Natural Resources
Conservation Service
Ecological site DX035X01I113
Loamy Upland 10-14" p.z.
Accessed: 11/13/2024
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
“ATTENTION: This ecological site meets the requirements for PROVISIONAL (if not more). A provisional ecological site is established after ecological site concepts are developed and an initial state-and-transition model is drafted. A provisional ecological site typically will include literature reviews, land use history information, legacy data (prior approved range site descriptions, forage suitability groups, woodland suitability groups, etc.,) , and includes some soils data, and estimates for canopy and/or species composition by weight,. A provisional ecological site provides the conceptual framework of soil-site correlation for the development of the ESD. For more information about this ecological site, please contact your local NRCS office.”
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Krascheninnikovia lanata |
Herbaceous |
(1) Bouteloua eriopoda |
Legacy ID
R035XA113AZ
Physiographic features
This ecological site occurs in an upland position as gently rolling plains, fans and terraces. Slopes generally range from 0% to 15% with occasional steeper slopes up to 30%.
This site neither benefits significantly from run-in nor experiences excessive loss of moisture from runoff.
Table 2. Representative physiographic features
Landforms |
(1)
Plateau
(2) Fan (3) Terrace |
---|---|
Flooding frequency | None |
Elevation | 4,800 – 6,300 ft |
Slope | 15% |
Aspect | Aspect is not a significant factor |
Climatic features
50-60% of moisture falls as rain from July through September and is the most effective moisture for plant growth. The remaining moisture comes as snow during the winter.
Mean temperature for the hottest month (July) is 72 F; for the coldest month (January) 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 by early summer. Warm season plants take advantage of summer rains and actively grow from July through September.
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
This site neither benefits significantly from run-in moisture nor experiences excessive loss of moisture from runoff.
Soil features
Soils grouped in this site are moderately deep or deeper to any plant root restricting layers. The surface horizons have textures of very fine sandy loam to sandy clay loam with various amounts of gravel on the surface. The surface layers are about 2 to 8 inches thick. The subsurface horizons have textures ranging from clay to loam with coarse fragments ranging from 0 to 40% by volume. The substratum, which occurs at depths of 15 to 36 or more inches, ranges from clay loam to very gravelly sand and in some soils has a strong accumulation of lime. The soil reaction is neutral to moderately alkaline (pH 6.6 to 8.4). Soluble salt accumulations are low.
Typical taxonomic units include:
Coconino County Central (AZ631) Soil Map Units-2-Aut grL, 3-Aut,4-Aut, 31-Poley grL, 32- Poley, 33-Poley, 35-Quivera grvL, 46-Tenorio grvSL;
Navajo County Central (AZ633) Soil Map Units -5-Barx, 6-Barx, 47-Poley, 62-Sheeza, 71-Ustollic haplargids;
Apache County Central (AZ635) Soil Map Units-Cob-Clovis, CoB-Clovis, CoC-Clovis, CsB-Clovis, CsC-Clovis, JoB-Jocity, HUB-Hubert, HUC2-Hubert, HEB-Hereford, HEB-Hereford, HeB-Hereford, HeC- Hereford, HfB-Hereford, HhB-Hereford heavy varient, HrC-Hereford heavy varient, MGD-Millett;
Yavapai County Western (AZ637)Soil Map Units- PlB-Poley, Po-Poley, Pp-Poley;
Mohave County Central (AZ697)Soil Map Units-115-Quagwa;
Hualapai/Havasupai (AZ699) Soil Map Units- 37-Quagwa, 32-Barx, 34-Poley;
Little Colorado River Area (AZ707) Soil Map Units - 2-Aut, 63-Tuweep;
Navajo Mountain Area (AZ711) Soil Map Units - 27-Gish (moderately deep), 64-Ustic Haplocambids, 65-Ustic haplargids;
Chinle Area (AZ713) Soil Map Units- 39-Gish;
Fort Defiance (AZ715) Soil Map Units - 35 Flaco and 80-Penistaja family.
