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Ecological site R038XB202AZ

Clayey Upland 16-20" p.z.

Accessed: 11/21/2024

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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.

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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): 038X–Mogollon Transition South

AZ 38.2 - Interior Chaparral-Woodlands

Elevations range from 4000 to 5500 feet and precipitation averages 16 to 20 inches per year. Vegetation includes turbinella oak, Wright silktassel, hollyleaf buckthorn, desert buckbrush, one-seed juniper, alligator juniper, pinyon, algerita, sugar sumac, prairie junegrass, blue grama, curly mesquite, bottlebrush squirreltail, muttongrass, cane beardgrass, plains lovegrass and bullgrass. The soil temperature regime ranges from thermic to mesic and the soil moisture regime is aridic ustic. This unit occurs within the Transition Zone Physiographic Province and is characterized by canyons and structural troughs or valleys. Igneous, metamorphic and sedimentary rock classes occur on rough mountainous terrain in association with less extensive sediment filled valleys exhibiting little integrated drainage.

Classification relationships

Similar site to TES (Terrestrial Ecosystem Sites) map unit no's. 463, 471 and 472 on the Prescott National Forest.

Associated sites

R038XB203AZ	Clay Loam Upland 16-20" p.z.
R038XB209AZ	Loamy Upland 16-20" p.z.
R038XB215AZ	Clayey Hills 16-20" p.z.

R038XB203AZ

Clay Loam Upland 16-20" p.z.

R038XB209AZ

Loamy Upland 16-20" p.z.

R038XB215AZ

Clayey Hills 16-20" p.z.

Similar sites

R038XA102AZ	Clayey Upland 12-16" p.z.
R041XC304AZ	Clayey Upland 12-16" p.z.

R038XA102AZ

Clayey Upland 12-16" p.z.

R041XC304AZ

Clayey Upland 12-16" p.z.

Table 1. Dominant plant species

Tree	Not specified
Shrub	Not specified
Herbaceous	(1) Pleuraphis mutica (2) Koeleria macrantha

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Physiographic features

This site occurs in the mid to upper elevations of the Mogollon Transition zone south of the Rim in central Arizona.
This site is in an upland position. It neither benefits significantly from run-in moisture nor suffers from excess runoff. Slopes range from 0 to 8 percent on valley fill plains, basalt flows and mesa tops.

Table 2. Representative physiographic features

Landforms	(1) Alluvial flat (2) Lava flow (3) Mesa
Elevation	1,341 – 1,707 m
Slope	0 – 8%
Aspect	Aspect is not a significant factor

Climatic features

Precipitation in this common resource area averages 16 to 20 inches annually. The winter-summer rainfall ratio ranges from about 60/40% in the western part of the area to 45/55% in the eastern part. Summer rains fall July through September; and are from high-intensity convective thunderstorms. This moisture originates primarily from the Gulf of Mexico, but can come from the remnants of Pacific hurricanes in September. Winter moisture is frontal, originates in the north Pacific, and falls as rain or snow in widespread storms of low intensity and long duration. Snowfall ranges from 5 to 35 inches per year and can occur from November through April. Snow seldom persists for more than a week. May and June are the driest months of the year. Humidity is generally low all year. Average annual air temperatures range from 51 to 60 degrees F
(thermic temperature regime). Daytime temps in the summer are commonly in the low 90's. Freezing temperatures are common from October through April. The actual precipitation, avaliable moisture and temperature varies, depending on, region, elevation, rain shadow effect and aspect.

Table 3. Representative climatic features

Frost-free period (average)	180 days
Freeze-free period (average)	240 days
Precipitation total (average)	508 mm

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Figure 2. Monthly precipitation range

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Line

Figure 3. Monthly average minimum and maximum temperature

Soil features

These soils are moderately deep to deep (30 to 60 inches), clayey throughout, and well drained. They are formed in alluvium from basalt, andesite and related volcanic tuffs and ash. The surface textures are clay and silty clay except for small areas with silty clayloam textures. They have vertic properties and crack and churn with wetting and drying. The effective rooting depth is 30 to 60 inches, plus. Runoff is slow on dry soils due to cracks and holes, but is moderate to high on moist soils. The erosion hazard is slight unless heavy traffic causes trailing and compaction.

