Soil series profile

Pastura soil series

Pastura is a well drained soil with a loam surface, mapped on 863,827 acres in 12 counties across 4 states. Hydrologic group D.

#232 by mapped area loamy Ustollic Paleorthids (Aridisols)

Drainage class: Well drained
Hydrologic group: D
Typical topsoil pH: 8.2
Mapped area: 864k

Typical Pastura profile

Texture and pH by depth

Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).

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Typical Pastura horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–2 in (H1)	Loam	8.2	25%	39%	1.5%
2–13 in (H2)	Loam	8.2	27%	35%	0.75%
13–49 in (H3)	Cemented material	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive Pastura map unit (Pastura loam, gently sloping, survey area NM632). Other map units of this series vary within the series range.

Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Pastura soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Pastura soils is moderately alkaline: pH 8.2. Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).

Loamy topsoil (loam, silt loam and similar) covers 96% of mapped Pastura acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (63% of mapped Pastura acres).

>99% of mapped Pastura acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

On 98% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.

For a septic system

For conventional septic absorption fields, NRCS rates 98% of the acres in mapped Pastura soils very limited, 2% somewhat limited and 0% not limited.

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Pastura soil is found

Mapped acres

Pastura is mapped in New Mexico, Arizona, Texas and Utah.

Counties with the most mapped Pastura soil
County	Acres	Share of county land
Lincoln County, NM	310,756	11.5%
Guadalupe County, NM	249,027	12.9%
Yavapai County, AZ	124,261	3.0%
Torrance County, NM	43,903	2.1%
Chaves County, NM	36,732	0.9%
De Baca County, NM	34,561	2.3%
Washington County, UT	18,369	1.7%
Harding County, NM	15,115	1.1%
Sherman County, TX	13,081	2.2%
Coconino County, AZ	9,038	0.1%
Moore County, TX	7,640	1.3%
Sandoval County, NM	1,344	0.1%

Septic absorption fields

NRCS rating, share of Pastura acres

Not limited 0%

Somewhat limited 2%

Very limited 98%

Not rated <1%

Septic tank absorption field rating across mapped Pastura acres. Scale 0 to 100% of mapped land.

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Septic tank absorption field rating across mapped Pastura acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	1.6%
Very limited	98.2%
Not rated	0.2%

Drainage, water table and flooding

Share of Pastura acres

Depth to seasonal high water table: None reported within about 6.5 feet (median where reported).
Flooding: Not mapped as flooding on most acres.
Slope: Typically 3–6% (median 4%).
Topsoil organic matter: Median 1.5%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained >99%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated <1%

Drainage class across mapped Pastura acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Pastura acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	99.8%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	0.2%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%

B: moderate infiltration 2%

C: slow infiltration 0%

D: very slow infiltration (clayey, shallow or wet) 98%

A/D: D as is, A if drained 0%

B/D: D as is, B if drained 0%

C/D: D as is, C if drained 0%

Not rated <1%

Hydrologic soil group across mapped Pastura acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped Pastura acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	1.6%
C: slow infiltration	0.0%
D: very slow infiltration (clayey, shallow or wet)	98.2%
A/D: D as is, A if drained	0.0%
B/D: D as is, B if drained	0.0%
C/D: D as is, C if drained	0.0%
Not rated	0.2%

Sources & data dates

Source: USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date: SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope: All map unit components named Pastura (component kind "Series") in SSURGO: 863,827 acres.
Method: Shares are by mapped acres of Pastura components. The profile comes from the single largest Pastura component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Pastura.