Natural Resources
Conservation Service
Ecological site R058AY713MT
Saline Overflow 10-14
Last updated: 8/29/2024
Accessed: 11/21/2024
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.
MLRA notes
Major Land Resource Area (MLRA): 058A–Northern Rolling High Plains, Northern Part
MLRA 058A, Northern Rolling High Plains (Northern Part), is an expansive and agriculturally and ecologically significant area encompassing 26 counties in southeast Montana (99 percent) and northeast Wyoming (1 percent). It stretches approximately 290 miles from east to west and 220 miles from north to south and comprises approximately 42,350 square miles (26,875,928 acres). The area is within the Missouri Plateau, Unglaciated, Section of the Great Plains Province of the Interior Plains. It is an area of old plateaus and terraces that have been eroded. Slopes generally are gently rolling to steep, and wide belts of steeply sloping badlands border a few of the larger river valleys. In some areas flat-topped, steep-sided buttes rise sharply above the general level of the plains. Elevations generally range from 1,950 to 3,280 feet, increasing from east to west and from north to south.
Tertiary continental shale, siltstone, and sandstone of the Fort Union Formation underlie the eastern one-third to one-half of this area. Marine and continental sediments of the Cretaceous Montana Group underlie the rest of the MLRA, generally at the higher elevations. There are also younger Cretaceous sediments of the Livingston Group occurring between the higher elevation Montana Group sediments and the lower elevation Tertiary sediments. The dominant soil orders in MLRA 058A are Entisols and Inceptisols. The soils in the area dominantly have a frigid soil temperature regime, an ustic soil moisture regime, and mixed or smectitic mineralogy. They range from shallow to very deep and are generally well drained and clayey or loamy.
The area primarily supports native prairie vegetation characterized by a variety of cool-season and warm-season graminoids, forbs, and shrubs. In the western portion of the area, cool-season grasses such as western wheatgrass and bluebunch wheatgrass are dominant but, in the eastern portion of the area, warm-season grasses such as little bluestem and sideoats grama become dominant. Wyoming big sagebrush, silver sagebrush, and fringed sagewort are common shrub species throughout the area. Forested areas occur in rough hilly areas and river breaks, particularly in areas with higher precipitation. Common tree species are ponderosa pine and Rocky Mountain juniper with scattered pockets of Douglas fir.
More than 75 percent of this MLRA is native rangeland utilized for livestock production and more than 50 percent of the MLRA consists of privately-owned ranches. Approximately 15 percent of the MLRA is used as cropland. Other land uses including forestland, urban development, water, and other uses combine for less than 10 percent of the total land use.
Classification relationships
NRCS Soil Geography Hierarchy
• Land Resource Region: Western Great Plains
• Major Land Resource Area (MLRA): 058A Northern Rolling High Plains, Northern Part
National Hierarchical Framework of Ecological Units (Cleland et al., 1997; McNab et al., 2007)
• Domain: Dry
• Division: Temperate Steppe
• Province: Great Plains-Palouse Dry Steppe Province (331)
• Section: North Central Highlands (331K) and Powder River Basin (331G)
National Vegetation Classification Standard (Federal Geographic Data Committee, 2008)
• Class: Mesomorphic Shrub and Herb Vegetation Class (2)
• Subclass: Shrub and Herb Wetland Subclass (2.C)
• Formation: Salt Marsh Formation (2.C.5)
• Division: Distichlis spicata - Hordeum jubatum Great Plains Saline Marsh Division (2.C.5.Na)
• Macrogroup: Great Plains Saline Wet Meadow and Marsh Macrogroup (2.C.5.Na.1)
• Group: Western Great Plains Saline Wet Meadow Group (2.C.5.Na.1.b)
EPA Ecoregions
• Level 1: Great Plains (9)
• Level 2: West-Central Semi-Arid Prairies (9.3)
• Level 3: Northwestern Great Plains (9.3.3)
• Level 4: Montana Central Grasslands (43n), River Breaks (43c), and Pine Scoria Hills (43p)
Ecological site concept
This ecological site occurs on overflow areas where salt or alkali accumulations are apparent and salt tolerant plants dominate the vegetative component. This site occurs on level to nearly level depressions, drainageways, or stream terraces at elevations ranging from 1,900 to 3,500 feet. Slopes are generally less than 4 percent. This site occurs on all aspects, although aspect is not a significant factor. The soils of this ecological site are moderately to strongly saline or sodic and salt or sodium accumulations are apparent on or near the soil surface. Soils are typically deep to very deep and well drained to somewhat poorly drained. The soil textures are typically loam, clay loam, or silty clay loam.
Associated sites
R058AY737MT |
Saline Subirrigated 10-19 This site occurs on similar landforms adjacent to the Saline Overflow ecological site. It typically occurs on lower terraces where groundwater is closer to the surface. |
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R058AY711MT |
Overflow 10-14 This site occurs on similar landscapes and terrace positions to the Saline Overflow ecological site, but in areas that have not accumulated salts in the soil profile. |
Similar sites
R058AY737MT |
Saline Subirrigated 10-19 This site differs from the Saline Overflow ecological site in that it receives additional moisture primarily from groundwater rather than from surface water. Depth to a water table is 24 to 40 inches. |
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R058AY711MT |
Overflow 10-14 This site differs from the Saline Overflow ecological site in that soils do not contain accumulated salts within the 4 inches of the soil surface. This site supports a diverse herbaceous plant community and is more productive. |
R058AY714MT |
Saline Upland 10-14 This site differs from the Saline Overflow ecological site in that it occurs in uplands or ephemeral drainageways and does not receive enough additional moisture to significantly increase production. Clay content is 35 percent or less. |
R058AY705MT |
Dense Clay Non-Sodic 10-14 This site differs from the Saline Overflow ecological site in that it occurs in uplands or ephemeral drainageways and does not receive enough additional moisture to significantly increase production. Clay content is greater than 35 percent. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Sarcobatus vermiculatus |
Herbaceous |
(1) Pascopyrum smithii |
Click on box and path labels to scroll to the respective text.
Ecosystem states
T1A | - | Prolonged drought, improper grazing, or a combination of these factors |
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T1B | - | Introduction of non-native invasive species (annual bromes, crested wheatgrass, noxious weeds, etc.) |
T1C | - | Tillage or herbicide application and seeding of annual crops or non-native hayland (frequently combined with irrigation practices) |
R2A | - | Proper grazing management in combination with rangeland seeding, grazing land mechanical treatment, and timely moisture (management intensive and costly). |
T2A | - | Introduction of non-native invasive species (annual bromes, crested wheatgrass, noxious weeds, etc.) |
T2B | - | Tillage or herbicide application and seeding of annual crops or non-native hayland (frequently combined with irrigation practices) |
T3A | - | Tillage or herbicide application and seeding of annual crops or non-native hayland (frequently combined with irrigation practices) |
T4A | - | Cessation of annual cropping |
T5A | - | Tillage or herbicide application and seeding of annual crops or non-native hayland (frequently combined with irrigation practices) |
State 1 submodel, plant communities
1.1A | - | Drought, improper grazing management |
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1.2A | - | Normal or above average precipitation, proper grazing management |