Natural Resources
Conservation Service
Ecological site R035XB219AZ
Sandy Loam Upland 6-10" p.z.
Accessed: 12/22/2024
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
“PROVISIONAL ecological site concepts developed and described. See Project Plan [insert Project Plan Name] for more details and related milestones.”
This ecological site occurs in Land Resource Area 35.2 - the Colorado Plateau Shrub – Grasslands
Elevations range from 3800-5800 feet and precipitation averages 6 to 10 inches per year. Vegetation includes shadscale, fourwing saltbush, Mormon tea, blackbrush, Indian ricegrass, galleta, blue grama, and black grama. The soil temperature regime is mesic and the soil moisture regime is typic 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) Atriplex canescens |
| Herbaceous |
(1) Bouteloua eriopoda |
Physiographic features
This site occurs in an upland position. It neither benefits significantly from run-in of moisture nor does it suffer from excessive loss of moisture from runoff, unless denuded of its vegetative cover. It is on gently sloping to rolling plains and slopes are mainly less than 12 percent.
Table 2. Representative physiographic features
| Landforms |
(1)
Fan remnant
(2) Plain |
|---|---|
| Flooding frequency | None to very rare |
| Elevation | 1,372 – 1,768 m |
| Slope | 0 – 12% |
| Aspect | Aspect is not a significant factor |
Climatic features
Area has a very dry and windy climate that is hot in the summer and cold in the winter. Average annual precipitation is from 6 to 10 inches. Soil moisture regime is typic aridic and the soil temperature regime is mesic. A slight majority of the precipitation arrives during the late fall, winter, and early spring. this winter season moisture originates in the Pacific Ocean and arrives as rain, or sometimes snow, during widespread frontal storms of generally low intensity. The majority of the snow falls from December through February, but rarely lasts more than a few days. The driest period is from late May to early July. Summer rains occur from July through September during brief intense local thunderstorms. The rain is sporadic in intensity and location. Windy conditions are common year round with the strongest most frequently in the spring.
Table 3. Representative climatic features
| Frost-free period (average) | 181 days |
|---|---|
| Freeze-free period (average) | 207 days |
| Precipitation total (average) | 254 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils in this ecological site are deep and have no plant root restricting layer.
The surface horizon texture is sandy loam to loamy sand about 4 to 10 inches thick.
The subsurface horizons have textures ranging from sandy clay loam to loamy sand. There may be thin strata of finer or coarser material.
The permeability ranges from moderate to rapid and can absorb and hold all of the moisture the climate supplies.
Typical taxonomic units include:
SSA 633 Navajo County Central - MU's 5 Kinan, 20, 21, 46 & 60 Grieta;
SSA-707 Little Colorado River Area MU's 33 Moffat, 30, 33 & 51 Monue;
SSA 711 Navajo Mountain Area - MU's 30 & 51 Monue, 62 Nakai;
SSA 713 Chinle Area - MU's 31 & 32 Monue, 32 Nakai, 46 Marcou;
SSA 714 Hopi - MU's 22, 23 & 33 Nakai, 15 Kinan, 5 Doak, 5, 20, 23 & 32 Monue;
SSA 715 Fort Defiance Area AZ/NM MU’s 38 & 106 Grieta family, 56 & 58 Marcou family 62,63,64,65,67,92,107 & 111 Monue, 66 Monue family, 67 Nakai, 70 Norkiki family, 91,93 & 108 Shiprock family, 106 Grieta family, & 111 Sogzie;
SSA 717 Shiprock NM - MU's 120 & 240 Nageezi, 173 & 205 Shiprock, 506 Blackston, 502 Sogzie;
SSA 689 Glen Canyon Area UT MU's 42 Nepalto, 16 Myton & 36 Seeg.
SSA 619 Chaco Canyon Area NM - MU's 04, 010 Yelives;
SSA 692 McKinley County Area NM - 235 Yelives
Table 4. Representative soil features
| Parent material |
(1)
Alluvium
–
sandstone
|
|---|---|
| Surface texture |
(1) Sandy loam (2) Loamy sand |
| Family particle size |
(1) Loamy |
| Drainage class | Moderately well drained to well drained |
| Permeability class | Moderate to rapid |
| Soil depth | 102 – 152 cm |
| Surface fragment cover <=3" | 0 – 5% |
| Surface fragment cover >3" | 0% |
| Available water capacity (0-101.6cm) |
10.16 – 17.78 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0 – 12% |
| Electrical conductivity (0-101.6cm) |
0 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 – 5 |
| Soil reaction (1:1 water) (0-101.6cm) |
6.6 – 7.9 |
| Subsurface fragment volume <=3" (Depth not specified) |
0 – 5% |
| Subsurface fragment volume >3" (Depth not specified) |
0% |
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 of 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 Model - R035XB219AZ
More interactive model formats are also available.
