Natural Resources
Conservation Service
Ecological site R041XC312AZ
Loamy Bottom
12-16" p.z.
Last updated: 4/12/2021
Accessed: 04/20/2026
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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.
Click to explore map
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 41.3 – Chihuahuan – Sonoran Semidesert Grasslands
Elevations range from 3200 to 5000 feet and precipitation ranges from 12 to 16 inches per year. Vegetation includes mesquite, catclaw acacia, netleaf hackberry, palo verde, false mesquite, range ratany, fourwing saltbush, tarbush, littleleaf sumac, sideoats grama, black grama, plains lovegrass, cane beardgrass, tobosa, vine mesquite, threeawns, Arizona cottontop and bush muhly. The soil temperature regime is thermic and the soil moisture regime is ustic 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
R041XC311AZ Loamy Swale 12-16" p.z.
Similar sites
R041XA114AZ Loamy Bottom 16-20" p.z.
R041XC302AZ Clayey Swale 12-16" p.z.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) sporobolus wrightii
Physiographic features
This site occurs in the middle elevations of the Madrean Basin and Range province in southeastern Arizona. It occurs on floodplains and low stream terraces of major drainage ways and first and second order tributaries. It benefits on a regular basis from extra moisture received as over-bank flooding. It also benefits from shallow water tables at depths of 5-20 feet; or from subsurface clay lenses that perch available water for growth after flood events.
Table 2. Representative physiographic features
Landforms (1) Flood plain
(2) Stream terrace
Flooding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Flooding frequency Occasional to frequent Ponding duration Very brief (4 to 48 hours) Ponding frequency None to rare Elevation 3200 – 5000 ft Slope 0 – 2 % Aspect Aspect is not a significant factor Climatic features
Precipitation in this common resource area ranges from 12-16 inches yearly in the eastern part with elevations from 3600-5000 feet, and 13-17 inches in the western part where elevations are 3300-4500 feet. Winter-Summer rainfall ratios are 40-60% in the west and 30-70% in the east. Summer rains fall July-September, originate in the Gulf of Mexico and are convective, usually brief, intense thunderstorms. Cool season moisture tends to be frontal, originates in the Pacific and Gulf of California, and falls in widespread storms with long duration and low intensity. Snow rarely lasts more than one day. May and June are the driest months of the year. Humidity is generally very low.
Temperatures are mild. Freezing temperatures are common at night from December-April; however temperatures during the day are frequently above 50 F. Occasionally in December-February, brief 0 F temperatures may be experienced some nights. During June, July and August, some days may exceed 100 F.
Cool season plants start growth in early spring and mature in early summer. Warm season plants take advantage of summer rains and are growing and nutritious July-September. Warm season grasses may remain green throughout the year.Table 3 Representative climatic features
Frost-free period (average) 220 days Freeze-free period (average) Precipitation total (average) 20 in 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 young soils on loamy to clayey alluvium of mixed origin. They are deep and dark colored. Plant-soil moisture relationships are excellent.
Soils mapped on this site include: SSA-666 Cochise county Northwest part MU 47 Guest; SSA-667 Santa Cruz area MU's Pm Pima and Ge Grabe; SSA-671 Cochise county Douglas-Tombstone part MU's 84 & 125 Riveroad, 144 Ubik SiL, 145 Ubic L and Ubic L saline-sodic.Table 4. Representative soil features
Surface texture (1) Fine sandy loam
(2) Silt loam
(3) Silty clay loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately slow to moderately rapid Soil depth 60 in Surface fragment cover <=3" 0 – 5 % Surface fragment cover >3" 0 – 1 % Available water capacity
(0-40in)8.4 – 12.6 in Calcium carbonate equivalent
(0-40in)0 – 5 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 2 Soil reaction (1:1 water)
(0-40in)7.4 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 5 % Subsurface fragment volume >3"
(Depth not specified)0 – 1 % 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.
The potential plant community on this site is giant sacaton grassland. Occasional clumps and strands of trees occur along shallow drainage ways and discontinuous gullies. Natural fires during the summer months were important in maintaining the plant community.