Table 4. Representative soil features
Parent material |
(1)
Pyroclastic flow
–
basalt
(2) Alluvium – limestone |
---|---|
Surface texture |
(1) Very fine sandy loam (2) Sandy clay loam (3) Very gravelly loam |
Family particle size |
(1) Loamy |
Drainage class | Moderately well drained to well drained |
Permeability class | Moderate to slow |
Soil depth | 40 – 60 in |
Surface fragment cover <=3" | 25% |
Surface fragment cover >3" | Not specified |
Available water capacity (0-40in) |
7.7 – 7.9 in |
Calcium carbonate equivalent (0-40in) |
5 – 40% |
Electrical conductivity (0-40in) |
4 mmhos/cm |
Sodium adsorption ratio (0-40in) |
2 |
Soil reaction (1:1 water) (0-40in) |
6.6 – 8.4 |
Subsurface fragment volume <=3" (Depth not specified) |
40% |
Subsurface fragment volume >3" (Depth not specified) |
Not specified |
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 (HCPC) 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 and research is available, these plant communities may be revised, removed, and even added to reflect the ecological dynamics of this site.
State and transition model
Figure 4. State and Transition - R035XA113AZ
More interactive model formats are also available.
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More interactive model formats are also available.
View Interactive Models
Click on state and transition labels to scroll to the respective text
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Reference State
The reference state includes the Historic Climax Plant Community (HCPC). The HCPC plant community is a pernnial native grassland with warm season and cool season grasses and half-shrubs. Natural climatic variation can result in changes in the amount of and ratio of both individual plants and warm season versus cool season plants, particularly grasses.
Community 1.1
Perennial Native Grassland
The reference state plant community is composed primarily of warm season mid-grasses and short grasses with a mix of cool season grasses and half-shrubs. Dominant grasses include black grama, blue grama, squirreltail, indian ricegrass, galleta and sideoats grama. Dominant shrubs include winterfat and fourwing saltbush. Natural climatic variation result in changes in the amount of and ratio of both individual plants and warm season versus cool season plants, particularly grasses.
Figure 6. 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 | 300 | 390 | 480 |
Shrub/Vine | 130 | 180 | 220 |
Tree | 15 | 20 | 25 |
Forb | 15 | 20 | 25 |
Total | 460 | 610 | 750 |
Table 6. Soil surface cover
Tree basal cover | 0-1% |
---|---|
Shrub/vine/liana basal cover | 0-5% |
Grass/grasslike basal cover | 15-25% |
Forb basal cover | 0-5% |
Non-vascular plants | 0-1% |
Biological crusts | 0-1% |
Litter | 5-15% |
Surface fragments >0.25" and <=3" | 0-2% |
Surface fragments >3" | 0% |
Bedrock | 0% |
Water | 0% |
Bare ground | 45-55% |
Table 7. Canopy structure (% cover)
Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
---|---|---|---|---|
<0.5 | – | 0-5% | 10-20% | 1-2% |
>0.5 <= 1 | – | 0-5% | 5-15% | 0-2% |
>1 <= 2 | – | 5-10% | 0-1% | 0-1% |
>2 <= 4.5 | 0-5% | 1-5% | 0-1% | 0-1% |
>4.5 <= 13 | 0-5% | – | – | – |
>13 <= 40 | – | – | – | – |
>40 <= 80 | – | – | – | – |
>80 <= 120 | – | – | – | – |
>120 | – | – | – | – |
Figure 7. Plant community growth curve (percent production by month). AZ3502, 35.1 10-14" p.z. black grama. Growth occurs mostly during the summer to early fall 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 | 0 | 5 | 15 | 30 | 30 | 15 | 5 | 0 | 0 |
Figure 8. 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 9. 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
Grassland/Shrubland
The grassland/shrubland plant community is characterized by an increase of composite shrubs (Greene's rabbitbrush and snakeweed) and succulents (Mormon tea, Yucca and cholla) along with desirable shrub species, such as winterfat and fourwing saltbush. Dominate grasses include blue grama, galleta, sand dropseed and Indian ricegrass.
Community 1.3
Grassland/Shrubland with Juniper
This plant community is characterized by an increase of juniper and/or other woody species. The general aspect of the site is a grassland with scattered shrubs with widely scattered juniper with canopy less than 10 percent. The grass component is largely dominated by warm season grasses, such as blue grama, galleta, dropseeds and black grama with a mix of cool season grasses. The shrub component is a mix of snakeweed, rabbitbrush, Yucca, winterfat and fourwing saltbush. The dominate shrubs are mainly comprised of composites, Mormon tea, Yucca and fourwing saltbush.
