Entisols: Young Soils with No Diagnostic Horizons

What makes a soil an Entisol

The rule is an absence: Entisols have no diagnostic horizons. Many have an ochric epipedon and a few an anthropic one, many are sandy or very shallow, and some sit on steep slopes that are actively eroding.^[2]

The Soil Science Society of America describes little to no development beyond an identifiable topsoil. These soils form on recently deposited sediment, often where deposition outpaces soil development: active flood plains, dunes, landslide areas and ground left by retreating glaciers. The name comes from “recent”, and worldwide they are the second largest group after Inceptisols, about 16% of the land.^[1]

Mostly an A horizon over C material

In the survey, the most common Entisol sequence is A–C, a topsoil straight over C material, on 54.1% of described acres. A B horizon turns up on only 20.9%, while C material is in 90.2% of the profiles.^[3]

The next sequences are A–B–C (18.8 million acres), O–A–C (10.5 million acres) and C (10.2 million acres). The A horizon has a median thickness of 5.1 inches (13 cm), thinner than the 6.3 inches (16 cm) of all US soils, and bedrock appears in 12.5% of profiles, at a median 11.8 inches (30 cm) where it does.^[3]

Where a parent material is recorded, it’s most often alluvium (40.2%), residuum (17.0%) and eolian (wind-blown) sand (15.7%). The first mineral layer is most often sandy loam (21.0%), sand (20.0%), silt loam (15.6%), loam (14.3%) and loamy sand (13.0%); sand and loamy sand alone make up 33.0%.^[3]

Typical properties of the first mineral layer

Median, with the middle half of the acres in brackets.

The median pH of the first mineral layer, 7.4, is slightly alkaline.^[3][4]

Entisol suborders and how they’re used

NRCS describes these Entisol suborders:

• Aquents are the wet Entisols, and they’re widely distributed. They support vegetation that tolerates permanent or periodic wetness and are used mostly as pasture, cropland, forest or wildlife habitat.
• Arents have no diagnostic horizons because they’ve been deeply mixed by plowing. They’re important soils for irrigated crop production in California.
• Orthents are mainly in the Western States, commonly on recent erosional surfaces, and are used mostly as rangeland, pasture or wildlife habitat.
• Psamments are sandy in all layers. In some arid and semiarid climates they’re among the most productive rangeland soils, but some that are nearly bare are subject to soil blowing and drifting and give wheeled vehicles poor support. Some of the largest areas are in Nebraska, California, Minnesota, Wisconsin, Michigan, Arizona and Florida.^[2]

Fluvents, the Entisols of recent water-laid sediment on flood plains, have their own section on our alluvial soil page.^[2] The survey data doesn’t record suborders, so none of them gets an acreage here.

Wet and droughty Entisols

Entisols run to both ends of the drainage scale. 33.2% of their acres are excessively or somewhat excessively drained, and 10.3% are poorly or very poorly drained.^[3][5] The wet end has its own suborder in NRCS’s scheme, the Aquents.^[2]

35.4% of Entisol acres are in hydrologic soil group A, the group where water soaks in fastest, the largest share of any order.^[3][6]

Are Entisols good for farming?

Another 6.0% would be prime if drained, irrigated or protected from flooding, and 6.9% is farmland of statewide or local importance. Most of the rest sits in land-capability Classes VI–VIII (72.7% of rated acres); 22.0% is in the cultivable Classes I–IV.^[3][7][8]

NRCS lists the uses suborder by suborder: Orthents are used mostly as rangeland, pasture or wildlife habitat; some Psamments are among the most productive rangeland soils in arid and semiarid climates; Aquents serve as pasture, cropland, forest or wildlife habitat; and Arents are important for irrigated crops in California.^[2]

Check one address with the prime farmland checker.

Entisols vs Inceptisols

The two orders differ by how far development has gone. Entisols show little to none beyond a topsoil; Inceptisols show a moderate degree of development but haven’t built up much clay in the subsoil.^[1] The University of Nebraska–Lincoln’s PASSEL lessons sum them up as “little, if any horizon development” against “beginning of horizon development”.^[9]

In the survey that gap shows up as the B horizon: 88.6% of described Inceptisol acres have one, against 20.9% of Entisol acres.^[3]

Where Entisols are in the US

California has the most Entisol acres, 25.0 million, and they’re the leading order in California and Wyoming. As a share of each state’s own soil acres they peak in Nebraska:^[3]

Most widespread Entisol series

Valentine (Nebraska) covers 10.8 million acres, more than any other series of any order in our data; Valent (Colorado) and Cabbart (Montana) come next. Each name links to its official USDA description.^[3][10]

Download the Entisols data (CSV)

Entisols compared with other orders

Among the twelve orders, Entisols rank fourth by US acres, and only five orders (Andisols, Aridisols, Gelisols, Histosols and Spodosols) have a smaller prime-farmland share.^[3][7]

Histosols show a dash: their surface is organic material (peat or muck), so a topsoil (A) or surface pH median would describe mineral soil beneath it.

Frequently asked questions

What are Entisols?

Soils with no diagnostic horizons. Many are sandy or very shallow, and some are on steep, actively eroding slopes.^[2]

Why are Entisols called young soils?

They form on recently deposited sediment, often where deposition is faster than soil development, so they show little development beyond a topsoil. The name comes from “recent”.^[1]

What are the types of Entisols?

NRCS describes Aquents (wet), Arents (deeply mixed), Orthents (on recent erosional surfaces, mainly in the West), Psamments (sandy in all layers) and Fluvents (on flood-plain sediment).^[2]

Are Entisols good for farming?

Few are prime farmland: 3.0% of their acres, against 12.5% nationally. NRCS lists rangeland, pasture and wildlife habitat among the main uses of its suborders, and irrigated crops for California’s Arents.^[3][7][2]

Where are Entisols found in the US?

California, Nebraska and Alaska have the most acres, and they make up 45.2% of Nebraska’s soil acres with an order.^[3]

What is the difference between Entisols and Inceptisols?

Development. Entisols show little to none beyond a topsoil; Inceptisols show a moderate degree but little clay buildup in the subsoil. 88.6% of described Inceptisol acres have a B horizon, against 20.9% of Entisol acres.^[1][3]

What does ‘Entisol’ mean?

It comes from “recent”: these are soils of newly laid sediment.^[1]