent.
Climate
50-60% of moisture falls as rain Jul-Sep and is the most effective moisture for plant growth. The remaining moisture comes as snow during the winter.
Mean temperature for the hottest month (Jul) is 72 F; for the coldest month (Jan) is 32 F. Extreme temperatures of 105 F and -28F have been recorded. Long periods with little or no effective moisture are relatively common.
Cool season plants begin growth in early spring and mature in early summer. Warm season plants take advantage of summer rains and are growing and nutritious Jul-Sep.
Soil features
Soils are deep to very deep (60+ inches), well-drained and have no plant root restricting layers. The surface textures are typically fine sandy loam to sandy clay loam. The subsurface horizons have textures of sandy loam, gravelly sandy loam, fine sandy loam, loam, gravelly loam, sandy clay loam, silty clay loam, or clay loam. Soluble salts are low and the soil reaction ranges from neutral to moderately alkaline (pH 6.6 to 8.4). The soil can absorb and hold all the moisture the climate supplies.
Vegetation dynamics
The plant communities found on an ecological site are naturally variable. Composition and production will vary with yearly conditions, location, aspect, and the natural variability of the soils. The reference community represents the natural potential plant communities found on relict or relatively undisturbed sites. Other plant communities described here represent plant communities that are known to occur when the site is disturbed by factors such as grazing, fire, or drought.
The reference state and the reference (climax) plant community has been determined by study of relict areas or areas protected from excessive disturbances. Trends in plant communities going from unmanaged grazed areas to managed grazed areas, seasonal use pastures and historical accounts have also been used.
This reference state is characterized as a native mixed grassland dominated by western wheatgrass and blue grama.
This plant community is made up primarily of mid and short grasses with a relatively small percentage of forbs and shrubs. Western wheatgrass and blue grama are the dominant grasses with fourwing saltbush and winterfat as the common shrubs.
Plant species most likely to invade or increase on this site when it deteriorates are rabbitbrush, broom snakeweed, annuals, cacti, and wooly groundsel. Unmanaged grazing during the winter and spring periods will decrease the cool season grasses, which are replaced by warm season, lower forage value grasses and shrubs.
As disturbances increase, shrub species increase. This creates a mixed grassland/shrub community with galleta and blue grama as the dominant grasses. There may be scattered non-native species, but they do not alter the function and processes of this phase.
Major Land Resource Area
MLRA 035X
Colorado Plateau
Subclasses
Correlated Map Unit Components
22341070, 22341128, 22341127, 22341134, 22341169, 22341179, 22341646, 22353891, 22353901, 22353906, 22353931, 22353934, 22353944, 22353961, 22353967, 22353997, 22353440, 22353442, 22396687, 22396781, 22396710, 22396681, 22396720, 22396742, 22396743, 22396836, 22484773, 22484781
Stage
Provisional
Contributors
Curtis Talbot
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