Natural Resources
Conservation Service
Ecological site R041XB212AZ
Saline Upland
8-12" p.z.
Last updated: 7/28/2020
Accessed: 09/14/2026
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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.
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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): 041X–Madrean Archipelago
AZ 41.2 – Chihuahuan – Sonoran Desert Shrubs
Elevations range from 2600 to 4000 feet and precipitation ranges from 8 to 12 inches per year. Vegetation includes mesquite, palo verde, catclaw acacia, soaptree yucca, creosotebush, whitethorn, staghorn cholla, desert saltbush, Mormon tea, burroweed, snakeweed, tobosa, black grama, threeawns, bush muhly, dropseed, and burrograss. The soil temperature regime is thermic and the soil moisture regime is typic aridic. This unit occurs within the Basin and Range Physiographic Province and is characterized by numerous mountain ranges that rise abruptly from broad, plain-like valleys and basins. Igneous and metamorphic rock classes dominate the mountain ranges and sediments filling the basins represent combinations of fluvial, lacustrine, colluvial and alluvial deposits.Associated sites
F041XB221AZ Loamy Bottom 8-12" p.z. woodland
F041XB222AZ Saline Bottom 8-12" p.z. woodland
R041XB206AZ Limy Fan 8-12" p.z.
R041XB209AZ Loamy Swale 8-12" p.z.
Similar sites
R040XB212AZ Loamy Slopes 7"-10" p.z.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) atriplex polycarpa
Herbaceous Not specified
Physiographic features
This site occurs in the lowest elevations of the Madrean Basin and Range province in southeastern Arizona. It occurs as nearly level to gently sloping fan terraces, stream terraces and alluvial fans.
Table 2. Representative physiographic features
Landforms (1) Alluvial flat
(2) Stream terrace
(3) Fan piedmont
Flooding frequency None Ponding frequency None Elevation 2600 – 4000 ft Slope 0 – 5 % Aspect Aspect is not a significant factor Climatic features
Precipitation ranges from 8-12 inches annually. More than half falls during July-Sep in brief, but often heavy, thunderstorms. The rest of the moisture comes as light rain or snow that falls slowly for a day or more, but rarely lasts more than a day. May and June are normally the driest months. Humidity is generally very low.
Temperatures are mild throughout most of the year. Freezing temperatures are common at night Dec-Feb; brief 0 F may be observed some nights. During June, July & August, some days may exceed 100 F.
In years of average or greater winter precipitation, annual grasses and forbs occur abundantly in the interspaces.Table 3 Representative climatic features
Frost-free period (average) 240 days Freeze-free period (average) Precipitation total (average) BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
There are no water features associated with this site.
Soil features
These are deep, well drained, saline and sodic soils. They are sandy to loamy with a surface cap of loamy fine sand to sandy loam. The plant-soil moisture relationships are poor to fair. These soils take water readily, but water available for plant growth is limited by the saline, sodic conditions.
Soil series mapped to date on this site include: SSA-662 Safford area MU TgA Gila & Glendale; SSA-663 Gila-Duncan area MU 16 Gila; SSA-664 San Simon area MU's 7 Gothard, 28 & 29 Hondale.Table 4. Representative soil features
Surface texture (1) Sandy loam
(2) Fine sandy loam
(3) Silt loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately rapid to moderate Soil depth 60 in Available water capacity
(0-40in)3.6 – 6.2 in Calcium carbonate equivalent
(0-40in)1 – 10 % Electrical conductivity
(0-40in)4 – 30 mmhos/cm Sodium adsorption ratio
(0-40in)6 – 60 Soil reaction (1:1 water)
(0-40in)7.4 – 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 fire, grazing, 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 amount shown for each group. Divide the resulting total by the total normal year production shown in the plant community description. If the 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.State and transition model
Custom diagramStandard diagram
Figure 4. State and Transition, Saline Upland 8-12" p.z.