Pathway 1.1B
Community 1.1 to 1.2
Continous heavy herbivory, unmanaged grazing and summer droughts can result in a decline of the herbaceous dominance.
Pathway 1.1A
Community 1.1 to 1.3
Continous heavy herbivory and/or unmanaged grazing and lack of natural fire promotes the increase of woody species.
Pathway 1.2A
Community 1.2 to 1.1
Insect/wildlife herbivory, possible natural patchy fire
Pathway 1.2B
Community 1.2 to 1.3
Lack of natural fire and other disturbances, climate cycle of wet periods, seed source for junipers
Pathway 1.3A
Community 1.3 to 1.1
Favorable moisture, fire, insect/wildlife herbivory
Pathway 1.3B
Community 1.3 to 1.2
Prolonged drought and/or patchy fire removes trees.
State 2
Juniper Overstory State
In this state the plant communities are characterized by a dominance of juniper and other woody species. Juniper has increased due to lack of fire/exclusion along with unmanaged grazing and available seed source for juniper. The overstory canopy of juniper is typically over 10 percent and can range up to 25 percent. The understory is dominanted by either grasses and/or shrubs with increased forbs.
Community 2.1
Juniper Overstory with Grass Understory
This site is characterized by an increase of juniper canopy greater than 10% with a herbaceous understory dominated by warm season grasses with lesser amounts of forbs and shrubs. Grasses are comprised mostly of blue grama, galleta and dropseeds. Shrubs are mainly comprised of snakeweed, rabbitbrush, yucca and Mormon tea. A lack of fire, lack of grazing management and above normal winter precipitation result in an increase of juniper and cool season annual forbs. Non-native annuals may be present in minor amounts.
Community 2.2
Juniper Overstory with Shrub Understory
This site is characterized by an increase of juniper canopy greater than 10% with dominate shrubs mainly comprised of snakeweed, rabbitbrush, Mormon tea and yucca. Grasses are comprised mostly of blue grama and galleta with an increase in forbs. A lack of fire, lack of grazing management and above normal winter precipitation results in an increase of juniper and cool season annual forbs. Non-native annuals may be present in minor amounts.
Pathway 2.1A
Community 2.1 to 2.2
Countinous heavy herbivory, unmanaged grazing and drought
Pathway 2.2A
Community 2.2 to 2.1
Managed grazing and favorable precipitation.
State 3
Invaded Annuals State
This state has a mix of forbs, shrubs and grasses, but can be degraded to a mixed annual plant community. Dominant shrubs are Greene's rabbitbrush and snakeweed with scattered cacti and yucca. Grasses are a mix of perennial warm season and annuals, while forbs are dominated by annual natives and exotics. Annual forb composition can range from 20 to 60 percent with a sharp decline in perennial herbacous composition.
Community 3.1
Shrubs with Mixed Annuals
This plant community is comprised mainly of native and non-native annuals with scattered shrubs and perennial grasses. Perennial grasses may not be present in this plant community. Annual forbs and grasses can make up to 55 percent of the plant coomunity composition.
Community 3.2
Mixed Annuals
This site has a degraded plant community dominanted by both native and non-native annuals. Annual grasses and forbs composition is over 35 percent of the total plant community. Common annuals include Russian thistle, false buffalo grass, cheatgrass, plantain, stickseed, scorpionweed, globemallows, buckwheats, nightshade and blazingstar. Perennial grasses and/or shrubs may or not be present.
Pathway 3.1A
Community 3.1 to 3.2
Unmanaged grazing and prolonged droughts, particularly summer droughts.
Pathway 3.2A
Community 3.2 to 3.1
Favorable climate/precipitation and a seed source for perennial grasses along with grazing management allows for some recovery of perennial species.
Transition T1A
State 1 to 2
Increase of Juniper and woody species, due to lack of fire, unmanaged grazing and proximity to seed source and along with favorable precipition.
Transition T1B
State 1 to 3
Unmanaged grazing, drought, other surface disturbance and establishment/ seed source of invasive species. Lack of herbaceous perennial cover with increased bare ground.
Restoration pathway 2A
State 2 to 1
Juniper removal thru woody species control/prescribed burning, herbaceous species reseeding and grazing management.
