Natural Resources
Conservation Service
Ecological site R035XB018NM
Loamy Bottom 6-10"
Accessed: 12/22/2024
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.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Atriplex canescens |
| Herbaceous |
(1) Pascopyrum smithii |
Physiographic features
This site occurs on floodplains along ephemeral streams. Therefore, it benefits from run-in moisture from adjacent areas. Slopes range from 0 to 1 percent. Elevations range from 5,300 to 5,800 feet.
Table 2. Representative physiographic features
| Landforms |
(1)
Flood plain
|
|---|---|
| Elevation | 1,615 – 1,768 m |
| Slope | 0 – 1% |
| Aspect | Aspect is not a significant factor |
Climatic features
Mean annual precipitation varies from 5 to 8 inches with about 60% of it coming as rain from April through October. May and June are the driest months. Most of the precipitation from November through March comes as snow. High-velocity winds are common in late winter and early spring.
Mean temperatures for the hottest month, July, are about 83 degrees F. The coldest month is January, when the mean temperature is about 27 degrees F. Extreme temperatures of 104 and -17 degrees F have been recorded. The frost-free period ranges from 140 to 160 days.
The cool-season plants start growth in March and end with plant maturity and seed dissemination about mid-June. Warm-season plants grow from June through September, taking advantage of the moisture and warmth from tropical air out of the Gulf of Mexico. About 40 percent of the total precipitation is received during these summer months. The other 60 percent, received from fall through spring, influences cool-season plants.
The tabular climate summary for this ESD was generated by the Climate Summarizer
(http://www.nm.nrcs.usda.gov/technical/handbooks/nrph/Climate_Summarizer.xls) using data
from the following climate stations (results are unweighted averages):
296098 Newcomb, NM (Period of record = 1948 to 1971)
298284 Shiprock, NM (Period of record = 1926 to 2006)
Table 3. Representative climatic features
| Frost-free period (average) | 167 days |
|---|---|
| Freeze-free period (average) | 186 days |
| Precipitation total (average) | 178 mm |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
This site occurs on floodplains along ephemeral streams. Therefore, it benefits from run-in moisture from adjacent areas.
Soil features
The soils are very deep and well drained. They are formed in alluvium derived from sandstone and shale. Surface textures include loam. The subsoil has textures of silty clay loam, fine sandy loam, silt loam, and very fine sandy loam. Permeability is moderately slow. Available water holding capacity is high. Runoff is slow, and the hazard of water erosion is slight. The hazard of soil blowing is severe. The soils are mildly to strongly alkaline (pH 7.4-9.0), nonsaline (EC 0-2), and slightly sodic (SAR 5-13).
Shiprock SSA:
175 – Suwanee loam
Additional information may be found in Section II of the Field Office Technical Guide.
Ecological dynamics
This ecological site has a plant community made up primarily of shortgrasses, midgrasses, shrubs, and a relatively small amount of forbs. In the reference plant community there is a mixture of cool-season and warm-season grasses.
Plant species most likely to invade or increase on this site when it deteriorates are black greasewood, annual sunflower, cocklebur, goldenweed, Russian thistle, and threadleaf rubber rabbitbrush. Continuous livestock grazing during winter and spring decreases the cool-season grasses and increases lower forage value grasses and shrubs.
The reference plant community has been determined by study of relict areas or areas protected from excessive grazing. Trends in plant communities going from heavily grazed areas to lightly grazed areas, seasonal use pastures, and historical accounts have also been used.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Reference Plant Community
Community 1.1
Reference Plant Community
This ecological site has a plant community made up primarily of shortgrasses, midgrasses, shrubs, and a relatively small amount of forbs. In the reference plant community there is a mixture of cool-season and warm-season grasses. Plant species most likely to invade or increase on this site when it deteriorates are black greasewood, annual sunflower, cocklebur, goldenweed, Russian thistle, and threadleaf rubber rabbitbrush. Continuous livestock grazing during winter and spring decreases the cool-season grasses and increases lower forage value grasses and shrubs. The reference plant community has been determined by study of relict areas or areas protected from excessive grazing. Trends in plant communities going from heavily grazed areas to lightly grazed areas, seasonal use pastures, and historical accounts have also been used.
