Natural Resources
Conservation Service
Ecological site R041XA114AZ
Loamy Bottom 16-20" p.z.
Last updated: 4/09/2021
Accessed: 11/23/2024
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): 041X–Madrean Archipelago
AZ 41.1 – Mexican Oak-Pine Forest and Oak Savannah
Elevations range from 4500 to 10,700 feet and precipitation ranges from 16 to 30 inches. Vegetation includes Emory oak, Mexican blue oak, Arizona white oak, one-seed juniper, alligator juniper, sacahuista, California bricklebush, skunkbush sumac, Arizona rosewood, wait-a-bit mimosa, sideoats grama, blue grama, purple grama, wooly bunchgrass, plains lovegrass, squirreltail, and pinyon ricegrass. The soil temperature regime ranges from thermic to mesic and the soil moisture regime ranges from aridic ustic to typic ustic. 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
| F041XA112AZ |
Sandy Wash 16-20" p.z. woodland |
|---|---|
| F041XA113AZ |
Sandy Bottom 16-20" p.z. woodland |
| R041XA104AZ |
Limy Slopes 16-20" p.z. |
| R041XA108AZ |
Loamy Upland 16-20" p.z. |
| R041XA115AZ |
Loamy Swale 16-20" p.z. |
Similar sites
| R041XA115AZ |
Loamy Swale 16-20" p.z. |
|---|---|
| R041XC311AZ |
Loamy Swale 12-16" p.z. |
| R041XC312AZ |
Loamy Bottom 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.
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 | 1,433 – 1,676 m |
| Slope | 0 – 3% |
| Aspect | Aspect is not a significant factor |
Climatic features
Precipitation in this zone of the common resource area ranges from 16-20 inches per year with elevations from 4700-5500 feet. Approximately 40% of this moisture comes as gentle rain or snow during the winter-spring (Oct-Apr) season; originates in the north Pacific and Gulf of California and comes as frontal storms with long duration and low intensity. The remaining 60% falls in the summer season (May-Sep); originates in the Gulf of Mexico and are convective, usually brief, intense thunderstorms. Snow is common Dec-Mar, averaging 5-15 inches per year, but rarely lasts more than a week. May and June are the driest months. Humidity is low.
Temperatures are mild. Freezing temperatures are common at night from Oct-May, but daytime temperatures are almost always over 40 F. Below 0 F temperatures can occur Dec-Feb. Daytime summer highs rarely exceed 95 F.
Species like plains lovegrass, wooly bunchgrass, false mesquite, shrubby buckwheat and ratany begin growth in late March to April. Warm season grasses begin growth in July or August with receipt of the first summer rains.
Table 3. Representative climatic features
| Frost-free period (average) | |
|---|---|
| Freeze-free period (average) | 175 days |
| Precipitation total (average) | 457 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Figure 4. Annual precipitation pattern
Figure 5. Annual average temperature pattern
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-661 Eastern Pinal & Southern Gila counties MU 94 Stanford; SSA-671 Cochise county Douglas-Tombstone part MU 26 Leslie creek.