Soil series mapped include: SSA639 Black Hills-Sedona Area MU 417 Biplane and SSA675 San Carlos IR Area MU's 008 Ashcreek, 023 & 025 Cherrycow clay and 024, 025, 026, 45 & 81 Cloverdale clay.

Table 4. Representative soil features

Parent material	(1) Alluvium – basalt
Surface texture	(1) Cobbly clay (2) Gravelly silty clay (3) Silty clay loam
Family particle size	(1) Clayey
Drainage class	Well drained to moderately well drained
Permeability class	Moderately rapid to slow
Soil depth	76 – 152 cm
Surface fragment cover <=3"	5 – 20%
Surface fragment cover >3"	1 – 10%
Available water capacity (0-101.6cm)	9.14 – 18.29 cm
Calcium carbonate equivalent (0-101.6cm)	1 – 15%
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 – 8.2
Subsurface fragment volume <=3" (Depth not specified)	0 – 10%
Subsurface fragment volume >3" (Depth not specified)	0 – 5%

Ecological dynamics

The native plant community is a tobosa grassland (canopy cover of 50 to 70%) with an important component of cool season grasses that fluctuate with climate. Cool and warm season annual grasses and forbs are well represented in the flora. Perennial forbs are an important group also. Periodic wildfires occured every 10 to 15 years; June through August, and controlled shrubs and succulents invading from adjacent, shallow soil, areas. In the absence of fire for long periods of time; shrubs, trees and cacti can dominate the site. The interactions of drought, fire and grazing can result in a loss of tobosa cover. If tobosa canopy is reduced to less than 5% cover and is patchy in distribution; it may not be able to re-colonize large areas. In these situations annuals, both native and non-native can dominate the plant community. Non-native annuals can, over time, diminish the soil seed-bank of native annual species.

State and transition model

Custom diagram

Standard diagram

Figure 4. Clayey Upland 16-20" pz. state and transition

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
Tobosa Grassland State

Community 1.1
Tobosa Grassland Plant Community

Figure 5. Clayey Upland 16-20" pz. photos

The historic, native, plant community is a grassland dominated by tobosa grass with lesser amounts of vine mesquite, blue grama, sideoats grama, black grama and curley mesquite. Prairie junegrass, western wheatgrass, muttongrass and bottlebrush squirreltail are an important group of cool season grasses in the plant community, but can diminish to low levels after severe winter - spring drought. A rich flora of native annual forbs and grasses, of both the winter and summer seasons, exist in the plant community. Periodic, naturally occuring, wildfires were important in maintaining the potential plant community.

Figure 6. 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	841	1037	1429
Tree	157	204	267
Shrub/Vine	112	146	191
Forb	45	58	76
Total	1155	1445	1963

Table 6. Ground cover

Tree foliar cover	0%
Shrub/vine/liana foliar cover	0-5%
Grass/grasslike foliar cover	12-18%
Forb foliar cover	0-2%
Non-vascular plants	0-1%
Biological crusts	0-5%
Litter	35-55%
Surface fragments >0.25" and <=3"	0-15%
Surface fragments >3"	0-10%
Bedrock	0%
Water	0%
Bare ground	15-25%

Table 7. Canopy structure (% cover)

Height Above Ground (m)	Tree	Shrub/Vine	Grass/ Grasslike	Forb
<0.15	–	–	0-5%	1-5%
>0.15 <= 0.3	–	0-2%	2-15%	1-10%
>0.3 <= 0.6	–	0-2%	40-70%	1-2%
>0.6 <= 1.4	–	0-2%	–	–
>1.4 <= 4	0-2%	0-2%	–	–
>4 <= 12	0-2%	–	–	–
>12 <= 24	–	–	–	–
>24 <= 37	–	–	–	–
>37	–	–	–	–

Figure 7. Plant community growth curve (percent production by month). AZ3812, 38.2 16-20" p.z. all sites. Growth begins in the spring and continues into the summer and 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	5	5	15	10	10	15	20	10	5	5	0

State 2
Annual Dominated State

Community 2.1
Annual Forb and Grass Plant Community

Tobosa canopy cover is reduced due to the interactions of drought, grazing and / or fire. Native and non-native annual forbs and grasses dominate the plant community. Tobosa canopy cover is less than 5% and patchy in distribution. Tobosa may not be able to re-colonize large areas because of very poor seed production and little or no seeds in the seed-bank. Vertic soil properties maintain good, surface, soil tilth and good infiltration rates when soils are dry. Plant production is high, even with the lack of perennial grass cover, due to soil cracking and churning.