Figure 4. Annual production by plant type (representative values) or group (midpoint values)
Table 4. Annual production by plant type
| Plant type | Low (kg/hectare) |
Representative value (kg/hectare) |
High (kg/hectare) |
|---|---|---|---|
| Grass/Grasslike | 720 | 1116 | 1513 |
| Shrub/Vine | 166 | 285 | 404 |
| Forb | 11 | 56 | 101 |
| Total | 897 | 1457 | 2018 |
Figure 5. Plant community growth curve (percent production by month). NM0374, R035XB018NM-Loamy Bottom 6-10 inch HCPC. Average Precipitation Year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| J | F | M | A | M | J | J | A | S | O | N | D |
| 6 | 6 | 7 | 6 | 6 | 5 | 11 | 14 | 12 | 12 | 8 | 7 |
Additional community tables
Table 5. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (kg/hectare) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Grass/Grasslike
|
||||||
| 1 | western wheatgrass | 224–605 | ||||
| western wheatgrass | PASM | Pascopyrum smithii | 224–605 | – | ||
| 2 | alkali sacaton | 135–404 | ||||
| alkali sacaton | SPAI | Sporobolus airoides | 135–404 | – | ||
| 3 | squirreltail | 9–101 | ||||
| squirreltail | ELEL5 | Elymus elymoides | 9–101 | – | ||
| 4 | galleta | 9–101 | ||||
| James' galleta | PLJA | Pleuraphis jamesii | 9–101 | – | ||
| 5 | other perennial grasses | 45–202 | ||||
|
Forb
|
||||||
| 5 | perennial forbs | 9–61 | ||||
| 7 | annual forbs | 0–40 | ||||
|
Shrub/Vine
|
||||||
| 8 | fourwing saltbush | 135–404 | ||||
| fourwing saltbush | ATCA2 | Atriplex canescens | 135–404 | – | ||
| 9 | threadleaf rabbitbrush | 0–40 | ||||
| rubber rabbitbrush | ERNAC2 | Ericameria nauseosa ssp. consimilis | 0–40 | – | ||
| 10 | other shrubs | 0–101 | ||||
Interpretations
Animal community
Livestock -- This site is suitable for yearlong grazing by all classes of livestock. Accessibility is usually very good because stock tanks can be built in these areas. Erosion is not a hazard unless the vegetative cover has been severely reduced. The site may be hazardous to livestock during periods of occasional flooding following convective summer storms.
Wildlife -- Riparian plants may grow near watercourses where soil moisture is adequate. These types of vegetation provide habitat for a large number of wildlife species. Riparian vegetation should be replanted in drainages where the soil is moist. Protection from grazing is essential. Competition between cattle and wildlife is high year-round.
Hydrological functions
Permeability is moderately slow. Available water holding capacity is high. Runoff is slow, and the hazard of water erosion is slight.
Recreational uses
Hunting, horseback riding, and wildlife observation are occasional recreational activities on this site. Excellent condition loamy bottoms have tremendous aesthetic appeal as grasslands.
Wood products
This site has no significant value for wood products.
Supporting information
Type locality
| Location 1: San Juan County, NM | |
|---|---|
| Township/Range/Section | T24N R17W S11 |
| General legal description | Newcomb SE Quad – along Captain Tom Wash, 7 miles NE of Newcomb, NM – NE ¼ of Sec. 11, T24N, R17W - Navajo Reservation, NM. |
Contributors
John Tunberg
Michael Carpinelli
Unknown
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | |
|---|---|
| Contact for lead author | |
| Date | |
| Approved by | |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction 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:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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:
-
Perennial plant reproductive capability:
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