Natural Resources
Conservation Service
Ecological site R060BE565MT
Claypan 10-14
Last updated: 8/27/2024
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): 060B–Pierre Shale Plains, Northern Part
MLRA 060B, Pierre Shale Plains (Northern Part), is almost entirely in Montana (94 percent) and Wyoming (6 percent). The area makes up about 2,160,000 acres and occurs in the uplands between most of the major rivers in southeastern Montana and northeastern Wyoming. 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 deeply eroded.
The shale plains have long, smooth, gentle to strong slopes. Slopes along drainageways and streams are moderately steep or steep. Elevation ranges from 1,900 to 3,500 feet on uplands. Marine and continental sediments of the Cretaceous Montana Group underlie most of this MLRA.
The average annual precipitation in the area is 14 inches and ranges from 11 to 17 inches. Most of the annual precipitation occurs as high-intensity, convective thunderstorms during the growing season. Precipitation in winter occurs mainly as snow, which usually is accompanied by high winds that cause much drifting.
The average annual temperature is 43 to 46 degrees Fahrenheit. The freeze-free period averages 142 days and ranges from 130 to 160 days. The frost-free period averages 120 days and ranges from 110 to 135 days.
The dominant soil orders in this MLRA are Alfisols, Entisols, and Vertisols. The soils in the area dominantly have a frigid soil temperature regime, an ustic soil moisture regime, and smectitic mineralogy. The soils are shallow to very deep, generally well drained, and clayey.
The area supports native prairie vegetation characterized by a diversity of cool-season and warm-season grasses, sedges, forbs, and shrubs. A majority of this area is in farms or ranches and comprised of rangeland used for livestock grazing. Some small areas of nearly level to moderately sloping soils are used for winter wheat or for livestock feed crops.
Classification relationships
NRCS Soil Geography Hierarchy
• Land Resource Region: Western Great Plains
• Major Land Resource Area (MLRA): 060B Pierre Shale 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 Missouri Plateau Section (331M)
National Vegetation Classification Standard (Federal Geographic Data Committee, 2008)
• Class: Xeromorphic Woodland, Scrub and Herb Vegetation Class (3)
• Subclass: Cool Semi-Desert Scrub and Grassland Subclass (3.B)
• Formation: Cool Semi-Desert Scrub and Grassland Formation (3.B.1)
• Division: Cool Semi-Desert Scrub and Grassland Division (3.B.1.Ne)
• Macrogroup: Artemisia tridentata - Artemisia tripartita ssp. tripartita - Purshia tridentata Steppe and Shrubland Macrogroup (3.B.1.Ne.3)
• Group: Artemisia tridentata ssp. wyomingensis - Artemisia tridentata ssp. tridentata Steppe & Shrubland Group (3.B.1.Ne.3.a)
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: Sagebrush Steppe (43e)
Ecological site concept
This ecological site occurs on nearly level to gently sloping uplands, terraces, and fans at elevations ranging from 1,900 to 3,500 feet. Slopes range from 0 to 15 percent but are generally less than 8 percent. This site occurs on all aspects, although aspect is not a significant factor. The distinguishing characteristic of this site is the presence of a dense, sodium-affected (natric) horizon between depths of 4 to 8 inches from the soil surface. The natric horizon exhibits columnar structure, is very hard and severely limits both root penetration and infiltration. Soil surface horizons (0 to 4 inches) are very fine sandy loam to silty clay loam, and the natric horizon is loam, clay, or clay loam.
Associated sites
R060BE566MT |
Clayey 10-14 The Clayey ecological site occurs on slopes ranging from 0 to 15 percent, has a soil depth of 20 to 72 inches to shale, and has higher total annual production. The Clayey ecological site is located on similar landform positions as the Claypan ecological site. |
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R060BE568MT |
Dense Clay 10-14 The Dense Clay ecological site occurs on slopes ranging from 0 to 15 percent, has a soil depth of 60 to 72 inches to shale, and has lower total annual production. The Dense Clay ecological site is located on similar landform positions as the Claypan ecological site. |
R060BE579MT |
Loamy 10-14 The Loamy ecological site occurs on slopes ranging from 0 to 15 percent, has a soil depth of 20 to 72 inches, and has higher total annual production. The Loamy ecological site is located on similar landform positions as the Claypan ecological site. |
R060BE572MT |
Saline Upland 10-14 The Saline Upland ecological site occurs on slopes ranging from 35 to 40 percent, has a soil depth of 20 to 40 inches, and has lower total annual production. The Saline Upland ecological site is located on similar landform positions as the Claypan ecological site. |
Similar sites
R060BE568MT |
Dense Clay 10-14 The Dense Clay ecological site occurs on slopes ranging from 0 to 15 percent, has a soil depth of 60 to 72 inches to shale, and has lower total annual production. The Dense Clay ecological site is located on similar landform positions as the Claypan ecological site. |
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R060BE165MT |
Thin Claypan 10-14 The Thin Claypan ecological site occurs on slopes ranging from 0 to 15 percent, has a soil depth of 60 to 72 inches to shale, and has lower total annual production. The Thin Claypan ecological site is located on similar landform positions as the Claypan ecological site. |
R060BE572MT |
Saline Upland 10-14 The Saline Upland ecological site occurs on slopes ranging from 35 to 40 percent, has a soil depth of 20 to 40 inches, and has lower total annual production. The Saline Upland ecological site is located on similar landform positions as the Claypan ecological site. |
Table 1. Dominant plant species
Tree |
Not specified |
---|---|
Shrub |
(1) Artemisia tridentata ssp. wyomingensis |
Herbaceous |
(1) Pascopyrum smithii |
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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) |
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) |
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 | - | Prescribed fire and wildfire, mechanical and chemical treatments, biological processes |
---|---|---|
1.1B | - | Drought, improper grazing management |
1.2A | - | Approximately 30 years post-fire regrowth |
1.2B | - | Drought, improper grazing management, multiple fires in close succession |
1.3B | - | Normal or above average precipitation, proper grazing management |
1.3A | - | Prescribed fire and wildfire, mechanical and chemical treatments, biological processes |
1.4B | - | Normal or above average precipitation; proper grazing management |
1.4A | - | Approximately 30 years post-fire regrowth |
State 2 submodel, plant communities
2.1A | - | Prescribed fire and wildfire, mechanical and chemical treatments, biological processes |
---|---|---|
2.2A | - | Approximately 30 years post-fire regrowth |