The site is very susceptible to gully, channel and bank erosion, especially when the tall grass cover is depleted due to repeated burning and overgrazing or when structures such as dikes, roads, etc., are placed on the floodplain. The lowering of the base level of the axial stream of a watershed will eventually cause channeling of the site. Grade stabilization will be required to prevent deterioration under such conditions. Excessive pumping of ground water can, over time, lower water tables causing depletion of grass cover and site deterioration from gully erosion. With severe erosion, the effectiveness of flooding is reduced, water tables are lowered, the grass cover is thinned and woody plants, especially mesquite, will increase to dominate the plant community. Bermuda grass and Johnson grass are introduced species which can be troublesome on this site.State and transition model
Custom diagramStandard diagram
Figure 4. State and Transition, Loamy Bottom 12-16" 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 textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 6 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant Community
Figure 5. Loamy Bottom 12-16" pz. burned mesquite
The historic native state includes the native plant communities that occur on the site, including the historic climax plant community. This state includes other plant communities that naturally occupy the site following fire, drought, flooding, herbivores, and other natural disturbances. The historic plant community represents the natural climax community that eventually re-occupies the site with proper management.
The potential plant community is dominated by nearly pure stands of giant sacaton. Frequent flooding and groundwater available within the rooting depth of sacaton (20 feet) account for dense and productive stands of grass. Occasional clumps and strands of trees occur along shallow drainages. Naturally occurring fires, June thru September, were an important factor in maintaining the plant community on this site. The aspect is tall grassland.
Mesquite can invade and increase in the native plant community; but high intensity fires can remove even well established mesquite trees as long as sediment accumulation around the stem bases has not occurred. Even repeated fires at these intensities will not remove established mesquite if their bud zones are buried by sediment. The interaction of drought, fire, flooding and grazing can reduce sacaton canopy to 25%. It will recover to normal levels in a short time.
Annual composite forbs like ragweed, goldeneye, sunflower and xanthocephalum can make tremendous stands in wet seasons after fire or drought has opened the grass community.
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 3035 4000 5450 Forb 20 75 600 Tree 10 25 100 Shrub/Vine 0 10 50 Total 3065 4110 6200 Table 6. Soil surface cover
Tree basal cover 0-0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 20-40% Forb basal cover 0-0% Non-vascular plants 0% Biological crusts 0-10% Litter 20-70% Surface fragments >0.25" and <=3" 0-10% Surface fragments >3" 0-0% Bedrock 0% Water 0% Bare ground 10-60% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – 0-5% 0-5% >0.5 <= 1 – – 0-10% 0-5% >1 <= 2 – – 0-5% 0-5% >2 <= 4.5 – 0-2% 30-60% 0-10% >4.5 <= 13 0-2% 0-2% 0-20% 0-5% >13 <= 40 0-2% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 7. Plant community growth curve (percent production by month). AZ4134 , 41.3 12-16" p.z. other sites. Growth begins in the spring, semi-dormancy occurs during the May through June drought, most growth occurs during the summer rains..
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 0 0 30 35 15 5 0 0 State 2
Sacaton, erodedCommunity 2.1
Sacaton, eroded
Figure 8. Loamy Bottom 12-16" pz. gullied
Head-cutting and gully erosion have drained the site. It no longer benefits from extra water received as flooding. The cover of sacaton thins to less than 25%. Groundwater may become out of reach to sacaton roots if incision is deeper than 20 feet. Annual production becomes a function of seasonal rainfall. Annual forbs and grasses may equal sacaton in production.
State 3
Annual Forbs and GrassesCommunity 3.1
Annual Forbs and GrassesSome areas of this state have been created by cultivation for irrigated farming and subsequent abandonment. Former cultivated areas usually have been altered by the diversion of floodwaters with dikes or drainage ditches. In other areas erosion and lowering of water tables have reduced sacaton to less than 5% canopy cover and allowed annual species to dominate. Native and non-native annual forbs and grasses dominate the plant community with minor amounts of sacaton and other native and non-native perennial grasses.
