Natural Resources
Conservation Service
Major Land Resource Area 042B
Major Land Resource Area
Accessed: 04/19/2026
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Next, learn more about the selected ecological site group and its characteristic dynamics by browsing the ecological site group description and exploring alternative state and transition model formats.
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Ecological site groups
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This key only applies to MLRA 70C. As of now, there are no LRUs for 70C. In the future, keys should be developed for individual LRUs.
This key only applies to MLRA 70D. As of now, no LRUs have been established for this MLRA.
Flooded (low-lying landscape position, evidence of water flow and/or high production, narrow inset fans, bottomlands, river flood plains or meadows; Flooded soils group)
Not flooded (hills, convex portions of piedmont slopes, broad basin floors)
In a river floodplain
ESG10 – Riparian
ESG10 – Riparian
Not in a river floodplain
Level lake plains occupying lowest part of closed depressions in which flood waters persist long enough to prevent perennial vegetation in most areas
ESG9 – Playas and lakebeds
ESG9 – Playas and lakebeds
Swales and depressions within upland landforms or at the margins of playas featuring highly productive vegetation
ESG8 – Bottomlands
ESG8 – Bottomlands
Exposed bedrock absent and few if any cobbles and stones
Exposed bedrock present or surface cobbles and stones common
Soil surface texture loamy sand to medium sandy loam, subsoil non gravelly, gypsum absent
Soil surface textures are fine sandy loam to clay loam, subsoil non gravelly, gypsum may or may not be present
Soil surface gravelly, soil profile gravelly to skeletal
ESG5 – Gravelly
ESG5 – Gravelly
Soil is shallow (< 50 cm) or has a calcic, cambic, or argillic horizon within 1 m, dunes may occur but are separated by areas of finer soil texture
ESG1 – Sandy
ESG1 – Sandy
Soil is not shallow (≥ 50 cm) and does not have a clear pedogenic horizon, continuous undulating surface or dunes
ESG2 – Deep sand
ESG2 – Deep sand
Subsoil moderately to strongly saline, often with visible salt accumulation or crusts
ESG4 – Saline
ESG4 – Saline
Subsoil not moderately to strongly saline
Subsoil has a gypsic horizon and/or gypsiferous materials evident at the soil surface
ESG7 – Gypsic
ESG7 – Gypsic
Subsoil lacks a gypsic horizon and gypsum not evident at the surface
ESG3 – Loamy to clayey
ESG3 – Loamy to clayey
Rock at lithic contact is basalt, may be a carbonate layer on top of it
ESG11 – Malpais
ESG11 – Malpais
Rock at lithic contact is not basalt
ESG6 – Bedrock and colluvium
ESG6 – Bedrock and colluvium
Site occurs on a water-collecting landform such as a swale, drainageway bottom, floodplain, or playa.
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–
Site does not meet the criteria for 1a.
Soils contain visible masses of gypsum in the upper 100 cm.
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–
Soils lack visible masses of gypsum in the upper 100 cm.
Root-restrictive layer occurs within 50 cm of the soil surface.
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–
Soils are >50 cm to root-restrictive layer.
Soil texture is fine sandy loam or coarser at the surface, and sand percentage is ≥50 in all horizons in the upper 100 cm.
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–
Soils do not meet the criteria in 4a.
Soils meet both of the following criteria: 1) soil at the surface reacts strongly or violently to 1N HCl. 2) ≥5% calcareous or carbonate-coated fragments at the surface.
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–
All other sites.
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–
Site occurs on a water-collecting landform such as a floodplain, swale or drainageway bottom.
–
–
Site does not meet the criteria for 1a.
Root-restrictive layer occurs within 50 cm of the soil surface.
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–
Soils are >50 cm to root-restrictive layer.