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 | 152 cm |
| Surface fragment cover <=3" | 0 – 5% |
| Surface fragment cover >3" | 0 – 1% |
| Available water capacity (0-101.6cm) |
21.34 – 32 cm |
| Calcium carbonate equivalent (0-101.6cm) |
0 – 5% |
| Electrical conductivity (0-101.6cm) |
0 – 2 mmhos/cm |
| Sodium adsorption ratio (0-101.6cm) |
0 – 2 |
| Soil reaction (1:1 water) (0-101.6cm) |
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 a giant sacaton grassland. Occasional clumps and strands of trees occur along shallow drainageways 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 main 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
Figure 6. State and Transition, Loamy Bottom 16-20" 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 text
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 1
Reference
Community 1.1
Historic Climax Plant Community
Figure 7. Loamy Bottom 16-20" pz. HCPC
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 occuring 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 8. 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 | 3402 | 4483 | 7229 |
| Forb | 22 | 84 | 673 |
| Tree | 11 | 22 | 168 |
| Shrub/Vine | – | 11 | 56 |
| Total | 3435 | 4600 | 8126 |
Table 6. Soil surface cover
| Tree basal cover | 0-1% |
|---|---|
| Shrub/vine/liana basal cover | 0-1% |
| Grass/grasslike basal cover | 20-40% |
| Forb basal cover | 0-1% |
| Non-vascular plants | 0-1% |
| Biological crusts | 1-5% |
| Litter | 25-65% |
| Surface fragments >0.25" and <=3" | 0-5% |
| Surface fragments >3" | 0-5% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 10-50% |
Table 7. Canopy structure (% cover)
| Height Above Ground (m) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.15 | – | – | 0-5% | 0-5% |
| >0.15 <= 0.3 | – | – | 0-10% | 0-5% |
| >0.3 <= 0.6 | – | – | 0-5% | 0-5% |
| >0.6 <= 1.4 | – | 0-2% | 30-70% | 0-15% |
| >1.4 <= 4 | 0-3% | 0-2% | 0-15% | 0-5% |
| >4 <= 12 | 0-2% | – | – | – |
| >12 <= 24 | – | – | – | – |
| >24 <= 37 | – | – | – | – |
| >37 | – | – | – | – |
Figure 9. Plant community growth curve (percent production by month). AZ4111, 41.1 16-30. Growth begins in the spring, semi-dormancy occurs during the June drought, most growth occurs during the summer rainy season..
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 0 | 0 | 0 | 5 | 10 | 0 | 15 | 45 | 20 | 5 | 0 | 0 |
Community 1.2
Scattered Mesquite
Mesquite and/or alligator juniper are sparsely scattered within the big sacaton grassland. The aspect is a savannah. This community phase rapidly returns to the reference state after summer fire.
State 2
Mesquite, Sacaton
Community 2.1
Tall Grass Savannah
Mesquite has invaded the site in the absence of fire for long periods of time. Mesquite canopy ranges from 5 to 30%. 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 3
Eroded Sacaton
Community 3.1
Sacaton, eroded
Figure 10. Loamy Bottom 16-20" 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 4
Annual Forbs and Grasses
Community 4.1
Annual Forbs and Grasses
Some 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 5
Exotic Grasses
Community 5.1
Non-native grassland