State 4
Non-native perennial grassesCommunity 4.1
Non-native perennial grassesNon-native perennial grasses like Johnson grass, bermuda grass and blue panic dominate the plant community. In some areas this state was made by plowing (and/or burning) of sacaton and seeding of the non-native species. In other areas non-native species invaded from disturbed areas like highway ROWs into areas where the native sacaton stands had been reduced by the interactions of continuous grazing, drought and fire. In other areas this state is a result of the abandonment of cultivated land which is still flooded and had a weed component of the non-native grasses. This state may or may not have a mesquite canopy. Fires can still burn at historic intensities due to the high productivity of grass species with frequent flooding.
State 5
Mesquite, sacatonCommunity 5.1
Mesquite, sacaton
Figure 9. Loamy Bottom 12-16" pz. Mesquite
Mesquite has invaded the site in the absence of fire for long periods of time. Mesquite canopy ranges from 20 to 40%. Trees are well established and the crowns are protected from the heat of surface fires due to sediment accumulation around the stem bases. Sacaton is co-dominant as the state still benefits from frequent flooding and groundwater within the reach of grass roots.
State 6
Mesquite, erodedCommunity 6.1
Mesquite, erodedThe down-cutting of major stream systems and subsequent "valley side" gullying have left many areas of this state along side of rivers like the San Pedro, Santa Cruz and Cienega and Babocomari creeks. Groundwater has dropped beyond the root zone of sacaton (25 feet); but still within the root zone of mesquite (50 feet). The site no longer benefits from flooding. The plant community is dominated by mature mesquite trees with little or no perennial under-story. This state is recognized as a mesquite woodland site as it occurs and forms naturally in the geomorphic dynamics of southwestern stream systems. For details see Forestland site number F041XC310AZ.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant tall grass 3000–5000 big sacaton SPWR2 Sporobolus wrightii 3000–5000 – alkali sacaton SPAI Sporobolus airoides 0–150 – 2 Subdominant perennial grasses 25–200 vine mesquite PAOB Panicum obtusum 0–100 – sideoats grama BOCU Bouteloua curtipendula 0–100 – blue grama BOGR2 Bouteloua gracilis 0–100 – creeping muhly MURE Muhlenbergia repens 0–50 – tobosagrass PLMU3 Pleuraphis mutica 0–50 – 3 Miscellaneous perennial grasses 0–100 cane bluestem BOBA3 Bothriochloa barbinodis 0–50 – Rothrock's grama BORO2 Bouteloua rothrockii 0–25 – Arizona cottontop DICA8 Digitaria californica 0–25 – squirreltail ELELE Elymus elymoides ssp. elymoides 0–25 – green sprangletop LEDU Leptochloa dubia 0–25 – whiplash pappusgrass PAVA2 Pappophorum vaginatum 0–25 – plains bristlegrass SEVU2 Setaria vulpiseta 0–25 – spidergrass ARTE3 Aristida ternipes 0–20 – spidergrass ARTEG Aristida ternipes var. gentilis 0–15 – Orcutt's threeawn ARSCO Aristida schiedeana var. orcuttiana 0–15 – flatsedge CYPER Cyperus 0–15 – mat muhly MURI Muhlenbergia richardsonis 0–15 – bush muhly MUPO2 Muhlenbergia porteri 0–10 – bulrush SCIRP Scirpus 0–10 – spike dropseed SPCO4 Sporobolus contractus 0–10 – plains lovegrass ERIN Eragrostis intermedia 0–10 – mountain rush