State 3
Shrub and Annual Dominated State

Community 3.1
Shrub and Annual Plant Community

Shrubs like; mesquite, wait a bit mimosa and catclaw acacia; succulents like; prickly pear, cholla and yucca, and trees like one-seed juniper, alligator juniper and redberry juniper, invade from adjacent, shallow soil, areas, to dominate the site in the absence of fire. Native and non-native annual forbs and grasses dominate the understory. In "El Nino" years, herbaceous fuels can be sufficient to carry fire through the heavy canopy of shrubs. The major woody shrubs are, however, fire resistant once established. Tobosa cannot re-colonize large areas with low canopy cover levels and patchy distribution.

State 4
Exotic Invaded State

Community 4.1
Exotic Forb and Grass Plant Community

Non-native annual grasses and forbs like; red brome, cheatgrass, kochia, tumble pigweed, russian thistle, tumble mustard, yellow starthistle, wild oats and filaree, can invade and dominate areas of the site with very low tobosa cover. Perennial forbs like russian knapweed and leafy spurge could invade and, perhaps, dominate this site. These species can, over time, reduce the seed-bank of native annual grasses and forbs. Their presence can increase the fire frequency (of man made fires) especially where roads and urban areas are adjacent to areas of the site.

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	Grasses			112–336
	tobosagrass	PLMU3	Pleuraphis mutica	112–336	–
2	Cool Season Grasses			364–729
	western wheatgrass	PASM	Pascopyrum smithii	219–364	–
	muttongrass	POFE	Poa fendleriana	73–219	–
	squirreltail	ELELE	Elymus elymoides ssp. elymoides	73–146	–
3	misc. perennial grasses			11–112
	vine mesquite	PAOB	Panicum obtusum	0–112	–
	cane bluestem	BOBA3	Bothriochloa barbinodis	0–56	–
	sideoats grama	BOCU	Bouteloua curtipendula	0–56	–
	blue grama	BOGR2	Bouteloua gracilis	0–56	–
	curly-mesquite	HIBE	Hilaria belangeri	0–56	–
	black grama	BOER4	Bouteloua eriopoda	0–28	–
	threeawn	ARIST	Aristida	0–28	–
	common wolfstail	LYPH	Lycurus phleoides	0–17	–
	creeping muhly	MURE	Muhlenbergia repens	0–11	–
	slender muhly	MUTE4	Muhlenbergia tenuifolia	0–11	–
4	annual grasses			28–448
	little barley	HOPU	Hordeum pusillum	11–336	–
	Mexican sprangletop	LEFUU	Leptochloa fusca ssp. uninervia	11–224	–
	mucronate sprangeltop	LEPAB	Leptochloa panicea ssp. brachiata	11–224	–
	Mexican panicgrass	PAHI5	Panicum hirticaule	0–224	–
	prairie threeawn	AROL	Aristida oligantha	0–112	–
	needle grama	BOAR	Bouteloua aristidoides	0–56	–
	tufted lovegrass	ERPE	Eragrostis pectinacea	0–56	–
	desert lovegrass	ERPEM	Eragrostis pectinacea var. miserrima	0–56	–
	small fescue	VUMI	Vulpia microstachys	0–56	–
	Eastwood fescue	VUMIC	Vulpia microstachys var. ciliata	0–56	–
	sixweeks fescue	VUOC	Vulpia octoflora	0–56	–
	sticky sprangletop	LEVI5	Leptochloa viscida	0–56	–
	sixweeks threeawn	ARAD	Aristida adscensionis	0–56	–
	feather fingergrass	CHVI4	Chloris virgata	0–56	–
	witchgrass	PACA6	Panicum capillare	0–56	–