This state occurs where exotic perennial grasses like Johnson grass, common and coastal bermuda, and tall fescue have invaded the native plant community or been seeded on areas of the site. These species tend to make large monotypic patches within stands of sacaton. They may also be the result of cultivation and abandonment, leaving these species as remnants of the weeds that existed.
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
|
||||||
| 1 | Dominant tall grass | 3363–6725 | ||||
| big sacaton | SPWR2 | Sporobolus wrightii | 3363–6725 | – | ||
| alkali sacaton | SPAI | Sporobolus airoides | 0–560 | – | ||
| 2 | Subdominant perennial grasses | 28–224 | ||||
| sideoats grama | BOCU | Bouteloua curtipendula | 0–112 | – | ||
| blue grama | BOGR2 | Bouteloua gracilis | 0–112 | – | ||
| vine mesquite | PAOB | Panicum obtusum | 0–112 | – | ||
| creeping muhly | MURE | Muhlenbergia repens | 0–56 | – | ||
| 3 | Miscellaneous perennial grasses | 0–112 | ||||
| cane bluestem | BOBA3 | Bothriochloa barbinodis | 0–56 | – | ||
| Rothrock's grama | BORO2 | Bouteloua rothrockii | 0–28 | – | ||
| Arizona cottontop | DICA8 | Digitaria californica | 0–28 | – | ||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 0–28 | – | ||
| green sprangletop | LEDU | Leptochloa dubia | 0–28 | – | ||
| whiplash pappusgrass | PAVA2 | Pappophorum vaginatum | 0–28 | – | ||
| plains bristlegrass | SEVU2 | Setaria vulpiseta | 0–28 | – | ||
| deergrass | MURI2 | Muhlenbergia rigens | 0–22 | – | ||
| spidergrass | ARTE3 | Aristida ternipes | 0–22 | – | ||
| spidergrass | ARTEG | Aristida ternipes var. gentilis | 0–17 | – | ||
| Orcutt's threeawn | ARSCO | Aristida schiedeana var. orcuttiana | 0–17 | – | ||
| flatsedge | CYPER | Cyperus | 0–17 | – | ||
| mat muhly | MURI | Muhlenbergia richardsonis | 0–17 | – | ||
| bush muhly | MUPO2 | Muhlenbergia porteri | 0–11 | – | ||
| tobosagrass | PLMU3 | Pleuraphis mutica | 0–11 | – | ||
| spike dropseed | SPCO4 | Sporobolus contractus | 0–11 | – | ||
| Texas bluestem | SCCI2 | Schizachyrium cirratum | 0–11 | – | ||
| bulrush | SCIRP | Scirpus | 0–11 | – | ||
| plains lovegrass | ERIN | Eragrostis intermedia | 0–11 | – | ||
| mountain rush | JUARL | Juncus arcticus ssp. littoralis | 0–11 | – | ||
| silver bluestem | BOSA | Bothriochloa saccharoides | 0–11 | – | ||
| hairy grama | BOHI2 | Bouteloua hirsuta | 0–11 | – | ||
| sand dropseed | SPCR | Sporobolus cryptandrus | 0–6 | – | ||
| burrograss | SCBR2 | Scleropogon brevifolius | 0–6 | – | ||
| purple muhly | MURI3 | Muhlenbergia rigida | 0–6 | – | ||
| bulb panicgrass | PABU | Panicum bulbosum | 0–6 | – | ||
| bullgrass | MUEM | Muhlenbergia emersleyi | 0–6 | – | ||
| sedge | CAREX | Carex | 0–6 | – | ||
| poverty threeawn | ARDI5 | Aristida divaricata | 0–3 | – | ||
| densetuft hairsedge | BUCA2 | Bulbostylis capillaris | 0–1 | – | ||
| common wolfstail | LYPH | Lycurus phleoides | 0–1 | – | ||
| 4 | Annual grasses | 11–168 | ||||
| feather fingergrass | CHVI4 | Chloris virgata | 0–56 | – | ||
| sticky sprangletop | LEVI5 | Leptochloa viscida | 0–56 | – | ||
| Mexican sprangletop | LEFUU | Leptochloa fusca ssp. uninervia | 0–56 | – | ||