View Interactive Models
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 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Reference State
Community 1.1
Mixed Native Grassland (HCPC)
This site is a mixed native grassland made up primarily of short and mid grasses with scattered shrubs and a small percentage of forbs and annuals. There is a mixture of both cool and warm season grasses. Dominate grasses include black grama, Indian ricegrass, blue grama with various other grasses like dropseeds, needle and thread and squirretail. Plant species most likely to invade or increase on this site when it starts to deteriorate are cacti, wooly groundsel, broom snakeweed, rabbitbrush, Russian thistle and cheatgrass. Continuous 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 (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Grass/Grasslike | 325 | 600 | 785 |
| Shrub/Vine | 59 | 110 | 143 |
| Forb | 18 | 34 | 43 |
| Total | 402 | 744 | 971 |
Table 6. Soil surface cover
| Tree basal cover | 0% |
|---|---|
| Shrub/vine/liana basal cover | 0-3% |
| Grass/grasslike basal cover | 5-15% |
| Forb basal cover | 0-3% |
| Non-vascular plants | 0% |
| Biological crusts | 0-15% |
| Litter | 15-35% |
| Surface fragments >0.25" and <=3" | 0-5% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 30-50% |
Table 7. Canopy structure (% cover)
| Height Above Ground (m) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.15 | – | 1-5% | 15-25% | 1-5% |
| >0.15 <= 0.3 | – | 1-5% | 1-10% | 0-2% |
| >0.3 <= 0.6 | – | 1-5% | 0-5% | – |
| >0.6 <= 1.4 | – | – | – | – |
| >1.4 <= 4 | – | – | – | – |
| >4 <= 12 | – | – | – | – |
| >12 <= 24 | – | – | – | – |
| >24 <= 37 | – | – | – | – |
| >37 | – | – | – | – |
Figure 6. Plant community growth curve (percent production by month). AZ3521, 35.2 6-10" p.z. all sites. Growth begins in the spring and continues through the summer. Most growth in this CRA occurs in the spring using stored winter moisture..
| 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 | 1 | 9 | 20 | 27 | 14 | 10 | 11 | 5 | 3 | 0 | 0 |
Figure 7. Plant community growth curve (percent production by month). AZ5202, Indian ricegrass, 35.2 6-10" p.z.. Growth begins in spring, most growth occurs in May, goes dormant during summer heat..
| 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 | 10 | 15 | 40 | 20 | 0 | 0 | 10 | 5 | 0 | 0 |
Figure 8. Plant community growth curve (percent production by month). AZ5204, 35.2 6-10" p.z. bottlebrush squirreltail. Most growth occurs in the spring, plants may remain green during the winter..
| 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 | 5 | 40 | 40 | 5 | 0 | 0 | 0 | 0 | 5 | 5 | 0 |
Figure 9. Plant community growth curve (percent production by month). AZ5211, 35.2 6-10" p.z. fourwing saltbush. Growth begins in spring and continues through the summer. Seed stalk extension occurs in summer with seed set in the fall..
| 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 | 10 | 15 | 20 | 20 | 15 | 10 | 5 | 0 | 0 |
Community 1.2
Shrubland/Grassland
Figure 10. 1.2 Shrub Grassland
This plant community is characterized by a shrub overstory with a native perennial grass and forb understory. There is mix of large and low growing shrubs distributed across the site. Dominant shrub species include fourwing saltbush, rabbitbrush, snakeweed and mormontea. Dominant perennial grasses include galleta, Indian ricegrass, blue grama and dropseeds. Other perennial grasses, shrubs, and forbs may or may not be present in smaller amounts.
Pathway 1.1a
Community 1.1 to 1.2
Favorable climate (wet), lack of natural fire, herbivory by wildlife/insect, domestic grazing promote the increase of shrub species with a decrease in herbaceous plant cover.
Pathway 1.2a
Community 1.2 to 1.1
Domestic/wildlife grazing, winter/spring drought, natural fire are disturbance that can result in a reduction in shrubs and promote the developed of perennial grasses.