	canyon cupgrass	ERLE7	Eriochloa lemmonii	0–28	–
	delicate muhly	MUFR	Muhlenbergia fragilis	0–28	–
	littleseed muhly	MUMI	Muhlenbergia microsperma	0–28	–
	Bigelow's bluegrass	POBI	Poa bigelovii	0–28	–
	sixweeks grama	BOBA2	Bouteloua barbata	0–28	–
	Arizona brome	BRAR4	Bromus arizonicus	0–28	–
	Arizona signalgrass	URAR	Urochloa arizonica	0–17	–
Forb
5	perennial forbs			17–112
	largeflower onion	ALMA4	Allium macropetalum	1–56	–
	Lewis flax	LILE3	Linum lewisii	0–56	–
	desert globemallow	SPAM2	Sphaeralcea ambigua	0–28	–
	copper globemallow	SPAN3	Sphaeralcea angustifolia	0–28	–
	brownplume wirelettuce	STPA4	Stephanomeria pauciflora	0–28	–
	weakleaf bur ragweed	AMCO3	Ambrosia confertiflora	1–28	–
	bluedicks	DICA14	Dichelostemma capitatum	1–28	–
	Indian rushpea	HOGL2	Hoffmannseggia glauca	1–28	–
	leastdaisy	CHAET2	Chaetopappa	0–17	–
	Greene's bird's-foot trefoil	LOGR4	Lotus greenei	0–17	–
	Wright's deervetch	LOWR	Lotus wrightii	0–17	–
	vetch	VICIA	Vicia	0–11	–
	rose heath	CHER2	Chaetopappa ericoides	0–11	–
	Texas bindweed	COEQ	Convolvulus equitans	0–11	–
	onion	ALLIU	Allium	0–11	–
	Forb, perennial	2FP	Forb, perennial	0–11	–
	scarlet spiderling	BOCO	Boerhavia coccinea	0–11	–
	ragwort	SENEC	Senecio	0–11	–
	sego lily	CANU3	Calochortus nuttallii	0–6	–
	brownfoot	ACWR5	Acourtia wrightii	0–6	–
	tuber anemone	ANTU	Anemone tuberosa	0–6	–
	Braun's rockcress	ARPE3	Arabis perstellata	0–6	–
	southwestern mock vervain	GLGO	Glandularia gooddingii	0–6	–
	desert larkspur	DEPA	Delphinium parishii	0–6	–
	Parry's beardtongue	PEPA24	Penstemon parryi	0–6	–
	orange fameflower	PHAU13	Phemeranthus aurantiacus	0–6	–
	canaigre dock	RUHY	Rumex hymenosepalus	0–6	–
	twinleaf senna	SEBA3	Senna bauhinioides	0–6	–
6	annual forbs			28–560
	common sunflower	HEAN3	Helianthus annuus	0–112	–
	longleaf false goldeneye	HELOA2	Heliomeris longifolia var. annua	0–56	–
	crestrib morning-glory	IPCO2	Ipomoea costellata	1–56	–
	spreading fleabane	ERDI4	Erigeron divergens	0–56	–
	Arizona popcornflower	PLAR	Plagiobothrys arizonicus	1–56	–
	creamcups	PLCA5	Platystemon californicus	0–56	–
	Forb, annual	2FA	Forb, annual	0–56	–
	aster	ASTER	Aster	0–56	–
	carelessweed	AMPA	Amaranthus palmeri	0–56	–
	New Mexico thistle	CINE	Cirsium neomexicanum	2–56	–
	goldeneye	VIGUI	Viguiera	0–56	–
	milkvetch	ASTRA	Astragalus	0–28	–
	Coulter's spiderling	BOCO2	Boerhavia coulteri	0–28	–
	lambsquarters	CHAL7	Chenopodium album	0–28	–
	aridland goosefoot	CHDE	Chenopodium desiccatum	0–28	–
	desert Indianwheat	PLOV	Plantago ovata	0–28	–
	woolly plantain	PLPA2	Plantago patagonica	0–28	–
	New Mexico plumeseed	RANE	Rafinesquia neomexicana	0–28	–
	miniature woollystar	ERDI2	Eriastrum diffusum	0–28	–
	miniature lupine	LUBI	Lupinus bicolor	0–28	–
	Coulter's lupine	LUSP2	Lupinus sparsiflorus	0–28	–
	hollowleaf annual lupine	LUSU3	Lupinus succulentus	0–28	–
	tanseyleaf tansyaster	MATA2	Machaeranthera tanacetifolia	0–28	–
	manybristle chinchweed	PEPA2	Pectis papposa	0–28	–
	California poppy	ESCAM	Eschscholzia californica ssp. mexicana	0–28	–