| mucronate sprangeltop | LEPAB | Leptochloa panicea ssp. brachiata | 0–28 | – | ||
| Mexican panicgrass | PAHI5 | Panicum hirticaule | 0–28 | – | ||
| Arizona signalgrass | URAR | Urochloa arizonica | 0–28 | – | ||
| sixweeks fescue | VUOC | Vulpia octoflora | 0–28 | – | ||
| needle grama | BOAR | Bouteloua aristidoides | 0–22 | – | ||
| tapertip cupgrass | ERACA | Eriochloa acuminata var. acuminata | 0–17 | – | ||
| Mexican lovegrass | ERME | Eragrostis mexicana | 0–6 | – | ||
| desert lovegrass | ERPEM | Eragrostis pectinacea var. miserrima | 0–6 | – | ||
| tufted lovegrass | ERPEP2 | Eragrostis pectinacea var. pectinacea | 0–6 | – | ||
| sixweeks grama | BOBA2 | Bouteloua barbata | 0–6 | – | ||
| Arizona brome | BRAR4 | Bromus arizonicus | 0–6 | – | ||
| Bigelow's bluegrass | POBI | Poa bigelovii | 0–6 | – | ||
| delicate muhly | MUFR | Muhlenbergia fragilis | 0–6 | – | ||
| littleseed muhly | MUMI | Muhlenbergia microsperma | 0–6 | – | ||
| witchgrass | PACA6 | Panicum capillare | 0–6 | – | ||
| sixweeks threeawn | ARAD | Aristida adscensionis | 0–6 | – | ||
| prairie threeawn | AROL | Aristida oligantha | 0–6 | – | ||
| pitscale grass | HAGR3 | Hackelochloa granularis | 0–1 | – | ||
|
Forb
|
||||||
| 5 | Perennial Forbs | 11–112 | ||||
| sedge | CAREX | Carex | 56–280 | – | ||
| flatsedge | CYPER | Cyperus | 56–280 | – | ||
| slimleaf sneezeweed | HELI | Helenium linifolium | 56–280 | – | ||
| rush | JUNCU | Juncus | 56–280 | – | ||
| Missouri gourd | CUFO | Cucurbita foetidissima | 0–56 | – | ||
| coyote gourd | CUPA | Cucurbita palmata | 0–28 | – | ||
| weakleaf bur ragweed | AMCO3 | Ambrosia confertiflora | 1–28 | – | ||
| fingerleaf gourd | CUDI | Cucurbita digitata | 0–28 | – | ||
| gooseberryleaf globemallow | SPGR2 | Sphaeralcea grossulariifolia | 0–22 | – | ||
| white sagebrush | ARLU | Artemisia ludoviciana | 0–17 | – | ||
| scarlet spiderling | BOCO | Boerhavia coccinea | 0–17 | – | ||
| spreading fleabane | ERDI4 | Erigeron divergens | 0–11 | – | ||
| Indian rushpea | HOGL2 | Hoffmannseggia glauca | 0–11 | – | ||
| spear globemallow | SPHA | Sphaeralcea hastulata | 0–11 | – | ||
| slimleaf bean | PHAN3 | Phaseolus angustissimus | 0–11 | – | ||
| canaigre dock | RUHY | Rumex hymenosepalus | 0–11 | – | ||
| desert globemallow | SPAM2 | Sphaeralcea ambigua | 0–11 | – | ||
| American vetch | VIAM | Vicia americana | 0–6 | – | ||
| Louisiana vetch | VILUL2 | Vicia ludoviciana ssp. ludoviciana | 0–6 | – | ||
| woodsorrel | OXALI | Oxalis | 0–6 | – | ||
| Indianhemp | APCA | Apocynum cannabinum | 0–6 | – | ||
| Wright's cudweed | PSCAC2 | Pseudognaphalium canescens ssp. canescens | 0–6 | – | ||
| brownplume wirelettuce | STPA4 | Stephanomeria pauciflora | 0–6 | – | ||
| white prairie aster | SYFAC | Symphyotrichum falcatum var. commutatum | 0–6 | – | ||
| Lemmon's ragwort | SELE8 | Senecio lemmonii | 0–6 | – | ||
| New Mexico fanpetals | SINE | Sida neomexicana | 0–6 | – | ||
| silverleaf nightshade | SOEL | Solanum elaeagnifolium | 0–6 | – | ||
| Missouri goldenrod | SOMI2 | Solidago missouriensis | 0–6 | – | ||
| Trans-Pecos thimblehead | HYWI | Hymenothrix wislizeni | 0–6 | – | ||
