Natural Resources
Conservation Service
Ecological site DX035X01I112
Loamy Wash 10-14" p.z.
Last updated: 5/02/2024
Accessed: 11/21/2024
General information
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.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
MLRA notes
Major Land Resource Area (MLRA): 035X–Colorado Plateau
This ecological site occurs in Common Resource Area 35.1 - the Colorado Plateau Mixed Grass Plains
Elevations range from 4800 to 6300 feet and precipitation averages 10 to 14 inches per year. Vegetation includes Stipa species, Indian ricegrass, galleta, and blue grama, fourwing saltbush, winterfat, and cliffrose. The soil temperature regime is mesic and the soil moisture regime is ustic aridic. This unit occurs within the Colorado Plateau Physiographic Province and is characterized by a sequence of flat to gently dipping sedimentary rocks eroded into plateaus, valleys and deep canyons. Sedimentary rock classes dominate the plateau with volcanic fields occurring for the most part near its margin.
Ecological site concept
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 always less than 5 percent.
Soils are very deep and well-drained. 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).
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Atriplex canescens |
| Herbaceous |
(1) Pascopyrum smithii |
Legacy ID
R035XA112AZ
Physiographic features
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 always less than 5 percent.
Table 2. Representative physiographic features
| Landforms |
(1)
Flood plain
(2) Stream terrace (3) Valley floor |
|---|---|
| Flooding duration | Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours) |
| Flooding frequency | Rare to occasional |
| Elevation | 4,800 – 6,300 ft |
| Slope | 5% |
| Aspect | Aspect is not a significant factor |
Climatic features
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.
Table 3. Representative climatic features
| Frost-free period (average) | 160 days |
|---|---|
| Freeze-free period (average) | 180 days |
| Precipitation total (average) | 13 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
The soil moisture on this ecological site comes from precipitation and run-on moisture following storm events. The site may also benefit from lateral underground water movement from the streambed for periods of time after the surface water has drained off. This additional moisture allows this site to produce significantly more vegetation than upland sites that depend entirely on rainfall.
Soil features
Soils are 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.
Soil survey map unit components that have bee correlated to this ecological site include:
SSA Coconino County Central (631) Lynx MU's 55, 4, 29, 32; Paymaster MU 29;
SSA Navajo County Central (633) Radnik MU 49, Medisaprists MU 51, Manzano MU 36, Ustic torrifluvents MU 51, Escavada family MU 19;
SSA Apache County Central (635) Loamy Alluvial Land MU LO, Tours MU's TH, TL;
SSA Yavapai County Western (637) Rune MU's PnB, Rt; Cordes varient MU MsB; Tours MU To;
SSA Mohave County Central (697) Truxton MU 148;
SSA-715 Ft. Defiance Area AZ/NM MU's 104 San Mateo & Radnik.
Table 4. Representative soil features
| Parent material |
(1)
Alluvium
–
shale
|
|---|---|
| Surface texture |
(1) Fine sandy loam (2) Gravelly loam (3) Sandy clay loam |
| Family particle size |
(1) Loamy |
| Drainage class | Moderately well drained to well drained |
| Permeability class | Moderately slow to moderately rapid |
| Soil depth | 40 – 60 in |
| Surface fragment cover <=3" | 15% |
| Available water capacity (0-40in) |
6 – 13 in |
| Electrical conductivity (0-40in) |
2 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
5 |
| Soil reaction (1:1 water) (0-40in) |
6.6 – 8.4 |
Ecological 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 historical climax plant 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.
Production data provided in this site description is standardized to air-dry weight at the end of the summer growing season. The plant communities described in this site description are based on near normal rainfall years.
NRCS uses a Similarity Index to compare existing plant communities to the plant communities described here. Similarity Index is determined by comparing the production and composition of a plant community to the production and composition of a plant community described in this site description. To determine Similarity Index, compare the production (air-dry weight) of each species to that shown in the plant community description. For each species, count no more than the maximum amount shown for the species, and for each group, count no more than the maximum shown for the group. Divide the resulting total by the total normal year production shown in the plant community description. If rainfall has been significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
The State and Transition model shows the most common occurring plant communities likely to be encountered on this ecological site. This model may not show every possible plant community, but only those that are most prevalent and observed through field inventory. As more data is collected these plant communities may be revised, removed, and some added to reflect the ecological dynamics of this site.