State 2
Current Potential - Introduction of Non-Native Annuals State
Community 2.1
Mixed Native Grassland w/ Introduced Annuals
This plant community phase is similar to the mixed native grassland, but with minor amounts of non-native annuals now present. It generally reacts to climatic fluctuations and moderate grazing much like the mixed native grassland community. The natural variation in the plant community from year to year and over time closely resembles that of the 1.1 plant community. Disturbances, such as moderate herbivory, only result in a slight increase in the amount of non-native annual grasses and forbs. This site is made up primarily of short and mid grasses with scattered shrubs and a small percentage of forbs and annuals. Dominate grasses include black grama, Indian ricegrass, blue grama with various other grasses like dropseeds, needle and thread and squirretail. Continuous 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.
Community 2.2
Shrubland/Grassland w/ Introduced Annuals
This plant community is characterized by a shrub overstory with native perennial grass and forb along with minor amounts of non-native annuals present in the understory. There is mix of large and low growing shrubs distributed across the site. Dominant shrub species include fourwing saltbush, rabbitbrush, snakeweed and mormontea. Dominant perennial grasses include galleta, Indian ricegrass, blue grama and dropseeds. Other perennial grasses, shrubs, and forbs may or may not be present in smaller amounts.
Community 2.3
Warm Season Grasses w/ Introduced Annuals
This plant community is characterized as a perennial warm season grassland with only occasional scattered shrubs, small percentage of forbs and minor amounts of non-native annuals. Dominant grasses include blue grama, gallate, dropseeds with lesser amounts of Indian ricegrass. Shrubs present include fourwing saltbush, mormon tea, snakeweed and winterfat. Other perennial grasses, shrubs, and forbs my or may not be present.
Pathway 2.1b
Community 2.1 to 2.2
Continous improper grazing, favorable climate (wet), lack of natural fire, herbivory by wildlife/insect promote the increase of shrub species with a decrease in herbaceous plant cover.
Pathway 2.1a
Community 2.1 to 2.3
Improper continuous grazing, drought, wildlife/insect herbivory can all promote the dominance of warm season grass species. Continous grazing during winter and spring periods will result in a decrease of cool season grasses.
Pathway 2.2a
Community 2.2 to 2.1
Domestic/wildlife grazing, winter/spring drought, natural fire are disturbance that can result in a reduction in shrubs and promote the developed of perennial grasses.
Pathway 2.3a
Community 2.3 to 2.2
prescribed grazing, favorable climate can promote the increase of favorable cool season grasses and shrub species.
Pathway 2.3b
Community 2.3 to 2.2
Continous improper grazing, favorable climate (wet), lack of natural fire, herbivory by wildlife/insect promote the increase of shrub species with a decrease in herbaceous plant cover.
State 3
Degraded State
This state is degraded due to a loss of hydrologic function due to increased size of bare ground patches and connected, reduced soil stability and active rill formation and water flow patterns.
Community 3.1
Blue grama/Galleta with Snakeweed
This site is comprised mostly of blue grama and galleta, broom snakeweed along with other native grasses and shrubs. Other shrubs in moderate amounts include rabbitbrush and mormon tea. Because snakeweed tends to be very cyclic in nature, some site will have various amounts of snakeweed. More desirable species may or not be present in minor amounts. Native and non-native annual forbs and grasses are present and can make up to 15% composition by weight.
State 4
Annuals State
Community 4.1
Annual Forbs and Grasses
This site is dominated by native and exotic annual forbs and grasses with a mix of half shrubs and small amounts of perennial grasses and forbs. Annuals present may include Russian thistle, cheatgrass, goosefoot, , false buffalograss, stickseed, blazingstar, wooly plaintain, cryptantha, filaree, globemallow along with other forbs and grasses.The extremely competitive and opportunistic nature of these annual plants creates an extremely harsh environment for any remaining native perennial grasses and their seedlings. Common grasses include galleta, blue grama, threeawns, and sand dropseed. Common shrubs present include snakeweed, mormon tea, rabbitbrush, yucca, prickly pear. The site will not improve without significant inputs and intensive vegetative management. Native and non-native annual forbs and grasses are present and can make up to 50% composition by weight.
Transition T1A
State 1 to 2
The introduction of non-native annual grasses and forbs creates an irreversible change in the plant community.
Transition T2A
State 2 to 3
Improper Grazing result in a decline of perennial herbaceous cover, especially of more desirable forage species. Loss of hydrologic function due to increased size of bare ground patches, reduced soil stability and active rill formation and water flow patterns.