Conservation practices
Brush Management | |
---|---|
Grazing Land Mechanical Treatment | |
Range Planting | |
Vegetated Treatment Area | |
Prescribed Grazing |
Transition 2A
State 2 to 3
Reduced tree canopy thru wood harvesting or fire, improper grazing management, drought and annual seed sources
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 | 300–450 | ||||
black grama | BOER4 | Bouteloua eriopoda | 85–120 | – | ||
blue grama | BOGR2 | Bouteloua gracilis | 90–110 | – | ||
sideoats grama | BOCU | Bouteloua curtipendula | 30–80 | – | ||
Indian ricegrass | ACHY | Achnatherum hymenoides | 30–60 | – | ||
squirreltail | ELELE | Elymus elymoides ssp. elymoides | 30–60 | – | ||
James' galleta | PLJA | Pleuraphis jamesii | 30–60 | – | ||
muttongrass | POFE | Poa fendleriana | 5–30 | – | ||
needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 5–30 | – | ||
western wheatgrass | PASM | Pascopyrum smithii | 5–30 | – | ||
2 | Other grasses | 30–65 | ||||
Grass, perennial | 2GP | Grass, perennial | 0–10 | – | ||
threeawn | ARIST | Aristida | 5–10 | – | ||
common wolfstail | LYPH | Lycurus phleoides | 5–10 | – | ||
mat muhly | MURI | Muhlenbergia richardsonis | 5–10 | – | ||
ring muhly | MUTO2 | Muhlenbergia torreyi | 5–10 | – | ||
spike dropseed | SPCO4 | Sporobolus contractus | 5–10 | – | ||
sand dropseed | SPCR | Sporobolus cryptandrus | 5–10 | – | ||
mesa dropseed | SPFL2 | Sporobolus flexuosus | 5–10 | – | ||
Forb
|
||||||
3 | All forbs | 7–35 | ||||
Forb, perennial | 2FP | Forb, perennial | 4–20 | – | ||
Forb, annual | 2FA | Forb, annual | 3–15 | – | ||
Shrub/Vine
|
||||||
4 | Dominant shrubs | 35–65 | ||||
fourwing saltbush | ATCA2 | Atriplex canescens | 20–40 | – | ||
winterfat | KRLA2 | Krascheninnikovia lanata | 15–25 | – | ||
5 | Other shrubs | 5–30 | ||||
rough menodora | MESC | Menodora scabra | 5–15 | – | ||
jointfir | EPHED | Ephedra | 2–10 | – | ||
buckwheat | ERIOG | Eriogonum | 2–10 | – | ||
6 | Misc. shrubs | 0–20 | ||||
sand sagebrush | ARFI2 | Artemisia filifolia | 0–5 | – | ||
prairie sagewort | ARFR4 | Artemisia frigida | 0–5 | – | ||
Greene's rabbitbrush | CHGR6 | Chrysothamnus greenei | 0–5 | – | ||
rubber rabbitbrush | ERNAG | Ericameria nauseosa ssp. nauseosa var. glabrata | 0–5 | – | ||
snakeweed | GUTIE | Gutierrezia | 0–5 | – | ||
New Mexico groundsel | PANE7 | Packera neomexicana | 0–5 | – | ||
spineless horsebrush | TECA2 | Tetradymia canescens | 0–5 | – | ||
7 | Succulents | 5–30 | ||||
buckhorn cholla | CYACA2 | Cylindropuntia acanthocarpa var. acanthocarpa | 3–10 | – | ||
plains pricklypear | OPPO | Opuntia polyacantha | 3–10 | – | ||
yucca | YUCCA | Yucca | 3–10 | – | ||
Tree
|
||||||
8 | Trees | 5–35 | ||||
juniper | JUNIP | Juniperus | 5–20 | – | ||
Fremont's mahonia | MAFR3 | Mahonia fremontii | 3–15 | – |
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 rabbitbrush, 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. When vegetative retrogression occurs, unpalatable shrubby species increase and some wildlife species may benefit.
Recreational uses
This site is located on undulating plains and foot slopes with a variety of spring and summer flowering shrubs and forbs following good moisture. The grassland aspect has good appeal.
Winters are cold, however relatively mild summers make the site attractive to many recreational activities.