JUARL Juncus arcticus ssp. littoralis 0–10 – hairy grama BOHI2 Bouteloua hirsuta 0–10 – sedge CAREX Carex 0–5 – sand dropseed SPCR Sporobolus cryptandrus 0–5 – burrograss SCBR2 Scleropogon brevifolius 0–5 – bulb panicgrass PABU Panicum bulbosum 0–5 – bullgrass MUEM Muhlenbergia emersleyi 0–5 – poverty threeawn ARDI5 Aristida divaricata 0–3 – 4 Annual grasses 10–150 feather fingergrass CHVI4 Chloris virgata 0–50 – Mexican sprangletop LEFUU Leptochloa fusca ssp. uninervia 0–50 – sticky sprangletop LEVI5 Leptochloa viscida 0–50 – mucronate sprangeltop LEPAB Leptochloa panicea ssp. brachiata 0–25 – Arizona signalgrass URAR Urochloa arizonica 0–25 – sixweeks fescue VUOC Vulpia octoflora 0–25 – Mexican panicgrass PAHI5 Panicum hirticaule 0–25 – needle grama BOAR Bouteloua aristidoides 0–20 – tapertip cupgrass ERACA Eriochloa acuminata var. acuminata 0–15 – Mexican lovegrass ERME Eragrostis mexicana 0–5 – desert lovegrass ERPEM Eragrostis pectinacea var. miserrima 0–5 – tufted lovegrass ERPEP2 Eragrostis pectinacea var. pectinacea 0–5 – sixweeks threeawn ARAD Aristida adscensionis 0–5 – prairie threeawn AROL Aristida oligantha 0–5 – sixweeks grama BOBA2 Bouteloua barbata 0–5 – Arizona brome BRAR4 Bromus arizonicus 0–5 – delicate muhly MUFR Muhlenbergia fragilis 0–5 – littleseed muhly MUMI Muhlenbergia microsperma 0–5 – witchgrass PACA6 Panicum capillare 0–5 – Bigelow's bluegrass POBI Poa bigelovii 0–5 – Forb5 Perennial Forbs 10–100 sedge CAREX Carex 50–250 – flatsedge CYPER Cyperus 50–250 – slimleaf sneezeweed HELI Helenium linifolium 50–250 – rush JUNCU Juncus 50–250 – Missouri gourd CUFO Cucurbita foetidissima 0–50 – coyote gourd CUPA Cucurbita palmata 0–25 – fingerleaf gourd CUDI Cucurbita digitata 0–25 – weakleaf bur ragweed AMCO3 Ambrosia confertiflora 1–25 – gooseberryleaf globemallow SPGR2 Sphaeralcea grossulariifolia 0–20 – white sagebrush ARLU Artemisia ludoviciana 0–15 – scarlet spiderling BOCO Boerhavia coccinea 0–15 – spreading fleabane ERDI4 Erigeron divergens 0–10 – spear globemallow SPHA Sphaeralcea hastulata 0–10 – canaigre dock RUHY Rumex hymenosepalus 0–10 – Indian rushpea HOGL2 Hoffmannseggia glauca 0–10 – slimleaf bean PHAN3 Phaseolus angustissimus 0–10 – desert globemallow SPAM2 Sphaeralcea ambigua 0–10 – Wright's cudweed PSCAC2 Pseudognaphalium canescens ssp. canescens 0–5 – American vetch VIAM Vicia americana 0–5 – Louisiana vetch VILUL2 Vicia ludoviciana ssp. ludoviciana 0–5 – Trans-Pecos thimblehead HYWI Hymenothrix wislizeni 0–5 – Lewis flax LILE3 Linum lewisii 0–5 – Greene's bird's-foot trefoil LOGR4 Lotus greenei 0–5 – Wright's deervetch LOWR Lotus wrightii 0–5 – woodsorrel OXALI Oxalis 0–5 – Lemmon's ragwort SELE8 Senecio lemmonii 0–5 – New Mexico fanpetals SINE Sida neomexicana 0–5 – silverleaf nightshade SOEL Solanum elaeagnifolium 0–5 – Missouri goldenrod SOMI2 Solidago missouriensis 0–5 – brownplume wirelettuce STPA4 Stephanomeria pauciflora 0–5 – white prairie aster SYFAC Symphyotrichum falcatum var. commutatum 0–5 – beeblossom GAURA Gaura 0–5 – southwestern mock vervain GLGO Glandularia gooddingii 0–5 – small matweed GUDED Guilleminea densa var. densa 0–5 – tarragon ARDR4 Artemisia dracunculus 0–5 – bluedicks DICA14 Dichelostemma capitatum 0–5 – leastdaisy CHAET2 Chaetopappa 0–5 – whitemouth dayflower COER