| Lewis flax | LILE3 | Linum lewisii | 0–6 | – | ||
| Greene's bird's-foot trefoil | LOGR4 | Lotus greenei | 0–6 | – | ||
| Wright's deervetch | LOWR | Lotus wrightii | 0–6 | – | ||
| beeblossom | GAURA | Gaura | 0–6 | – | ||
| southwestern mock vervain | GLGO | Glandularia gooddingii | 0–6 | – | ||
| small matweed | GUDED | Guilleminea densa var. densa | 0–6 | – | ||
| leastdaisy | CHAET2 | Chaetopappa | 0–6 | – | ||
| bluedicks | DICA14 | Dichelostemma capitatum | 0–6 | – | ||
| tarragon | ARDR4 | Artemisia dracunculus | 0–6 | – | ||
| Cuman ragweed | AMPS | Ambrosia psilostachya | 0–6 | – | ||
| melon loco | APUN | Apodanthera undulata | 0–2 | – | ||
| yerba mansa | ANCA10 | Anemopsis californica | 0–2 | – | ||
| whitemouth dayflower | COER | Commelina erecta | 0–2 | – | ||
| wild dwarf morning-glory | EVAR | Evolvulus arizonicus | 0–2 | – | ||
| ragged nettlespurge | JAMA | Jatropha macrorhiza | 0–2 | – | ||
| jewels of Opar | TAPA2 | Talinum paniculatum | 0–2 | – | ||
| orange fameflower | PHAU13 | Phemeranthus aurantiacus | 0–2 | – | ||
| ivyleaf groundcherry | PHHE4 | Physalis hederifolia | 0–2 | – | ||
| slimflower scurfpea | PSTE5 | Psoralidium tenuiflorum | 0–1 | – | ||
| buffpetal | RHPH2 | Rhynchosida physocalyx | 0–1 | – | ||
| Texas snoutbean | RHSET | Rhynchosia senna var. texana | 0–1 | – | ||
| slimleaf plainsmustard | SCLI12 | Schoenocrambe linearifolia | 0–1 | – | ||
| narrowleaf stoneseed | LIIN2 | Lithospermum incisum | 0–1 | – | ||
| variableleaf bushbean | MAGI2 | Macroptilium gibbosifolium | 0–1 | – | ||
| lemon beebalm | MOCIA | Monarda citriodora ssp. austromontana | 0–1 | – | ||
| tufted evening primrose | OECA10 | Oenothera caespitosa | 0–1 | – | ||
| scarlet beeblossom | GACO5 | Gaura coccinea | 0–1 | – | ||
| trailing fleabane | ERFL | Erigeron flagellaris | 0–1 | – | ||
| New Mexico fleabane | ERNE3 | Erigeron neomexicanus | 0–1 | – | ||
| Mexican fireplant | EUHE4 | Euphorbia heterophylla | 0–1 | – | ||
| birdbill dayflower | CODI4 | Commelina dianthifolia | 0–1 | – | ||
| Texas bindweed | COEQ | Convolvulus equitans | 0–1 | – | ||
| Arizona milkvetch | ASAR6 | Astragalus arizonicus | 0–1 | – | ||
| spider milkweed | ASAS | Asclepias asperula | 0–1 | – | ||
| milkweed | ASCLE | Asclepias | 0–1 | – | ||
| broadleaf milkweed | ASLA4 | Asclepias latifolia | 0–1 | – | ||
| horsetail milkweed | ASSU2 | Asclepias subverticillata | 0–1 | – | ||
| 6 | Annual forbs | 11–560 | ||||
| common sunflower | HEAN3 | Helianthus annuus | 1–224 | – | ||
| San Pedro matchweed | XAGY | Xanthocephalum gymnospermoides | 1–224 | – | ||
| longleaf false goldeneye | HELOL | Heliomeris longifolia var. longifolia | 1–168 | – | ||
| camphorweed | HESU3 | Heterotheca subaxillaris | 0–112 | – | ||
| longleaf false goldeneye | HELOA2 | Heliomeris longifolia var. annua | 1–112 | – | ||
| western tansymustard | DEPI | Descurainia pinnata | 0–56 | – | ||
| carelessweed | AMPA | Amaranthus palmeri | 0–56 | – | ||
| wheelscale saltbush | ATEL | Atriplex elegans | 0–28 | – | ||
| Coulter's spiderling | BOCO2 | Boerhavia coulteri | 0–28 | – | ||
| sensitive partridge pea | CHNI2 | Chamaecrista nictitans | 0–28 | – | ||