State and transition model
Figure 4. State and Transition Model – R035XA112AZ
More interactive model formats are also available.
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More interactive model formats are also available.
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Click on state and transition labels to scroll to the respective text
Ecosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Reference State
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.
Community 1.1
Reference Plant Community: Mixed Grassland with Few Shrubs-Forbs
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.
Figure 5. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
| Plant type | Low (lb/acre) |
Representative value (lb/acre) |
High (lb/acre) |
|---|---|---|---|
| Grass/Grasslike | 675 | 1125 | 1500 |
| Shrub/Vine | 200 | 330 | 460 |
| Forb | 25 | 45 | 65 |
| Total | 900 | 1500 | 2025 |
Table 6. Ground cover
| Tree foliar cover | 0% |
|---|---|
| Shrub/vine/liana foliar cover | 0% |
| Grass/grasslike foliar cover | 0% |
| Forb foliar cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 15-40% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 10-25% |
Table 7. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | 0-2% | 1-5% | 1-2% |
| >0.5 <= 1 | – | 1-3% | 5-20% | 1-2% |
| >1 <= 2 | – | 1-5% | 1-5% | – |
| >2 <= 4.5 | – | – | – | – |
| >4.5 <= 13 | – | – | – | – |
| >13 <= 40 | – | – | – | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
Figure 6. Plant community growth curve (percent production by month). AZ5102, 35.1 10-14" p.z. blue grama. Growth occurs mostly in summer and early fall during the rainy season..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 0 | 5 | 5 | 15 | 30 | 30 | 15 | 0 | 0 | 0 |
Figure 7. Plant community growth curve (percent production by month). AZ5103, 35.1 10-14" p.z. sideoats grama. Most growth occurs in summer and early fall during the rainy season..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 0 | 5 | 10 | 20 | 30 | 20 | 10 | 5 | 0 | 0 |
Figure 8. Plant community growth curve (percent production by month). AZ5213, 35.1 10-14" p.z. winterfat. Growth begins in the spring and continues through the summer. Seed stalk extension and seed set occurs in summer..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 5 | 15 | 25 | 20 | 10 | 15 | 10 | 0 | 0 | 0 |
Community 1.2
Mixed Grassland and Shrub Community
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.
Pathway 1.2
Community 1.1 to 1.2
Unmanaged grazing, especially during spring/fall months. Introduction of non-native annuals. Unmanaged grazing can be described here as: Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
State 2
Native/Non-native State
This state is characterized by a decline in the site's ability to benefit from run-in moisture and/or flooding events. Active channels and gullies have changed the sites hydrologic function. Non-native species may occur along channels and drainageways, especially woody species such as tamarisk and Russian olive.
Community 2.1
Mixed Grassland and Shrub Community with Non-native Species
This site has increased shrub species, such as broom snakeweed, Greene's rabbitbrush, rubber rabbitbrush and whipple cholla and a decrease in perennial grasses. Non-native annuals, shrubs and/or trees have composition that affects the biotic integrity and hydrologic function of the site.
Transition T1A
State 1 to 2
Drought, unmanaged grazing, establishment and invasion of native and non-native species. Unmanaged grazing can be described here as: Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
Restoration pathway R2A
State 2 to 1
Managed grazing, woody species management/weed control, reseeding.