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Additional water
Uplands
Subsurface EC >4 - 040XESG10 Saline Bottoms
Subsurface EC <4
Sand >50% & clay <25% for surface and subsurface - 040XESG13 Sandy Bottoms
Sand <50% or clay >25% for surface and subsurface - 040XESG01 Bottoms
Surface SAR >8
Surface SAR <8
Elevation - 2500-3700 ft - 041XESG62 Thornscrub Saline Hills
Elevation - 3700-4500 ft
042BESG63 – Semi-Desert Grassland Saline Hills
042BESG63 – Semi-Desert Grassland Saline Hills
Elevation - 4500-6000 ft
042BESG38 – Madrean Woodland Saline Hills
042BESG38 – Madrean Woodland Saline Hills
Gypsum >5% surface or >10% subsurface
Gypsum <5% surface and <10% subsurface
Elevation - 3700-4500 ft
042BESG55 – Gypsum Semi-Desert Grassland
042BESG55 – Gypsum Semi-Desert Grassland
Elevation - 4500-6000 ft - 042AESG69 Gypsum Madrean Woodland
Subsurface EC >8 or surface EC >4
Subsurface EC <8 and surface EC <4
Elevation - 2500-3700 ft - 041XESG62 Thornscrub Saline Hills
Elevation - 3700-4500 ft
042BESG63 – Semi-Desert Grassland Saline Hills
042BESG63 – Semi-Desert Grassland Saline Hills
Elevation - 4500-6000 ft
042BESG38 – Madrean Woodland Saline Hills
042BESG38 – Madrean Woodland Saline Hills
EC >1.5 surface or >2 subsurface
EC <1.5 surface and <2 subsurface
Elevation - 2500-3700 ft - 041XESG39 Thornscrub Saline Uplands
Elevation - 3700-4500 ft - 041XESG65 Semi-Desert Grassland Saline Uplands
Elevation - 4500-6000 ft
042BESG66 – Madrean Woodland Saline Uplands
042BESG66 – Madrean Woodland Saline Uplands
Elevation - >6000 ft - 070BESG67 Temperate Forest Saline Uplands
Slope >35% & >40% surface rock
Slope <35% or <40% surface rock
Elevation - 4500-6000 ft - 038XESG19 Madrean Woodland Breaks
Elevation - >6000 ft - 042CESG20 Temperate Forest Breaks
Depth <30cm
Depth: 30-55cm
Depth >55cm
Elevation 2500-3700 ft - 040XESG46 Very Shallow Thornscrub
Elevation - 3700-4500 ft - 042AESG47 Very Shallow Semi-Desert Grassland
Elevation - 4500-6000 ft - 042AESG48 Very Shallow Madrean Woodland
Elevation - 2500-3700 ft - 040XESG42 Shallow Thornscrub
Elevation - 3700-4500 ft - 042AESG43 Shallow Semi-Desert Grassland
Elevation - 4500-6000 ft - 038XESG44 Shallow Madrean Woodland
Rock >30% surface or >30% subsurface
Rock <30% surface and <30% subsurface
Elevation - 3700-4500 ft - 042AESG26 Deep Rocky Semi-Desert Grassland
Elevation - 4500-6000 ft
042BESG27 – Deep Rocky Madrean Woodland
042BESG27 – Deep Rocky Madrean Woodland
Clay >30% surface or >35% subsurface - 041XESG22 Semi-Desert Grassland Clay Uplands
Clay <30% surface and <35% subsurface
Sand >75% or texture is loamy sand or sandier in surface & subsurface
Sand <75% or texture is sandy loam or finer in surface & subsurface
Elevation - 3700-4500 ft
042BESG41 – Semi-Desert Grassland Sandy Uplands
042BESG41 – Semi-Desert Grassland Sandy Uplands
Elevation - 4500-6000 ft
042BESG68 – Madrean Woodland Sandy Uplands
042BESG68 – Madrean Woodland Sandy Uplands
Clay <20% or texture is sandy loam or sandier in surface
Clay >20% or texture is finer than sandy loam in surface
Elevation - 3700-4500 ft - 041XESG35 Semi-Desert Grassland Loamy Uplands
Elevation - 4500-6000 ft
042BESG36 – Madrean Woodland Loamy Uplands
042BESG36 – Madrean Woodland Loamy Uplands
Elevation - 3700-4500 ft - 041XESG30 Semi-Desert Grassland Finer Uplands
Elevation - 4500-6000 ft - 070BESG31 Madrean Woodland Finer Uplands
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Ecological site group keys
MLRA 42.2 Ecological Site Group Key
I.
Flooded (low-lying landscape position, evidence of water flow and/or high production, narrow inset fans, bottomlands, river flood plains or meadows; Flooded soils group)
B.
Not in a river floodplain
1
Level lake plains occupying lowest part of closed depressions in which flood waters persist long enough to prevent perennial vegetation in most areas
... ESG9 – Playas and lakebeds
2
Swales and depressions within upland landforms or at the margins of playas featuring highly productive vegetation
... ESG8 – Bottomlands
II.
Not flooded (hills, convex portions of piedmont slopes, broad basin floors)
A.
Exposed bedrock absent and few if any cobbles and stones
1
Soil surface texture loamy sand to medium sandy loam, subsoil non gravelly, gypsum absent
i.
Soil is shallow (< 50 cm) or has a calcic, cambic, or argillic horizon within 1 m, dunes may occur but are separated by areas of finer soil texture
... ESG1 – Sandy
ii.