Supporting information
Type locality
Location 1: Yavapai County, AZ | |
---|---|
Township/Range/Section | T23N R6W S32 |
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
Dean Schlichting
Ken Gishi
Larry D. Ellicott
Peter Lefebvre
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, Dean Schlichting, Ken Gishi |
---|---|
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:
No rills expected. A few minor rills may form on slopes greater that 5% due to moderate permeability and moderate runoff. -
Presence of water flow patterns:
Water flow patterns are infrequent, short (1 to 2 meters), and poorly developed with less than 10% coverage. They may become more common on steeper slopes due to slow to moderate permeability and medium runoff characteristics of the soils. -
Number and height of erosional pedestals or terracettes:
Pedestals less than 1” may be common and often associated with water flow patterns. Terracettes are infrequent, but they should be short. Both may be more developed and common during a drought, due to moderate wind erosion hazard of the soils. Moderate wind erosion hazard occurs on the soils with a coarse-loamy surface textures. Pedestals and terracettes may be more common, especially on steeper slopes, but they should be short. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground ranges from 30-50%. Drought may cause an increase in bare ground. -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
No blowouts are present on this site. Some small mounding around long-lived perennial plant bases common, especially during droughts, due to low to moderate wind erosion hazard of the soil. -
Amount of litter movement (describe size and distance expected to travel):
Most herbaceous and fine woody litter will be transported by wind and in short water flow pathways, while a small percentage stays in place. Coarse woody litter and duff will accumulate under shrub and tree canopies. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil aggregate stability ratings should average 4-5 (range 3 to 6) under plant canopies and 2-3 (range 1 to 3)in the interspaces. There is usually less than 5% cover of rock fragments on the surface. When well vegetated, soils have a moderate resistance to water erosion and moderate to high resistance to wind erosion -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil structure is mostly granular (weak to moderate, very fine and fine) with some platy (weak, thin and medium) and sub angular blocky (weak, fine to medium). Surface thickness typically ranges from 2-8 inches, but is mostly 2-4 inches. Color is typically reddish brown to brown, but can vary depending on parent material. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
This site is characterized by a relatively even distribution of mostly grasses with some shrubs and a few forbs. This type of plant community is moderately effective at capturing and storing precipitation thus reducing runoff. Cover averages 30-40% (25 to 30% grasses, 5-10% shrubs, 2-5% forbs). Basal plant cover averages 10-20% (15% grasses, 2% shrubs, 1% forbs). Both cover values decrease during a prolonged drought. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
The occurrence of compaction layers should be rare to none. Soils with sandy clay loam and clay loam textures, can be easily compacted when wet, if there are no rock fragments in surface horizons. Some surface horizons are naturally platy. -
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:
>40%: NoneSub-dominant:
11-40%: warm season bunchgrasses > warm season colonizing grasses > shrubs > cool season bunchgrasses >Other:
Minor (3-10%): forbs = cacti = trees(trace)Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
In a normal year up to 10% of grasses and shrubs die off. During and after drought years there can be from 10 to 15% die off of shrubs and grasses. Severe winter droughts affect shrubs, trees and cool season grasses the most. Severe summer droughts affect the warm season grasses the most. -
Average percent litter cover (%) and depth ( in):
Average percent litter cover ranges from 20-40% and depth 1/8”inch. Within plant interspaces litter ranges from 5 to 20% cover ,while under shrub and tree canopies litter can range up to 50% cover with depths from 1/8 to 1/4 inch thick. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Total production ranges from; 300-375 pounds per acre (dry weight) in drought years; 572-725 pounds per acre in average years; 725-800 pounds per acre in wet years. -
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:
Mormon tea (EPVI), Broom snakeweed (GUSA2), Greene''s rabbitbrush (CHGR6), Prickly pear (OPPO), Whipple cholla cactus (CYWH) and false buffalo grass (MUSQ) are all native to the site, but have the ability to increase and dominate the area after unmanaged grazing. Oneseed juniper (JUMO) is native to the site, but has the ability to increase and dominate the site after unmanaged grazing and/or fire exclusion. Russian thistle (SATR12) is an exotic forb that has the ability to increase and dominate the site after heavy grazing and/or ground disturbance. -
Perennial plant reproductive capability:
All plants native to this site are adapted to the climate and are producing seeds, stolons and rhizomes in all but the most severe droughts.
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The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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