Commelina erecta 0–2 – yerba mansa ANCA10 Anemopsis californica 0–2 – wild dwarf morning-glory EVAR Evolvulus arizonicus 0–2 – jewels of Opar TAPA2 Talinum paniculatum 0–2 – ragged nettlespurge JAMA Jatropha macrorhiza 0–2 – orange fameflower PHAU13 Phemeranthus aurantiacus 0–2 – ivyleaf groundcherry PHHE4 Physalis hederifolia 0–2 – milkweed ASCLE Asclepias 0–1 – 6 Annual forbs 10–500 common sunflower HEAN3 Helianthus annuus 1–200 – San Pedro matchweed XAGY Xanthocephalum gymnospermoides 1–200 – longleaf false goldeneye HELOL Heliomeris longifolia var. longifolia 1–150 – camphorweed HESU3 Heterotheca subaxillaris 0–100 – longleaf false goldeneye HELOA2 Heliomeris longifolia var. annua 1–100 – western tansymustard DEPI Descurainia pinnata 0–50 – carelessweed AMPA Amaranthus palmeri 0–50 – wheelscale saltbush ATEL Atriplex elegans 0–25 – Coulter's spiderling BOCO2 Boerhavia coulteri 0–25 – sensitive partridge pea CHNI2 Chamaecrista nictitans 0–25 – New Mexico thistle CINE Cirsium neomexicanum 0–25 – horseweed CONYZ Conyza 0–15 – cryptantha CRYPT Cryptantha 0–15 – Wright's saltbush ATWR Atriplex wrightii 0–15 – New Mexico copperleaf ACNE Acalypha neomexicana 0–15 – crestrib morning-glory IPCO2 Ipomoea costellata 0–15 – morning-glory IPOMO Ipomoea 0–15 – Arizona poppy KAGR Kallstroemia grandiflora 0–15 – Arizona popcornflower PLAR Plagiobothrys arizonicus 0–15 – intermediate pepperweed LEVIM Lepidium virginicum var. medium 0–15 – Nuttall's povertyweed MONU Monolepis nuttalliana 0–15 – woolly plantain PLPA2 Plantago patagonica 0–10 – purslane PORTU Portulaca 0–5 – desert unicorn-plant PRAL4 Proboscidea althaeifolia 0–5 – doubleclaw PRPA2 Proboscidea parviflora 0–5 – chia SACO6 Salvia columbariae 0–5 – sawtooth sage SASU7 Salvia subincisa 0–5 – spreading fanpetals SIAB Sida abutifolia 0–5 – desert Indianwheat PLOV Plantago ovata 0–5 – rough cocklebur XAST Xanthium strumarium 0–5 – Florida pellitory PAFL3 Parietaria floridana 0–5 – combseed PECTO Pectocarya 0–5 – phacelia PHACE Phacelia 0–5 – phlox PHLOX Phlox 0–5 – foothill deervetch LOHU2 Lotus humistratus 0–5 – coastal bird's-foot trefoil LOSAB Lotus salsuginosus var. brevivexillus 0–5 – Arizona lupine LUAR4 Lupinus arizonicus 0–5 – Coulter's lupine LUSP2 Lupinus sparsiflorus 0–5 – hollowleaf annual lupine LUSU3 Lupinus succulentus 0–5 – slender goldenweed MAGR10 Machaeranthera gracilis 0–5 – tanseyleaf tansyaster MATA2 Machaeranthera tanacetifolia 0–5 – whitestem blazingstar MEAL6 Mentzelia albicaulis 0–5 – warty caltrop KAPA Kallstroemia parviflora 0–5 – goosefoot CHENO Chenopodium 0–5 – shaggyfruit pepperweed LELA Lepidium lasiocarpum 0–5 – miniature woollystar ERDI2 Eriastrum diffusum 0–5 – sorrel buckwheat ERPO4 Eriogonum polycladon 0–5 – California poppy ESCAM Eschscholzia californica ssp. mexicana 0–5 – spurge EUPHO Euphorbia 0–5 – Arizona blanketflower GAAR2 Gaillardia arizonica 0–5 – southwestern pricklypoppy ARPL3 Argemone pleiacantha 0–5 – milkvetch ASTRA Astragalus 0–5 – American wild carrot DAPU3 Daucus pusillus 0–5 – jimsonweed DAST Datura stramonium 0–5 – sacred thorn-apple DAWR2 Datura wrightii 0–5 – scrambled eggs COAU2 Corydalis aurea 0–5 – hoary bowlesia BOIN3 Bowlesia incana 0–5 – golden crownbeard VEEN Verbesina encelioides 0–5 – sleepy silene SIAN2 Silene antirrhina 