|
|
UNITED STATES
DEPARTMENT OF AGRICULTURE
NATURAL RESOURCES CONSERVATION SERVICE
ECOLOGICAL SITE DESCRIPTION
|
ECOLOGICAL SITE CHARACTERISTICS
|
|
Site Type: Rangeland
Site Name: Sandy Loam 12-16" p.z. Deep
/ eriogonum wrightii / bouteloua curtipendula - digitaria californica
( / bastardsage / sideoats grama - Arizona cottontop)
Site ID: R041XC318AZ
Major Land Resource Area: 041 - Southeastern Arizona Basin and Range
|
 |
|
|
|
Physiographic Features
|
This site occurs in the middle elevations of the Madrean Basin and Range province in southeastern Arizona. This site occurs on fan terraces and stream terraces. It is always in an upland position. Slopes are mainly 1-3%, but may range as high as 8%.
|
| Land Form: |
(1) |
Terrace |
|
(2) |
Fan piedmont |
|
(3) |
Plain |
|
Minimum |
Maximum |
| Elevation (feet): |
3300 |
5000 |
| Slope (percent): |
1 |
8 |
| Water Table Depth (inches): |
|
|
| Flooding: |
|
|
| Frequency: |
None |
None |
| Duration: |
None |
None |
| Ponding: |
|
|
| Depth (inches): |
|
|
| Frequency: |
None |
None |
| Duration: |
None |
None |
| Runoff Class: |
Low |
Low |
| Aspect: |
No Influence on this site
|
|
|
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.
|
|
Minimum |
Maximum |
| Frost-free period (days): |
170 |
220 |
| Freeze-free period (days): |
0 |
0 |
| Mean annual precipitation (inches): |
12.0 |
16.0 |
|
| Monthly precipitation (inches) and temperature (°F): |
|
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| Precip. Min. |
0.76 |
0.67 |
0.5 |
0.29 |
0.17 |
0.5 |
2.44 |
2.61 |
1.63 |
0.9 |
0.53 |
0.87 |
|
| Precip. Max. |
1.1 |
0.97 |
0.5 |
0.3 |
0.24 |
0.52 |
3.86 |
3.46 |
1.72 |
0.88 |
0.74 |
1.08 |
|
| Temp. Min. |
46.3 |
48.8 |
54.0 |
60.0 |
67.5 |
76.8 |
77.3 |
75.2 |
72.1 |
64.1 |
53.5 |
47.1 |
|
| Temp. Max. |
46.8 |
49.7 |
54.6 |
61.7 |
68.1 |
77.1 |
80.7 |
78.6 |
73.9 |
65.1 |
54.1 |
48.3 |
|
|
| Climate Stations: |
(1) 020309, Apache Powder Co.. Period of record 1923 - 1990 |
|
(2) 022659, Douglas. Period of record 1948 - 2004 |
|
(3) 023120, Fort Huachuca. Period of record 1900 - 1981 |
|
(4) 027530, San Manuel. Period of record 1954 - 2004 |
|
(5) 028619, Tombstone. Period of record 1893 - 2004 |
|
|
|
Influencing Water Features
|
There are no water features associated with this site.
|
| Wetland Description: |
System |
Subsystem |
Class |
|
|
|
|
Representative Soil Features
|
These are deep soils which have formed in recent sandy alluvium, usually, of granitic origin. They are sandy loam throughout at least to moderate depths (40 inches). Surface textures range from loamy sand to gravelly sandyloam. Soil surfaces are thick and dark colored. Plant-soil moisture relationships are good. Soil series mapped on this site include, Combate, Diaspar, Mallet, Altar and Swisshelm.
|
Predominant Parent Materials:
Kind: Alluvium
Origin: Granite
|
| Surface Texture: |
(1) Loamy sand |
|
(2) Sandy loam |
|
(3) Gravelly Sandy loam |
|
Subsurface Texture Group: Loamy
|
|
Minimum |
Maximum |
| Surface Fragments <=3" (% Cover): |
1 |
20 |
| Surface Fragments > 3" (% Cover): |
0 |
2 |
| Subsurface Fragments <=3" (% Volume): |
2 |
20 |
| Subsurface Fragments > 3" (% Volume): |
0 |
2 |
|
| Drainage Class: Well drained
To Well drained
|
| Permeability Class: Moderately rapid
To Rapid
|
|
Minimum |
Maximum |
| Depth (inches): |
40 |
60 |
| Electrical Conductivity (mmhos/cm): |
0 |
2 |
| Sodium Absorption Ratio: |
0 |
2 |
| Calcium Carbonate Equivalent (percent): |
0 |
5 |
| Soil Reaction (1:1 Water): |
6.6 |
8.4 |
| Soil Reaction (0.01M CaCl2): |
|
|
| Available Water Capacity (inches): |
4.8 |
7.8 |
|
|
|
Plant Communities
|
| Ecological Dynamics of the Site |
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 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 the group. Divide the resulting total by the total normal year production shown in the plant community description. If rainfall has been significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
|
Sandy Loam Deep 12-16" p.z.