Conservation practices
| Brush Management | |
|---|---|
| Range Planting | |
| Prescribed Grazing | |
| Herbaceous Weed Control |
Additional community tables
Table 8. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | Dominant Grasses | 675–1200 | ||||
| western wheatgrass | PASM | Pascopyrum smithii | 350–700 | – | ||
| blue grama | BOGR2 | Bouteloua gracilis | 200–400 | – | ||
| spike muhly | MUWR | Muhlenbergia wrightii | 75–150 | – | ||
| 2 | Common Grasses | 75–225 | ||||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 25–95 | – | ||
| vine mesquite | PAOB | Panicum obtusum | 25–95 | – | ||
| James' galleta | PLJA | Pleuraphis jamesii | 25–95 | – | ||
| little bluestem | SCSC | Schizachyrium scoparium | 5–55 | – | ||
| sideoats grama | BOCU | Bouteloua curtipendula | 5–55 | – | ||
| 3 | Other grasses | 0–75 | ||||
| tumblegrass | SCPA | Schedonnardus paniculatus | 0–30 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–30 | – | ||
| mesa dropseed | SPFL2 | Sporobolus flexuosus | 0–15 | – | ||
| spike dropseed | SPCO4 | Sporobolus contractus | 0–15 | – | ||
| Grass, annual | 2GA | Grass, annual | 0–15 | – | ||
| Grass, perennial | 2GP | Grass, perennial | 0–15 | – | ||
| mat muhly | MURI | Muhlenbergia richardsonis | 0–15 | – | ||
| ring muhly | MUTO2 | Muhlenbergia torreyi | 0–15 | – | ||
|
Forb
|
||||||
| 4 | Forbs | 25–65 | ||||
| Forb, perennial | 2FP | Forb, perennial | 0–20 | – | ||
| globemallow | SPHAE | Sphaeralcea | 0–15 | – | ||
| common sunflower | HEAN3 | Helianthus annuus | 0–15 | – | ||
| western aster | SYAS3 | Symphyotrichum ascendens | 0–10 | – | ||
| Forb, annual | 2FA | Forb, annual | 0–10 | – | ||
| rose heath | CHER2 | Chaetopappa ericoides | 0–5 | – | ||
| western tansymustard | DEPI | Descurainia pinnata | 0–5 | – | ||
| whitestem blazingstar | MEAL6 | Mentzelia albicaulis | 0–5 | – | ||
| woolly plantain | PLPA2 | Plantago patagonica | 0–5 | – | ||
| little hogweed | POOL | Portulaca oleracea | 0–5 | – | ||
|
Shrub/Vine
|
||||||
| 5 | Dominant shrubs | 150–300 | ||||
| fourwing saltbush | ATCA2 | Atriplex canescens | 100–250 | – | ||
| winterfat | KRLA2 | Krascheninnikovia lanata | 50–150 | – | ||
| 6 | Other shrubs | 45–150 | ||||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–50 | – | ||
| Greene's rabbitbrush | CHGR6 | Chrysothamnus greenei | 0–35 | – | ||
| Shrub (>.5m) | 2SHRUB | Shrub (>.5m) | 0–25 | – | ||
| Apache plume | FAPA | Fallugia paradoxa | 0–25 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 0–25 | – | ||
| pale desert-thorn | LYPA | Lycium pallidum | 0–25 | – | ||
| Fremont's mahonia | MAFR3 | Mahonia fremontii | 0–15 | – | ||
| spineless horsebrush | TECA2 | Tetradymia canescens | 0–15 | – | ||
| Subshrub (<.5m) | 2SUBS | Subshrub (<.5m) | 0–15 | – | ||
| prairie sagewort | ARFR4 | Artemisia frigida | 0–15 | – | ||
| 7 | Succulents | 0–15 | ||||
| Whipple cholla | CYWH | Cylindropuntia whipplei | 0–15 | – | ||
| pricklypear | OPUNT | Opuntia | 0–15 | – | ||
Interpretations
Animal community
Site is favorable for grazing throughout most of the year except when snow cover restricts availability of forage. With continuous grazing use during winter and spring, the relatively scarce cool season mid grasses are replaced by rabbit brush, snakeweed, and lower value forbs and grasses. Planned grazing systems adapt well to use on this site.
The potential plant community produced by this site provides food for those species of wildlife that utilize grass as a major portion of their diet. Some palatable shrubs are also present. When vegetative retrogression occurs, unpalatable shrubby species increase and some wildlife species may benefit.
Recreational uses
This site is found in grassy swales and flood plains characterized by open grasslands interspersed with a few flowering forbs and shrubs.
Winters are cold, however, relatively mild summer months are attractive to recreationists.