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 textState 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe native plant community on this site is dominated by salt tolerant shrubs. Winter and summer annual forbs and grasses are well represented on this site. Perennial grasses and forbs are present in trace amounts in the potential vegetative community.
With severe disturbance (such as repeated fire or heavy, continuous grazing) the saltbush species are replaced by annual grasses and forbs. Loss of shrub cover can result in accelerated water and wind erosion. Atriplex species are very sensitive to summer fires on this site.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)Shrub/Vine 150 200 315 Grass/Grasslike 0 20 155 Forb 0 15 100 Total 150 235 570 Table 6. Soil surface cover
Tree basal cover 0% Shrub/vine/liana basal cover 0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 0-20% Litter 10-50% Surface fragments >0.25" and <=3" 0-20% Surface fragments >3" 0-0% Bedrock 0% Water 0% Bare ground 20-100% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 0-1% 0-20% 0-20% >0.5 <= 1 – 0-1% 0-15% 0-10% >1 <= 2 – 5-10% – 0-5% >2 <= 4.5 – 5-10% – – >4.5 <= 13 – – – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – State 2
AnnualsCommunity 2.1
AnnualsThis state usually occurs where the site has been cleared for cultivation and irrigation with subsequent abandonment. Native and non-native annual forbs and grasses dominate the plant community. Exotic annual species include tumbleweed, filaree, mediterranean grass, London rocket, malva weed, foxtail barley, red brome and Sahara mustard.
State 3
Shrubs, exotic annualsCommunity 3.1
Shrubs, exotic annualsThis state occurs where the native saltbush cover is still intact but the herbaceous layer is dominated by non-native annual forbs and grasses. Exotic annuals include mediterranean grass, tumbleweed, filaree, red brome and London rocket. Exotic annuals can reduce the diversity of native species and may influence their ability to maintain themselves in the soil seed bank.
Transition T1A
State 1 to 2Usually results from clearing for irrigated agriculture and subsequent abandonment. Seed source for native shrubs is no longer present.
Transition T1B
State 1 to 3Introduction of a seed source of non-natives. Possible competition of exotics with native species of forbs or grasses.
Restoration pathway R2A
State 2 to 1Unknown
Restoration pathway R
State 3 to 1Unknown
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Perennial grasses 0–5 false Rhodes grass TRCR9 Trichloris crinita 0–5 – alkali sacaton SPAI Sporobolus airoides 0–2 – spike dropseed SPCO4 Sporobolus contractus 0–1 – Parish's threeawn ARPUP5 Aristida purpurea var. parishii 0–1 – spidergrass ARTE3 Aristida ternipes 0–1 – bush muhly MUPO2 Muhlenbergia porteri 0–1 – big galleta PLRI3 Pleuraphis rigida 0–1 – 2 Annual grasses 0–50 needle grama BOAR Bouteloua aristidoides 0–20 – sixweeks grama BOBA2 Bouteloua barbata 0–20 – Rothrock's grama BORO2 Bouteloua rothrockii 0–20 – feather fingergrass CHVI4 Chloris virgata 0–20 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 0–10 – Bigelow's bluegrass POBI Poa bigelovii 0–5 – sixweeks threeawn ARAD Aristida adscensionis 0–5 – prairie threeawn AROL Aristida oligantha 0–5 – sixweeks fescue VUOC Vulpia octoflora 0–5 – Arizona brome BRAR4 Bromus arizonicus 0–2 – Arizona signalgrass URAR Urochloa arizonica 0–2 – witchgrass PACA6 Panicum capillare 0–2 – tapertip cupgrass ERACA Eriochloa acuminata var. acuminata 0–2 – tufted lovegrass ERPEP2 Eragrostis pectinacea var. pectinacea 0–2 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 0–2 – Forb3 Annual forbs 0–100 desert Indianwheat PLOV Plantago ovata 0–25 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–25 – wheelscale saltbush ATEL Atriplex elegans 0–20 – wheelscale saltbush ATELF Atriplex elegans var. fasciculata 0–20 – Coulter's globemallow SPCO2 Sphaeralcea coulteri 0–20 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–10 – combseed PECTO Pectocarya 0–10 – Nuttall's povertyweed MONU Monolepis nuttalliana 0–10 – Gordon's bladderpod LEGO Lesquerella gordonii 0–10 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–5 – intermediate pepperweed LEVIM Lepidium virginicum var. medium 0–5 – manybristle chinchweed PEPA2 Pectis papposa 0–5 – phacelia PHACE Phacelia 0–5 – common fiddleneck AMMEI2 Amsinckia menziesii var. intermedia 0–5 – slender goldenweed MAGR10 Machaeranthera gracilis 0–2 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 0–2 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–2 – canaigre dock RUHY Rumex hymenosepalus 0–2 – sleepy silene SIAN2 Silene antirrhina 0–2 – aridland goosefoot CHDE Chenopodium desiccatum 0–2 – miniature woollystar ERDI2 Eriastrum diffusum 0–2 – Texas stork's bill ERTE13 Erodium texanum 0–2 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 0–2 – fringed amaranth AMFI Amaranthus fimbriatus 0–2 – fringed redmaids CACI2 Calandrinia ciliata 0–2 – yellow tackstem CAPA7 Calycoseris parryi 0–2 – white tackstem CAWR Calycoseris wrightii 0–2 – whitemargin sandmat CHAL11 Chamaesyce albomarginata 0–1 – cryptantha CRYPT Cryptantha 0–1 – American wild carrot DAPU3 Daucus pusillus 0–1 – coastal bird's-foot trefoil LOSA Lotus salsuginosus 0–1 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–1 – bristly nama NAHI Nama hispidum 0–1 – desert evening primrose OEPR Oenothera primiveris 0–1 – Shrub/Vine4 Dominant shrub 150–250 cattle saltbush ATPO Atriplex polycarpa 150–250 – 5 Miscellaneous shrubs 0–40 fourwing saltbush ATCA2 Atriplex canescens 0–10 – mound saltbush ATOB Atriplex obovata 0–10 – creosote bush LATR2 Larrea tridentata 0–10 – water jacket LYAN Lycium andersonii 0–10 – western honey mesquite PRGLT Prosopis glandulosa var. torreyana 0–10 – lotebush ZIOB Ziziphus obtusifolia 0–1 – pale desert-thorn LYPA Lycium pallidum 0–1 – 6 Half shrubs 0–15 Griffiths' saltbush ATGR2 Atriplex griffithsii 0–10 – seepweed SUAED Suaeda 0–5 – burrobush AMDU2 Ambrosia dumosa 0–5 – shadscale saltbush ATCO Atriplex confertifolia 0–5 – 7 Succulents 0–10 Christmas cactus CYLE8 Cylindropuntia leptocaulis 0–5 – devil's cholla GRKU Grusonia kunzei 0–5 – Engelmann's hedgehog cactus ECEN Echinocereus engelmannii 0–1 – candy barrelcactus FEWI Ferocactus wislizeni 0–1 – Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site produces forage for year-round use by livestock. Salt desert shrub species will provide adequate protein throughout the year, however, energy will usually be lacking from Jun-Jan (except when summer rains are sufficient to produce a crop of summer annual grasses and forbs). Spring is the main season for plant growth and production of annual species. Proper use of the shrub species should be no more than 50% of the spring production of twigs and leaves. Water developments are very important to both livestock and wildlife on the site.
Lack of natural water and poor cover limits the value of this site as wildlife habitat. The site is mainly home to small desert animals and a forage area for birds.Hydrological functions
These soils are medium textured and poor producers of runoff.
Recreational uses
Hunting, horseback riding, hiking, four wheeling.
Supporting information
Contributors
Dan Robinett
Larry D. EllicottApproval
Scott Woodall, 7/28/2020
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) Contact for lead author Date 09/14/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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