|
| Historic Climax Plant Community |
The potential plant community on this site is dominated by warm season perennial grasses. The major perennial grass species on the site tend to be well dispersed throughout the plant community. Several species of half-shrubs are well represented in the plant community. The aspect is grassland with occasional clumps of desert hackberry, catclaw acacia or mesquite.
With continuous heavy grazing, palatable perennial grasses are removed from the potential plant community and species such as Rothrock grama, mesa threeawn, and spidergrass increase. In areas where burroweed dominates the plant community the potential production of perennial mid-grasses is equal to the present production of burroweed once it is removed from the plant community. Even with low plant cover, these soils produce very little runoff and have very low erosion rates. Some soils are sandy textured but have enough coarse fragments that they are not subject to wind erosion. Naturally occurring wildfires (June through August) were important in the development of the potential plant community, and helped maintain a grassland aspect. Hydrologic relationships are good with very little runoff in most years due to coarse textured soils, high plant and litter cover and low soil bulk densities.
|
Sandy Loam Deep 12-16" pz.
|
|
| Historic Climax Plant Community Plant Species Composition: |
|
|
| Annual Production by Plant Type: |
|
Annual Production (lbs/AC) |
| Plant Type |
Low |
Representative Value |
High |
| Forb |
30 |
50 |
250 |
| Grass/Grasslike |
435 |
850 |
1330 |
| Shrub/Vine |
56 |
100 |
260 |
| Tree |
0 |
5 |
15 |
Total: |
521 |
1005 |
1855 |
|
| Structure and Cover: |
Soil Surface Cover (%)
| Basal Cover |
Non-Vascular Plants |
Biological Crust |
Litter |
Surface Fragments > 1/4 & <= 3" |
Surface Fragments > 3" |
Bedrock |
Water |
Bare Ground |
| Grass/ Grasslike |
Forb |
Shrub/ Vine |
Tree |
|
6 to 15
|
0 to 1
|
0 to 1
|
0 to 1
|
0 to 1
|
0 to 5
|
30 to 75
|
5 to 20
|
0 to 2
|
0 to 0
|
0 to 0
|
10 to 25
|
|
| |
Structure of Canopy Cover (%)
|
Grasses/Grasslike |
Forbs |
Shrubs/Vines |
Trees |
| <=0.5 feet |
0 to 10
|
0 to 5
|
0 to 5
|
|
| > 0.5 - < 1 feet |
10 to 20
|
1 to 5
|
2 to 10
|
|
| < 1 - >= 2 feet |
20 to 40
|
0 to 5
|
0 to 10
|
|
| > 2 - < 4.5 feet |
0 to 10
|
|
0 to 1
|
|
| < 4.5 - >= 13 feet |
|
|
0 to 1
|
0 to 1
|
|
| |
|
Plant Growth Curve:
Growth Curve Number: AZ4134
Growth Curve Name: 41.3 12-16" p.z. other sites
Growth Curve Description: Growth begins in the spring, semi-dormancy occurs during the May through June drought, most growth occurs during the summer rains.
| Percent Production by Month |
| Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| 0 |
0 |
5 |
10 |
0 |
0 |
30 |
35 |
15 |
5 |
0 |
0 |
|
| Mesquite, native grass |
Mesquite increases in the absence of fire for long periods of time. Native perennial grasses maintain dominance, with good grazing management, and mesquite canopy levels up to 10%. Burroweed fluctuates in the plant community with climate, but never becomes dominant. Cholla and prickly pear can cycle through the plant community. Some soil compaction has occurred due to livestock traffic, but hydrologic relationships have not been impaired.
|
Sandy Loam Deep 12-16" pz. Combate soils
|
|
| Mesquite, annual grass and forb state |
Mesquite is dominant with canopy levels of 10 to 15%. Native and non-native annual forbs and grasses, both cool and warm season, dominate the under-story. Burroweed and snakeweed cycle with climate, but are always important in the under-story. Native perennial grasses are gone due to the interactions of drought, fire and continuous heavy grazing. Usually, soil compaction and the loss of herbaceous cover have resulted in sheet, rill and gully erosion on the site. Hydrologic relationships have changed to increase the amount of runoff.