Soil is not shallow (≥ 50 cm) and does not have a clear pedogenic horizon, continuous undulating surface or dunes
... ESG2 – Deep sand
2
Soil surface textures are fine sandy loam to clay loam, subsoil non gravelly, gypsum may or may not be present
i.
Subsoil moderately to strongly saline, often with visible salt accumulation or crusts
... ESG4 – Saline
ii.
Subsoil not moderately to strongly saline
a.
Subsoil has a gypsic horizon and/or gypsiferous materials evident at the soil surface
... ESG7 – Gypsic
B.
Exposed bedrock present or surface cobbles and stones common
Key to Ecological Site Groups for MLRA 70C
1a
Site occurs on a water-collecting landform such as a swale, drainageway bottom, floodplain, or playa.
...
1b
Site does not meet the criteria for 1a.
2b.
Soils lack visible masses of gypsum in the upper 100 cm.
3b
Soils are >50 cm to root-restrictive layer.
4a
Soil texture is fine sandy loam or coarser at the surface, and sand percentage is ≥50 in all horizons in the upper 100 cm.
...
4b
Soils do not meet the criteria in 4a.
5a
Soils meet both of the following criteria: 1) soil at the surface reacts strongly or violently to 1N HCl. 2) ≥5% calcareous or carbonate-coated fragments at the surface.
...
Ecological Site Group Ke for MLRA 70D
National Park Service
I.
Additional water
A.
Subsurface EC >4 - 040XESG10 Saline Bottoms
B.
Subsurface EC <4
1
Sand >50% & clay <25% for surface and subsurface - 040XESG13 Sandy Bottoms
2
Sand <50% or clay >25% for surface and subsurface - 040XESG01 Bottoms
II.
Uplands
A.
Surface SAR >8
1
Elevation - 2500-3700 ft - 041XESG62 Thornscrub Saline Hills
B.
Surface SAR <8
1
Gypsum >5% surface or >10% subsurface
ii.
Elevation - 4500-6000 ft - 042AESG69 Gypsum Madrean Woodland
2
Gypsum <5% surface and <10% subsurface
i.
Subsurface EC >8 or surface EC >4
a.
Elevation - 2500-3700 ft - 041XESG62 Thornscrub Saline Hills
ii.
Subsurface EC <8 and surface EC <4
a.
EC >1.5 surface or >2 subsurface
1)
Elevation - 2500-3700 ft - 041XESG39 Thornscrub Saline Uplands
2)
Elevation - 3700-4500 ft - 041XESG65 Semi-Desert Grassland Saline Uplands
4)
Elevation - >6000 ft - 070BESG67 Temperate Forest Saline Uplands
b.
EC <1.5 surface and <2 subsurface
1)
Slope >35% & >40% surface rock
a)
Elevation - 4500-6000 ft - 038XESG19 Madrean Woodland Breaks
b)
Elevation - >6000 ft - 042CESG20 Temperate Forest Breaks
2)
Slope <35% or <40% surface rock
a)
Depth <30cm
(1)
Elevation 2500-3700 ft - 040XESG46 Very Shallow Thornscrub
(2)
Elevation - 3700-4500 ft - 042AESG47 Very Shallow Semi-Desert Grassland
(3)
Elevation - 4500-6000 ft - 042AESG48 Very Shallow Madrean Woodland
b)
Depth: 30-55cm
(1)
Elevation - 2500-3700 ft - 040XESG42 Shallow Thornscrub
(2)
Elevation - 3700-4500 ft - 042AESG43 Shallow Semi-Desert Grassland
(3)
Elevation - 4500-6000 ft - 038XESG44 Shallow Madrean Woodland
c)
Depth >55cm
(1)
Rock >30% surface or >30% subsurface
(a)
Elevation - 3700-4500 ft - 042AESG26 Deep Rocky Semi-Desert Grassland
(2)
Rock <30% surface and <30% subsurface
(a)
Clay >30% surface or >35% subsurface - 041XESG22 Semi-Desert Grassland Clay Uplands
(b)
Clay <30% surface and <35% subsurface
(1)
Sand >75% or texture is loamy sand or sandier in surface & subsurface
(2)
Sand <75% or texture is sandy loam or finer in surface & subsurface
(a)
Clay <20% or texture is sandy loam or sandier in surface
(1)
Elevation - 3700-4500 ft - 041XESG35 Semi-Desert Grassland Loamy Uplands
(b)
Clay >20% or texture is finer than sandy loam in surface
(1)
Elevation - 3700-4500 ft - 041XESG30 Semi-Desert Grassland Finer Uplands
(2)
Elevation - 4500-6000 ft - 070BESG31 Madrean Woodland Finer Uplands
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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