| New Mexico thistle | CINE | Cirsium neomexicanum | 0–28 | – | ||
| crestrib morning-glory | IPCO2 | Ipomoea costellata | 0–17 | – | ||
| flaxflowered ipomopsis | IPLOL | Ipomopsis longiflora ssp. longiflora | 0–17 | – | ||
| Arizona poppy | KAGR | Kallstroemia grandiflora | 0–17 | – | ||
| intermediate pepperweed | LEVIM | Lepidium virginicum var. medium | 0–17 | – | ||
| Nuttall's povertyweed | MONU | Monolepis nuttalliana | 0–17 | – | ||
| Arizona popcornflower | PLAR | Plagiobothrys arizonicus | 0–17 | – | ||
| horseweed | CONYZ | Conyza | 0–17 | – | ||
| cryptantha | CRYPT | Cryptantha | 0–17 | – | ||
| Wright's saltbush | ATWR | Atriplex wrightii | 0–17 | – | ||
| New Mexico copperleaf | ACNE | Acalypha neomexicana | 0–17 | – | ||
| woolly plantain | PLPA2 | Plantago patagonica | 0–11 | – | ||
| purslane | PORTU | Portulaca | 0–6 | – | ||
| desert unicorn-plant | PRAL4 | Proboscidea althaeifolia | 0–6 | – | ||
| doubleclaw | PRPA2 | Proboscidea parviflora | 0–6 | – | ||
| Wright's cudweed | PSCAC2 | Pseudognaphalium canescens ssp. canescens | 0–6 | – | ||
| Florida pellitory | PAFL3 | Parietaria floridana | 0–6 | – | ||
| combseed | PECTO | Pectocarya | 0–6 | – | ||
| Mangas Spring phacelia | PHBO4 | Phacelia bombycina | 0–6 | – | ||
| rough cocklebur | XAST | Xanthium strumarium | 0–6 | – | ||
| golden crownbeard | VEEN | Verbesina encelioides | 0–6 | – | ||
| sawtooth sage | SASU7 | Salvia subincisa | 0–6 | – | ||
| spreading fanpetals | SIAB | Sida abutifolia | 0–6 | – | ||
| warty caltrop | KAPA | Kallstroemia parviflora | 0–6 | – | ||
| shaggyfruit pepperweed | LELA | Lepidium lasiocarpum | 0–6 | – | ||
| foothill deervetch | LOHU2 | Lotus humistratus | 0–6 | – | ||
| coastal bird's-foot trefoil | LOSAB | Lotus salsuginosus var. brevivexillus | 0–6 | – | ||
| shortstem lupine | LUBR2 | Lupinus brevicaulis | 0–6 | – | ||
| bajada lupine | LUCOC | Lupinus concinnus ssp. concinnus | 0–6 | – | ||
| slender goldenweed | MAGR10 | Machaeranthera gracilis | 0–6 | – | ||
| tanseyleaf tansyaster | MATA2 | Machaeranthera tanacetifolia | 0–6 | – | ||
| whitestem blazingstar | MEAL6 | Mentzelia albicaulis | 0–6 | – | ||
| El Paso skyrocket | IPTH2 | Ipomopsis thurberi | 0–6 | – | ||
| scrambled eggs | COAU2 | Corydalis aurea | 0–6 | – | ||
| poorjoe | DITE2 | Diodia teres | 0–6 | – | ||
| Abert's buckwheat | ERAB2 | Eriogonum abertianum | 0–6 | – | ||
| miniature woollystar | ERDI2 | Eriastrum diffusum | 0–6 | – | ||
| sorrel buckwheat | ERPO4 | Eriogonum polycladon | 0–6 | – | ||
| California poppy | ESCAM | Eschscholzia californica ssp. mexicana | 0–6 | – | ||
| Arizona blanketflower | GAAR2 | Gaillardia arizonica | 0–6 | – | ||
| southwestern pricklypoppy | ARPL3 | Argemone pleiacantha | 0–6 | – | ||
| milkvetch | ASTRA | Astragalus | 0–6 | – | ||
| American wild carrot | DAPU3 | Daucus pusillus | 0–6 | – | ||
| jimsonweed | DAST | Datura stramonium | 0–6 | – | ||
| sacred thorn-apple | DAWR2 | Datura wrightii | 0–6 | – | ||
| hoary bowlesia | BOIN3 | Bowlesia incana | 0–6 | – | ||
| pitseed goosefoot | CHBE4 | Chenopodium berlandieri | 0–6 | – | ||