|
Sandy Loam Deep 12-16" pz. mesquite, annuals
|
|
| Mesquite, Lehmann lovegrass |
Mesquite has increased in the absence of fires for long periods of time to canopy levels of 10%. Lehmann lovegrass has invaded from seeded areas and is dominant in the under-story. Remnant native perennial grasses diminish over time. Native annual forbs and grasses diminish in the soil seed-bank over time. Fire may act to increase dominance of lehmann lovegrass at the expense of native perennial grasses, but may allow native annual species a chance to make seed and persist in the seed-bank. Some soil compaction has occurred due to livestock traffic, but hydrologic relationships have not been impaired.
|
Sandy Loam Deep 12-16" pz. Lehmann invasion
|
|
| Dense mesquite and other shrubs, succulents |
Mesquite continues to increase in the absence of fire up to canopy levels of 25%. Other shrubs and succulents like prickly pear and cholla, dominate the under-story. Remnant perennial grasses exist only in the protection of cacti and shrubs. Occasional fires may burn after extremely wet seasons, but mesquite is well established and sprouts back to a thorn-scrub stage. Soil compaction and reduced herbaceous cover has resulted in sheet, rill and gully erosion on the site. Hydrologic relationships have been impaired and runoff is increased.
|
Sandy Loam Deep 12-16" pz. dense mesquite, eroded
|
|
|
|
Ecological Site Interpretations
|
Animal Community:
The plant community on this site is suitable for grazing by all classes of cattle at any season. The summer green season for forage species is moderate due to coarse textured, somewhat droughty soils. Shallow rooted grasses are severely affected by drought on this site. Management should be designed to maintain deeper rooted mid-grasses on the site. The plant community on the site includes a variety of browse and many perennial forbs, providing good forage in the spring and fall. Herbaceous forage is deficient in protein in the winter.
Water developments are very important to wildlife species on this site. Being grassland, the site is home to a number of small herbivores and their predators. Larger wildlife species use the site mainly as a foraging area.
|
Plant Preference by Animal Kind:
| Animal Kind: Livestock Cattle |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| shortleaf baccharis |
Baccharis brachyphylla |
Leaves |
E |
E |
D |
D |
D |
D |
D |
D |
D |
E |
E |
E |
| sideoats grama |
Bouteloua curtipendula |
Leaves |
U |
U |
D |
D |
D |
P |
P |
P |
P |
P |
P |
U |
| black grama |
Bouteloua eriopoda |
Entire plant |
P |
P |
D |
D |
D |
E |
E |
E |
D |
D |
D |
P |
| Rothrock's grama |
Bouteloua rothrockii |
Leaves |
U |
U |
U |
U |
U |
P |
P |
P |
E |
E |
E |
U |
| fairyduster |
Calliandra eriophylla |
Leaves |
U |
U |
D |
D |
D |
U |
U |
U |
U |
U |
U |
U |
| Arizona cottontop |
Digitaria californica |
Leaves |
E |
E |
D |
D |
D |
P |
P |
P |
P |
P |
P |
E |
| bastardsage |
Eriogonum wrightii |
Leaves |
D |
D |
D |
P |
P |
D |
D |
D |
D |
D |
D |
D |
| bush muhly |
Muhlenbergia porteri |
Entire plant |
D |
D |
D |
D |
D |
E |
E |
U |
U |
D |
D |
D |
| spike dropseed |
Sporobolus contractus |
Leaves |
U |
U |
E |
E |
E |
D |
D |
D |
E |
E |
E |
U |
| Animal Kind: Desert Mule Deer |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| fourwing saltbush |
Atriplex canescens |
Leaves |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| spreading fleabane |
Erigeron divergens |
Leaves |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| bastardsage |
Eriogonum wrightii |
Leaves |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Desert mule deer Deer |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| candy barrelcactus |
Ferocactus wislizeni |
Fruits/Seeds |
N |
N |
N |
N |
N |
P |
P |
P |
D |
D |
D |
D |
| Animal Kind: Desert Mule Deer |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
|
Opuntia fulgida (Syn) |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
|
Opuntia versicolor (Syn) |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| desert globemallow |
Sphaeralcea ambigua |
Leaves |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| hairy fournwort |
Tetramerium nervosum |
Leaves |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Gambels Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| whitethorn acacia |
Acacia constricta |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Scaled Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| whitethorn acacia |
Acacia constricta |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| fourwing saltbush |
Atriplex canescens |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Gambels Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| fourwing saltbush |
Atriplex canescens |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| spreading fleabane |