Transition T2B
State 2 to 4
Prolong drought, Continous Improper Grazing and/or fire event result in a significant decline of shrub and perennial grass cover, especially of more desirable forage species.
Restoration pathway R3A
State 3 to 2
This pathway may be possible over time with removal of all surface disturbance and allow for natural plant regeneration, if a nearby seed source is available. However, this may take several years to decades to occur. Accelerated vegetation practices, such as range planting and prescribed grazing may be needed to restore the site.
Transition T3A
State 3 to 4
Prolong drought, Continous Improper Grazing and/or fire event result in a significant decline or loss of shrub and perennial grass cover, especially of more desirable forage species
Restoration pathway R4A
State 4 to 3
May be possible thru the complete removal of all surface disurbances, reseeding, Time/Rest for perennial plant establishment, prescribed grazing. Herbicide treatment may be needed if noxious/invasive species are present. This pathway may not be feasible to implement due to time, cost and marginal climate for seeding.
Additional community tables
Table 8. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 0 | 160–364 | |||||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 73–183 | – | ||
| needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 37–73 | – | ||
| New Mexico feathergrass | HENE5 | Hesperostipa neomexicana | 0–37 | – | ||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 15–37 | – | ||
| 1 | 256–364 | |||||
| black grama | BOER4 | Bouteloua eriopoda | 110–219 | – | ||
| blue grama | BOGR2 | Bouteloua gracilis | 73–183 | – | ||
| bush muhly | MUPO2 | Muhlenbergia porteri | 0–37 | – | ||
| sideoats grama | BOCU | Bouteloua curtipendula | 0–37 | – | ||
| 2 | 73–146 | |||||
| James' galleta | PLJA | Pleuraphis jamesii | 37–110 | – | ||
| alkali sacaton | SPAI | Sporobolus airoides | 8–37 | – | ||
| 3 | 37–110 | |||||
| sand dropseed | SPCR | Sporobolus cryptandrus | 37–73 | – | ||
| mesa dropseed | SPFL2 | Sporobolus flexuosus | 8–37 | – | ||
| spike dropseed | SPCO4 | Sporobolus contractus | 8–37 | – | ||
| 4 | 22–37 | |||||
| threeawn | ARIST | Aristida | 8–15 | – | ||
| low woollygrass | DAPU7 | Dasyochloa pulchella | 8–15 | – | ||
| ring muhly | MUTO2 | Muhlenbergia torreyi | 8–15 | – | ||
| burrograss | SCBR2 | Scleropogon brevifolius | 8–15 | – | ||
|
Forb
|
||||||
| 5 | 22–37 | |||||
| bluebowls | GIAC4 | Giliastrum acerosum | 8–15 | – | ||
| Indian rushpea | HOGL2 | Hoffmannseggia glauca | 8–15 | – | ||
| Forb, perennial | 2FP | Forb, perennial | 0–15 | – | ||
| globemallow | SPHAE | Sphaeralcea | 8–15 | – | ||
| Rocky Mountain zinnia | ZIGR | Zinnia grandiflora | 8–15 | – | ||
| shaggy dwarf morning-glory | EVNU | Evolvulus nuttallianus | 0–8 | – | ||
| flatspine stickseed | LAOC3 | Lappula occidentalis | 0–8 | – | ||
| shortstem lupine | LUBR2 | Lupinus brevicaulis | 0–8 | – | ||
| whitestem blazingstar | MEAL6 | Mentzelia albicaulis | 0–8 | – | ||
| woolly plantain | PLPA2 | Plantago patagonica | 0–8 | – | ||
| Forb, annual | 2FA | Forb, annual | 0–8 | – | ||
|
Shrub/Vine
|
||||||
| 6 | 73–146 | |||||
| fourwing saltbush | ATCA2 | Atriplex canescens | 29–73 | – | ||
| jointfir | EPHED | Ephedra | 22–37 | – | ||
| winterfat | KRLA2 | Krascheninnikovia lanata | 22–37 | – | ||
| 7 | 22–37 | |||||
| Bigelow sage | ARBI3 | Artemisia bigelovii | 8–15 | – | ||
| sand sagebrush | ARFI2 | Artemisia filifolia | 8–15 | – | ||
| shadscale saltbush | ATCO | Atriplex confertifolia | 8–15 | – | ||
| buckwheat | ERIOG | Eriogonum | 8–15 | – | ||
| 8 | 8–37 | |||||
| rabbitbrush | CHRYS9 | Chrysothamnus | 8–15 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 8–15 | – | ||
| pale desert-thorn | LYPA | Lycium pallidum | 8–15 | – | ||
| pricklypear | OPUNT | Opuntia | 8–15 | – | ||
| yucca | YUCCA | Yucca | 8–15 | – | ||
| 9 | 8–15 | |||||
| stretchberry | FOPUP | Forestiera pubescens var. pubescens | 8–15 | – | ||
| skunkbush sumac | RHTR | Rhus trilobata | 8–15 | – | ||
Interpretations
Animal community
This site is suitable for yearlong grazing by either cows and calves or stocker cattle and is easily traversed by all classes of livestock. Prescribed Grazing systems adapt very well to use on this site. Soils on this site are susceptable to erosion, particularly on overgrazed areas, roads, cattle trails and concentration areas.