| hyssopleaf sandmat | CHHY3 | Chamaesyce hyssopifolia | 0–6 | – | ||
| New Mexico goosefoot | CHNE3 | Chenopodium neomexicanum | 0–6 | – | ||
| sleepy silene | SIAN2 | Silene antirrhina | 0–3 | – | ||
| woolly tidestromia | TILA2 | Tidestromia lanuginosa | 0–2 | – | ||
| Mexican passionflower | PAME2 | Passiflora mexicana | 0–2 | – | ||
| lesser yellowthroat gilia | GIFL | Gilia flavocincta | 0–2 | – | ||
| sweet four o'clock | MILO2 | Mirabilis longiflora | 0–2 | – | ||
| Goodding's bladderpod | LEGO2 | Lesquerella gooddingii | 0–2 | – | ||
| green carpetweed | MOVE | Mollugo verticillata | 0–2 | – | ||
| plains flax | LIPU4 | Linum puberulum | 0–2 | – | ||
| fringed redmaids | CACI2 | Calandrinia ciliata | 0–2 | – | ||
| El Paso gilia | GIME | Gilia mexicana | 0–1 | – | ||
| Dakota mock vervain | GLBIB | Glandularia bipinnatifida var. bipinnatifida | 0–1 | – | ||
| Abert's creeping zinnia | SAAB | Sanvitalia abertii | 0–1 | – | ||
|
Shrub/Vine
|
||||||
| 7 | Miscellaneous shrubs | 0–56 | ||||
| mule-fat | BASA4 | Baccharis salicifolia | 0–11 | – | ||
| Apache plume | FAPA | Fallugia paradoxa | 0–11 | – | ||
| American black elderberry | SANIC4 | Sambucus nigra ssp. canadensis | 0–11 | – | ||
| canyon grape | VIAR2 | Vitis arizonica | 0–6 | – | ||
| soaptree yucca | YUEL | Yucca elata | 0–6 | – | ||
| rubber rabbitbrush | ERNA10 | Ericameria nauseosa | 0–6 | – | ||
| fringed twinevine | FUCYC | Funastrum cynanchoides ssp. cynanchoides | 0–6 | – | ||
| Drummond's clematis | CLDR | Clematis drummondii | 0–6 | – | ||
| pale desert-thorn | LYPA | Lycium pallidum | 0–6 | – | ||
| catclaw mimosa | MIACB | Mimosa aculeaticarpa var. biuncifera | 0–6 | – | ||
| Texas mulberry | MOMI | Morus microphylla | 0–6 | – | ||
| sacahuista | NOMI | Nolina microcarpa | 0–6 | – | ||
| Thurber's desert honeysuckle | ANTH2 | Anisacanthus thurberi | 0–6 | – | ||
| yerba de pasmo | BAPT | Baccharis pteronioides | 0–2 | – | ||
| skunkbush sumac | RHTR | Rhus trilobata | 0–2 | – | ||
| walkingstick cactus | CYSP8 | Cylindropuntia spinosior | 0–2 | – | ||
| singlewhorl burrobrush | HYMO | Hymenoclea monogyra | 0–1 | – | ||
|
Tree
|
||||||
| 8 | Miscellaneous trees | 11–168 | ||||
| Arizona sycamore | PLWR2 | Platanus wrightii | 1–168 | – | ||
| Fremont cottonwood | POFR2 | Populus fremontii | 0–56 | – | ||
| desert willow | CHLI2 | Chilopsis linearis | 1–34 | – | ||
| Goodding's willow | SAGO | Salix gooddingii | 0–28 | – | ||
| Arizona walnut | JUMA | Juglans major | 1–28 | – | ||
| velvet ash | FRVE2 | Fraxinus velutina | 1–22 | – | ||
| netleaf hackberry | CELAR | Celtis laevigata var. reticulata | 0–11 | – | ||
| western soapberry | SASAD | Sapindus saponaria var. drummondii | 0–11 | – | ||
| catclaw acacia | ACGR | Acacia greggii | 0–6 | – | ||
| western honey mesquite | PRGLT | Prosopis glandulosa var. torreyana | 0–2 | – | ||
| velvet mesquite | PRVE | Prosopis velutina | 0–2 | – | ||
Interpretations
Animal community
Big sacaton begins growth in the spring from April 15 to May 1st. The green season extends into 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 and 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.