	western tansymustard	DEPI	Descurainia pinnata	0–28	–
	California goldfields	LACA7	Lasthenia californica	0–28	–
	camphorweed	HESU3	Heterotheca subaxillaris	0–28	–
	Thurber's pepperweed	LETH2	Lepidium thurberi	0–28	–
	foothill deervetch	LOHU2	Lotus humistratus	0–28	–
	coastal bird's-foot trefoil	LOSA	Lotus salsuginosus	0–28	–
	trefoil	LOTUS	Lotus	0–28	–
	Arizona lupine	LUAR4	Lupinus arizonicus	0–17	–
	Goodding's bladderpod	LEGO2	Lesquerella gooddingii	0–17	–
	shaggyfruit pepperweed	LELA	Lepidium lasiocarpum	0–17	–
	purslane	PORTU	Portulaca	0–17	–
	desert unicorn-plant	PRAL4	Proboscidea althaeifolia	0–17	–
	doubleclaw	PRPA2	Proboscidea parviflora	0–17	–
	sand fringepod	THCU	Thysanocarpus curvipes	0–17	–
	sleepy silene	SIAN2	Silene antirrhina	0–11	–
	ragwort	SENEC	Senecio	0–11	–
	phacelia	PHACE	Phacelia	0–11	–
	green carpetweed	MOVE	Mollugo verticillata	0–11	–
	evening primrose	OENOT	Oenothera	0–11	–
	grassleaf lettuce	LAGRA	Lactuca graminifolia var. arizonica	0–11	–
	sanddune wallflower	ERCA14	Erysimum capitatum	0–11	–
	American wild carrot	DAPU3	Daucus pusillus	0–11	–
	spurge	EUPHO	Euphorbia	0–11	–
	New Mexico fleabane	ERNE3	Erigeron neomexicanus	0–11	–
	sorrel buckwheat	ERPO4	Eriogonum polycladon	0–11	–
	bristly fiddleneck	AMTE3	Amsinckia tessellata	0–11	–
	annual agoseris	AGHE2	Agoseris heterophylla	0–11	–
	scrambled eggs	COAU2	Corydalis aurea	0–6	–
	cryptantha	CRYPT	Cryptantha	0–6	–
	Florida pellitory	PAFL3	Parietaria floridana	0–6	–
	spreading fanpetals	SIAB	Sida abutifolia	0–6	–
Shrub/Vine
7	shrubs			0–112
	catclaw acacia	ACGR	Acacia greggii	0–28	–
	catclaw mimosa	MIACB	Mimosa aculeaticarpa var. biuncifera	0–28	–
	velvet mesquite	PRVE	Prosopis velutina	0–28	–
	Sonoran scrub oak	QUTU2	Quercus turbinella	0–28	–
	skunkbush sumac	RHTR	Rhus trilobata	0–17	–
	pale desert-thorn	LYPA	Lycium pallidum	0–17	–
	algerita	MATR3	Mahonia trifoliolata	0–17	–
	fourwing saltbush	ATCA2	Atriplex canescens	0–17	–
	sugarberry	CELA	Celtis laevigata	0–11	–
8	half shrubs			0–56
	bastardsage	ERWR	Eriogonum wrightii	0–56	–
	broom snakeweed	GUSA2	Gutierrezia sarothrae	0–28	–
	yerba de pasmo	BAPT	Baccharis pteronioides	0–28	–
	Coville's bundleflower	DECO4	Desmanthus covillei	0–17	–
	prairie acacia	ACAN	Acacia angustissima	0–17	–
9	succulents			0–56
	walkingstick cactus	CYSP8	Cylindropuntia spinosior	0–28	–
	sacahuista	NOMI	Nolina microcarpa	0–28	–
	cactus apple	OPEN3	Opuntia engelmannii	0–28	–
	banana yucca	YUBA	Yucca baccata	0–17	–
	soaptree yucca	YUEL	Yucca elata	0–17	–
	Whipple cholla	CYWH	Cylindropuntia whipplei	0–17	–
	goldenflower century plant	AGCH2	Agave chrysantha	0–17	–
	chaparral yucca	HEWH	Hesperoyucca whipplei	0–11	–
	common sotol	DAWH2	Dasylirion wheeleri	0–11	–
	spinystar	ESVI2	Escobaria vivipara	0–6	–
Tree
10	evergreen trees			0–28
	redberry juniper	JUCO11	Juniperus coahuilensis	0–28	–
	alligator juniper	JUDE2	Juniperus deppeana	0–28	–
	oneseed juniper	JUMO	Juniperus monosperma	0–28	–
	Rocky Mountain juniper	JUSC2	Juniperus scopulorum	0–17	–