0–3 – New Mexico plumeseed RANE Rafinesquia neomexicana 0–3 – woolly tidestromia TILA2 Tidestromia lanuginosa 0–2 – Mexican passionflower PAME2 Passiflora mexicana 0–2 – green carpetweed MOVE Mollugo verticillata 0–2 – plains flax LIPU4 Linum puberulum 0–2 – fringed redmaids CACI2 Calandrinia ciliata 0–2 – star gilia GIST Gilia stellata 0–2 – Texas stork's bill ERTE13 Erodium texanum 0–2 – Goodding's bladderpod LEGO2 Lesquerella gooddingii 0–2 – Shrub/Vine7 Miscellaneous shrubs 0–50 fourwing saltbush ATCA2 Atriplex canescens 0–10 – mule-fat BASA4 Baccharis salicifolia 0–10 – Apache plume FAPA Fallugia paradoxa 0–10 – singlewhorl burrobrush HYMO Hymenoclea monogyra 0–10 – American black elderberry SANIC4 Sambucus nigra ssp. canadensis 0–10 – canyon grape VIAR2 Vitis arizonica 0–5 – soaptree yucca YUEL Yucca elata 0–5 – fringed twinevine FUCYC Funastrum cynanchoides ssp. cynanchoides 0–5 – pale desert-thorn LYPA Lycium pallidum 0–5 – catclaw mimosa MIACB Mimosa aculeaticarpa var. biuncifera 0–5 – Texas mulberry MOMI Morus microphylla 0–5 – sacahuista NOMI Nolina microcarpa 0–5 – Drummond's clematis CLDR Clematis drummondii 0–5 – Thurber's desert honeysuckle ANTH2 Anisacanthus thurberi 0–5 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–5 – walkingstick cactus CYSP8 Cylindropuntia spinosior 0–2 – yerba de pasmo BAPT Baccharis pteronioides 0–2 – desertbroom BASA2 Baccharis sarothroides 0–2 – whitethorn acacia ACCO2 Acacia constricta 0–2 – fetid passionflower PAFO2 Passiflora foetida 0–2 – skunkbush sumac RHTR Rhus trilobata 0–2 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–2 – burroweed ISTE2 Isocoma tenuisecta 0–2 – Tree8 Common trees 10–50 desert willow CHLI2 Chilopsis linearis 0–50 – mesquite PROSO Prosopis 0–50 – 9 Miscellaneous trees 0–50 Arizona sycamore PLWR2 Platanus wrightii 0–50 – Fremont cottonwood POFR2 Populus fremontii 0–50 – Goodding's willow SAGO Salix gooddingii 0–25 – western soapberry SASAD Sapindus saponaria var. drummondii 0–10 – netleaf hackberry CELAR Celtis laevigata var. reticulata 0–10 – velvet ash FRVE2 Fraxinus velutina 0–10 – Arizona walnut JUMA Juglans major 0–10 – catclaw acacia ACGR Acacia greggii 0–5 – 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 (%) Table 11. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 12. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 13. Community 6.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Big sacaton begins growth in the spring about mid April. The green season extends through September. Grazing must be concentrated on areas of this site to achieve reasonable utilization of sacaton and keep it in a vegetative state. Heat, humidity and insects are severe enough during summer flooding in July-August , to greatly affect livestock performance. Burning or mowing can be used periodically to freshen old growth sacaton. Burning should be done in February or early March; only in years when November thru February moisture equals or exceeds 4 inches. Burning can be done in July or August, after the first summer rains, to freshen sacaton for winter grazing. Areas of this site should be fenced exclusively for best management of the forage resources. Sacaton is very coarse and unpalatable, but provides adequate nutrition for livestock when green.