Recreational uses
Hunting, bird-watching, hiking, horseback riding, photography.
Wood products
Sacaton bottoms invaded by mesquite furnish large quantities of fuelwood and posts.
Other products
Sacaton seed
Supporting information
Inventory data references
Range 417s include 1 in excellent condition and 1 in good condition.
Type locality
| Location 1: Santa Cruz County, AZ | |
|---|---|
| Township/Range/Section | T21S R18E S22 |
| General legal description | Audubon Research Ranch, O'Donnell Canyon bottom. |
| Location 2: Santa Cruz County, AZ | |
| General legal description | San Rafael Ranch, Santa Cruz River bottom |
Contributors
Dan Robinett
Larry D. Ellicott
Approval
Curtis Talbot, 4/09/2021
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, Dan Robinett, Larry Humphrey, Linda Kennedy |
|---|---|
| Contact for lead author | USDA-NRCS Tucson MLRA Soil Survey Office |
| Date | 05/01/2014 |
| Approved by | Curtis Talbot |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
None -
Presence of water flow patterns:
None present. Water movement is even sheet flow lacking energy. -
Number and height of erosional pedestals or terracettes:
Pedestals (2-4" height) common on big sacaton plants; pedestals disappear after fire and reform within 10 years after fire. No terracettes. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
10% bare ground with bare areas 2-5 ft in diameter common across site. Bare ground exposed after fire is covered with litter within 1-2 years after burning. -
Number of gullies and erosion associated with gullies:
Discontinuous gullies, although infrequent, are occasionally present. When present, gullies are generally 100-200ft in length, 1-3ft wide, and 1-3 ft deep. -
Extent of wind scoured, blowouts and/or depositional areas:
None -
Amount of litter movement (describe size and distance expected to travel):
All litter remains in place. After fire, litter moves and deposits in debris dams. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Slake test values collected from under grass canopy were scored from 4 to 6 with 85% of the samples at 5 and 6; samples collect from outside of canopy also scored from 4 to 6 with 75% of the samples at 5 and 6. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil surface horizon 0-3" depth was silt loam with a weak platy structure. Color 7.5 YR 3/2 moist. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Plant basal cover is well-dispersed across site (5-15% basal cover; tall grasses 50-80% foliar canopy cover) and dissipates overbank flood events resulting in sheet floods on the site 1-2" deep. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
No compaction. Soil penetrometer averaged 6 cm with a range of depths from 4-10 cm. -
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:
Tall grassesSub-dominant:
Sod-forming perennial midgrassesOther:
Perennial vining forbsAdditional:
Tall annual forbs fluctuate with rainfall -
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Very little mortality or decadence (<5%) at 4 years after fire. Decadence increases with time post-burn. -
Average percent litter cover (%) and depth ( in):
Expect a marked reduction in litter cover after fire. Litter cover recovers within one year. -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
3065 lbs/ac. in a below average year; 4105 lbs/ac. in an average year; 7250 lbs/ac. in an above average year. -
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:
Johnson grass, hoary cress, bermudagrass, mesquite, burrobrush -
Perennial plant reproductive capability:
Not impaired.
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