Interpretations

Animal community

This site is suitable for grazing year round and is easily traversed by all classes of livestock. the site is susceptible to erosion only in overgrazed areas, old roads, cattle trails and concentration areas like bed grounds, water-lots and salt grounds.
The site has good habitat diversity for grassland wildlife species. Where it is adjacent to hill sites with tree species or chaparral; it is a foraging area for elk.

Hydrological functions

Due to severe cracking and churning (producing rough and porous surfaces), this site has very high initial infiltration rates. It produces runoff only when soils are moist.

Recreational uses

Hunting, camping, hiking, horseback riding, and backpacking.

Wood products

None

Other products

There is some native harvest of foods like wild onion, sunflower and thistle.

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)	Dave Womack, Emilio Carrillo
Contact for lead author	USDA NRCS Globe Soil Survey Office
Date	05/09/2008
Approved by	Byron Lambeth
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
None present on this site.
Presence of water flow patterns:
Water flow patterns are 1-2 feet in length and broken by microtopography created by cracking and churning of the soil and frequent perennial grass plant bases.
Number and height of erosional pedestals or terracettes:
None present on this site.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
15-25%
Number of gullies and erosion associated with gullies:
None present on this site.
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):
Herbaceous litter is dominant on this site and moves 1-2 feet until it encounters microtopographic lows or perennial grass plant bases.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface stability values range from 5-6.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Weak granular to moderate fine subangular blocky. 7.5YR 4/3 dry, 7.5YR 3/3 moist. Thickness to 3 inches.
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Warm season grasses dominate the plant community and contribute the most towards infiltration. High shrink-swell soil properties are also significant to infiltration. Plants are well distributed across site with average spacing of 1 foot between perennial plants.
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. Freeze-thaw action reduces the incidence of compaction.
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:
tobosa >> cool season perennial grasses > warm season perennial grasses

Sub-dominant:
annual grasses = annual forbs > perennial forbs (in el nino years annual grassses and forbs >= other warm season perennial grasses

Other:
shrubs = half shrubs = succulents

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Some. Approximately 30-40% of basal cover is lost in prolonged drought.
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
From ecological site description average annual production is: 750 lbs/ac(drought), 1725 lbs/ac(normal year), 2600 lbs/ac (wet 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:
tumble mustard, filaree. mesquite, juniper, wait-a-bit mimosa, catclaw acacia, cane cholla, prickley pear, wild oats, red brome, cheatgrass, yellow starthistle, Russian knapweed, leafy spurge
Perennial plant reproductive capability:
Not affected even during prolonged regional drought.

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Natural ResourcesConservation Service

Ecological site R038XB202AZ

Clayey Upland 16-20" p.z.

Accessed: 11/21/2024

General information

Figure 1. Mapped extent

MLRA notes

Classification relationships

Associated sites

Similar sites

Table 1. Dominant plant species

Ecosystem states

State 1 submodel, plant communities

State 2 submodel, plant communities

State 3 submodel, plant communities

State 4 submodel, plant communities

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