Erigeron divergens |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Scaled Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| buckwheat |
Eriogonum |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| candy barrelcactus |
Ferocactus wislizeni |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Gambels Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| candy barrelcactus |
Ferocactus wislizeni |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| desert-thorn |
Lycium |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Scaled Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| desert-thorn |
Lycium |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
|
Opuntia fulgida (Syn) |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Gambels Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
|
Opuntia fulgida (Syn) |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
|
Opuntia versicolor (Syn) |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Scaled Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
|
Opuntia versicolor (Syn) |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| blue paloverde |
Parkinsonia florida |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Gambels Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| blue paloverde |
Parkinsonia florida |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Thurber's penstemon |
Penstemon thurberi |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Scaled Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| Thurber's penstemon |
Penstemon thurberi |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Animal Kind: Gambels Quail |
| Common Name |
Scientific Name |
Plant Part |
J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
| desert globemallow |
Sphaeralcea ambigua |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| soaptree yucca |
Yucca elata |
Fruits/Seeds |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
D |
| Legend:
P = Preferred
D = Desirable
U = Undesirable N = Not
consumed E = Emergency
T = Toxic X = Used,
but degree of utilization unknown
|
|
Hydrology Functions:
Hydrologic relationships are very good. Coarse textured soils, high plant and litter cover and low bulk densities result in very little runoff in most years.
|
Recreational Uses:
Hunting, hiking, horseback riding, photography
|
Wood Products:
Where mesquite has increased and grown to tree size, it provides both fuel-wood and posts.
|
Other Products:
|
Other Information:
|
|
|
Supporting Information
|
Associated Sites:
| Site Name |
Site ID |
Site Narrative |
| Granitic Hills 12-16" p.z. |
R041XC306AZ |
|
| Sandy Loam Upland 12-16" p.z. |
R041XC319AZ |
|
| Granitic Upland 12-16" p.z. |
R041XC322AZ |
|
|
Similar Sites:
| Site Name |
Site ID |
Site Narrative |
| Sandy Loam Upland 10-13" p.z. Deep |
R040XA117AZ |
|
| Sandy Loam Upland 16-20" p.z. |
R041XA110AZ |
|
|
State Correlation:
This site has been correlated with the following states:
AZ
|
Inventory Data References:
Six 417's are from Enclosure # 22 on the Santa Rita Experimental Range.
|
Other Inventory Data References:
| Data Source |
Number of Records |
Sample Period |
State |
County |
| Arizona Range 0ne |
21 |
|
Arizona |
Cochise |
| Arizona Range One |
34 |
|
Arizona |
Pima |
|
Type Locality:
| State: |
AZ |
| County: |
Cochise |
| Township: |
21S |
| Range: |
20E |
| Section: |
4 |
| General Legal Description: |
Fort Huachuca - South Range |
| Universal Transverse Mercator (UTM) system: |
|
| |
|
| State: |
AZ |
| County: |
Pima |
| Township: |
18S |
| Range: |
8E |
| Section: |
9 |
| General Legal Description: |
Anvil Ranch - Redondo Camp |
| Universal Transverse Mercator (UTM) system: |
|
| |
|
| State: |
AZ |
| County: |
Pima |
| Township: |
21S |
| Range: |
8E |
| Section: |
17 |
| General Legal Description: |
Buenos Aires NWR - Bailey Wash terrace |
| Universal Transverse Mercator (UTM) system: |
|
| |
|
| State: |
AZ |
| County: |
Pima |
| Township: |
18S |
| Range: |
15E |
| Section: |
16 |
| General Legal Description: |
Enclosure # 22 and Eriopoda enclosures on the Santa Rita Experimental Range. |
| Universal Transverse Mercator (UTM) system: |
|
| |
|
|
Relationship to Other Established Classifications:
|
Other References:
|
Site Description Approval:
|
| Author |
Date |
Approval |
Date |
| Dan Robinett |
3/29/2005 |
Steve Barker |
6/22/2005 |
|
Site Description Revision Approval:
|
| Author |
Date |
Approval |
Date |
| Steve Barker |
1/1/1993 |
unknown |
1/1/1993 |
| unknown |
1/1/1992 |
unknown |
1/1/1992 |
| Dan Robinett |
3/1/1988 |
Keith Wadman |
3/1/1988 |
| unknown |
1/1/1987 |
unknown |
1/1/1987 |
|
|
|
|
Reference Sheet
Author(s)/participant(s):
Dave Womack
Contact for lead author:
NRCS Tucson Area Office
Date:
2/8/2005
MLRA:
041X
Ecological Site:
Sandy Loam 12-16" p.z. Deep
R041XC318AZ
This must be verified based on soils and climate (see
Ecological Site Description). Current plant community cannot be used to
identify the ecological site.