Sacaton bottoms are very important habitat for a variety of ground nesting birds and small mammals. They are important cover and foraging areas for javalina, whitetail and mule deer.Hydrological functions
Sacaton floodplains are extremely important in the hydrologic regime of southeastern Arizona stream systems. Intact sacaton floodplains retain floodwaters for 3 to 4 weeks after major flooding events. Channeled or gullied bottomlands often pass the same flood in 2 or 3 days. Water tables in healthy sacaton bottoms range from 5 to 20 feet alongside major streams and creeks and their larger tributaries. In other sacaton bottoms, clay lenses at moderate depths, perch and hold water in the root zone of sacaton after flood events.
Recreational uses
Hunting, bird-watching, hiking, horseback riding, photography.
Wood products
Sacaton bottoms invaded by mesquite furnish large quantities of fuel-wood and posts.
Other products
Sacaton seed
Supporting information
Inventory data references
Range 417s include 1 in excellent condition, 7 in good condition and 6 in fair condition.
Type locality
Location 1: Cochise County, AZ Township/Range/Section T23S R22E S9 General legal description San Pedro River Location 2: Santa Cruz County, AZ Township/Range/Section T21S R19E S18 General legal description Lyle Canyon Location 3: Pima County, AZ Township/Range/Section T19S R17E S11 General legal description Empire Ranch, Key Area 19 in the 5 Wire (east) Pasture. Contributors
Dan Robinett
Larry D. Ellicott
Steve Barker
UnknownApproval
Curtis Talbot, 4/12/2021
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) Wilma Renken, Dave Womack, Emilio Carrillo, Dan Robinett Contact for lead author USDA-NRCS Tucson MLRA Soil Survey Office Date 07/22/2013 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
None Present on this site. -
Presence of water flow patterns:
Uncommon; probably cover no more than 5% of area; very short and discontinuous, 1-3 feet in length. -
Number and height of erosional pedestals or terracettes:
Slope is 0-1% and not conducive to forming pedestals and terracettes. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
3-10% basd on monitoring data. Bare areas are <3 feet in diameter; perennial grasses are evenly distributed. -
Number of gullies and erosion associated with gullies:
Occasional, discontinuous gullies. These gullies can be 50-200 feet in length, 2-5 feet wide and 2-5 feet deep. -
Extent of wind scoured, blowouts and/or depositional areas:
None present on this site. -
Amount of litter movement (describe size and distance expected to travel):
All litter size classes staying in place, occasionally being transported in flow paths. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
No slake test performed. Expect values of 5’s & 6’s across site. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak granular to moderate subangular blocky; Color is 10YR5/2 Dry, 10YR3/2 Moist; thickness to 20+ inches. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Cover estimated as follows: Canopy 47-93%, Basal 17-24%, Litter 65-79%; 95% of canopy cover is perennial tall grasses, 3% is short grasses, and 2 % is grass like and forbs. Short grass species cover occupy scattered patches throughout site. Canopy cover is temporally dynamic. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None present on this site. -
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:
Perennial tall grasses >>Sub-dominant:
short grasses > grasslike species > perennial forbs > annuals grasses & forbs.Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
10-20% basal area lost on short grasses, 5% basal area lost on tall grasses. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
3,500 lbs/acre unfavorable precipitation, 5,000 lbs/acre normal precipitation, 6,500 lbs/acre favorable 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:
mesquite, wait-a-bit, burrobrush, rubber rabbitbrush, johnson grass, bermuda grass. -
Perennial plant reproductive capability:
Not affected even following several years of prolonged drought period for region.
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PrintThe 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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