Activities include hunting, camping, hiking, and horseback riding.
Supporting information
Type locality
| Location 1: Yavapai County, AZ | |
|---|---|
| General legal description | North West of Prescott, AZ along east side of Willow Creek road and on the Las Vegas Ranch Highway right-of-way. |
Other references
Updates and revisions for this ESD were conducted as part of a 2007-2012 Interagency Technical Assistance Agreement between the Bureau of Indian Affairs–Navajo Region and the NRCS-Arizona.
Contributors
Ken Gishi
Larry D. Ellicott
Steve Barker
Approval
Kendra Moseley, 5/02/2024
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | Karlyn Huling, Kenneth Gishi (2012 revision) |
|---|---|
| Contact for lead author | State Rangeland Management Specialist, NRCS-Arizona State Office, Phoenix, AZ |
| Date | 03/13/2006 |
| Approved by | Byron Lambeth |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
Some rill formation is possible due to loamy surface textures, moderate permeability, and occasional to very frequent flooding. -
Presence of water flow patterns:
Water flow patterns are common due to moderate permeability of the soils and occasional to very frequent flooding. Water flow patterns should not be connected. -
Number and height of erosional pedestals or terracettes:
Pedestals and terracettes may be common due to moderate permeability of the soils and the occasional to very frequent flooding. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
This site should have a relatively low percentage of bare ground because it has the potential for high plant productivity. The high available water capacity of 10 inches (average) combined with the periodic input of water from flooding contributes to this high productivity. Drought may cause an increase in bare ground. Bare ground should be less than 25 percent. -
Number of gullies and erosion associated with gullies:
Occasional gullies may form due to the occasional to very frequent flooding, but should be stable with vegetation and have no active signs of erosion. -
Extent of wind scoured, blowouts and/or depositional areas:
None -
Amount of litter movement (describe size and distance expected to travel):
Herbaceous, fine woody and coarse woody litter will be transported throughout the site during periodic flood events. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface textures range from fine sandy loams to sandy clay loam, but are mostly very fine sandy loam to loam. Coarse fragments are not common. When well vegetated and not subjected to severe flood events, soils have a low to moderate resistance to water erosion and a moderate to high resistance to wind erosion. Expected soil stability ratings without canopy should range 3-4 and ratings with canopy should range 4-5. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil structure is either platy (weak, fine to thick) or granular (weak to moderate, very fine to fine). The surface thickness ranges from 2-10 inches, but is mostly 2-6 inches. Color is variable depending upon parent materials. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
This site is characterized by a even distribution of mostly perennial grasses, with some scattered shrubs and a few forbs. The plant distribution varies across the landscape depending upon local soil characteristics and hydrology. These characteristics are modified periodically by flood events. Both canopy and basal cover decreases during a prolonged drought. This type of plant community structure is very efficient at capturing and storing precipitation. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. Some of the soils can easily be compacted due to loamy textures, lack of rock fragments and frequent moisture from flooding and occasional high water tables. About half the soils in this site have a naturally platy surface structure. -
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Cool season colonizing grass > warm season bunch grasses >Sub-dominant:
cool season bunch grasses > warm season colonizing grasses > large shrubs >Other:
Low shrubs > forbs > cactiAdditional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
All plant functional groups are adapted to survival in all but the most severe droughts. Severe winter droughts affect trees and shrubs most. Severe summer droughts affect grasses the most. -
Average percent litter cover (%) and depth ( in):
Mostly herbaceous litter with some woody litter. Litter amounts increase during the first few years of drought, then decrease in later years. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Expected production of 1500 pounds per acre in a average of year of precipitation. -
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
Broom snakeweed, rubber rabbitbrush and opuntia (pricklypear and cholla cactus) are all native to the site, but have the potential to increase and dominate the area after unmanaged grazing. Salt cedar (tamarisk) is an non-native shrub that can invade and dominate the site, especially in areas that have a high water table or that have been channelized. -
Perennial plant reproductive capability:
All plants native to this site are adapted and are capable of producing seeds, stolons and rhizomes in all but the most severe drought.
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