Composition (indicators 10 and 12) based on:
X
Annual Production,
Foliar Cover,
Biomass
Indicators. For each indicator, describe the potential for the site. Where
possible, (1) use numbers, (2) include expected range of values for above- and below-average years
for each community and natural disturbance regimes within the reference state, when
appropriate and (3) cite data. Continue descriptions on separate sheet.
|
| 1. |
Number and extent of rills: None present on this site. |
|
| 2. |
Presence of water flow patterns: Water flow paths occupy 10-15% of the area; short (3-5 feet) in length and discontinuous. |
|
| 3. |
Number and height of erosional pedestals or terracettes: Pedestals are infrequent on long-lived perennial grasses. Approximately 10% of perennial grass plants have pedestals no more than 1 inch above surrounding soil surface. Black grama dominated areas have formed terracettes 2-5 feet apart with a 1-inch elevation difference from above to below the terracette. Bunchgrass dominated areas have formed terracettes 10-15 feet apart with a 1-inch elevation difference from above to below the terracette. |
|
| 4. |
Bare ground from Ecological Site Description or other studies (rock, litter, standing dead,
lichen, moss, plant canopy are not bare ground): Estimated in 20, 9.6 ft square frames at 22%. Note: this is following several years of regional drought. |
|
| 5. |
Number of gullies and erosion associated with gullies: None present on this site. |
|
| 6. |
Extent of wind scoured, blowouts and/or depositional areas: None present on this site. |
|
| 7. |
Amount of litter movement (describe size and distance expected to travel): All iltter size classes are staying in pace and mask water flow patterns. |
|
| 8. |
Soil surface (top few mm) resistance to erosion (stability values are averages -
most sites will show a range of values): No slake test done. Expect ratings of 4-6 under shrubs and grass canopies and in openings. |
|
| 9. |
Soil surface structure and SOM content (include type and strength of structure, and A-horizon color
and thickness): Weak granular; color is 10YR3/2 Dry, 10YR2/2 Moist; thickness to 10+ inches. Lab data from Combate soil series from SRER soil inventory was around 2-3% organic carbon. |
|
| 10. |
Effect on plant community composition (relative proportion of different functional groups) and
spatial distribution on infiltration and runoff: Cover estimated in 20, 9.6 ft square frames: Canopy 31%, basal 6%, litter 76%, and gravel 5%. 75-80% of canopy cover is perennial grasses and 5-10% is trees and shrubs. Cover is well dispersed throughout the site. |
|
| 11. |
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. Penetrometer tests with weight drop distance from top of weight to top of impact ring = 2.24 feet were: average = 3.55 inches, sd = 0.59 inches. Tests outside enclosure on SRER were: average = 1.84, s.d. = 0.22, tests off SRER to east of Exclosure 22 were: average = 1.35m s,d, = 0.24. |
|
| 12. |
Functional/Structural Groups (list in order of descending dominance by above-ground weight using
symbols: >>, >, = to indicate much greater than, greater than, and equal to) with dominants and
sub-dominants and "others" on separate lines:
Dominant: Perennial mid-grasses (tanglehead, sideoats grama, bush muhly, black grama) > annual forbs & grasses > shrubs > succulents > short grasses (slender grama, Rothrock grama).
Sub-dominant:
Other:
Additional: |
|
| 13. |
Amount of plant mortality and decadence (include which functional groups are expected to show
mortality or decadence): Some. Approximately 50% basal cover of midgrass species and 75-80% basal cover of short grass species has been lost due to prolonged drought. |
|
| 14. |
Average percent litter cover (76%) and depth (5
inches): |
|
| 15. |
Expected annual production (this is TOTAL above-ground production, not just forage production:
600 lbs/ac unfavorable precipitation, 1100 lbs/ac normal precipitation, 1800 lbs/ac faborable precipitation |
|
| 16. |
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 indicator, we are
describing what in NOT expected in the reference state for the ecological site: Mesquite, Lehmann lovegrass and prickley pear |
|
| 17. |
Perennial plant reproductive capability: No affected even following several years of prolonged drought period for region. Black grama producing stolons, all other species produce seed. |
|
| |
| Reference Sheet Approval: |
| Approval |
Date |
| S. Cassady |
2/8/2007 |
|
|
|
|
|
Ecological Site Description
Back to Top