This site offers some food and cover for selected species of wildlife. In higher condition classes the site is most suitable to grassland wildlife species. As retrogression occurs, food species decrease and cover forms increase.
Recreational uses
Site is typically low, gently rolling plains and fans. It produces high desert grasslands which can be very picturesque.
Winters are cold, however, relatively mild spring, fall and summer months are attractive to recreationists.
Activities include hunting, cross-country riding, photography, hiking, rock collecting, and wildlife observation.
Supporting information
Type locality
| Location 1: Coconino County, AZ | |
|---|---|
| General legal description | South slope of Tucker Mesa, Turquoise Ranch, 7 miles northwest of Winslow, AZ. |
| Location 2: Navajo County, AZ | |
| Township/Range/Section | T19N R22E S31 |
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
Holbrook ESD Office
K. 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) | Ken Gishi, Dan Carroll, Dean Schlichting |
|---|---|
| Contact for lead author | State Rangeland Management Specialist, NRCS-Arizona State Office |
| Date | 07/01/2008 |
| Approved by | |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None -
Presence of water flow patterns:
Very few expected. Some indistinct short water flow patterns may occur on soils with steeper slopes. These soils have moderate to rapid permeability and moderate runoff. -
Number and height of erosional pedestals or terracettes:
None, but some mounding (about 1-2 inches) around long-lived perennial grasses and large shrubs is common. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground averages about 30 to 50 percent. -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
Uncommon, Some deposition may occur when site is adjacent to Sandy Uplands and/or Sandy washes. There should be no wind scoured areas or blowouts. -
Amount of litter movement (describe size and distance expected to travel):
Majority of herbaceous and fine woody litter will be transported by wind with a smaller percentage moving in water flow pathways. Coarse woody litter will remain under shrub canopies. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Surface textures are loamy fine sand, fine sandy loam and sandy loam with thickness ranging from 3-10 inches. Soil aggregate stability ratings should average 3-4 under plant canopies and 2-3 in the interspaces. A thin crust (biological or physical) may occur on this site and can provide some surface protection. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil surface structure is weakly granular. Surface textures are loamy fine sand, fine sandy loam and sandy loam with thickness ranging from 3-10 inches. Surface color can be variable depending of 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 mixed of short and midgrasses with a small percentage of scattered shrubs and forbs. The plant community by weight consists of about 80% grasses, 15% shrubs, 5% forbs. Basal cover range from 10-20% (Grasses,80-90% >> Shrubs,5-10% > forbs,1-5%).
Due to the slope, soil texture and plant community composition, this site is moderately effective at storing precipitation. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. Most of the soils are not easily compacted, due to granular structure. Some of the soils may have a thin platy 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:
warm season colonizing grasses > cool season bunch grasses >Sub-dominant:
warm season bunch grasses > shrubsOther:
forbs > cacti and other succulentsAdditional:
-
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 shrubs most. Severe summer droughts affect grasses the most -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Average annual production on this site is expected to be 575 to 675 lbs/ac in a year of average annual production. -
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, Mormon tea, and burro grass are native to the site, but have the potential to increase and dominate after heavy grazing. Cheatgrass and red brome are exotic annual grasses that have the potential to invade and dominate, with or without disturbance. Russian thistle and redstem storks bill are exotic forbs that have the potential to invade and dominate the site after heavy grazing and/or disturbance, especially if the site is near farm fields or disturbed lands. -
Perennial plant reproductive capability:
All plants native to this site are adapted to the climate and are capable of producing seeds, stolons and rhizomes except during 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.
Click on box and path labels to scroll to the respective text.