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Carroll County Soil Data

Carroll County, Iowa

USDA SSURGO / PHZM

Avg pH

6.5

Texture

Loam

Drainage

N/A

Organic Matter

3.7%

Hydrologic Group

N/A

Data Story

About Soil in Carroll County, Iowa

Carroll's Balanced Soil Profile

Carroll County features a near-perfect pH of 6.46, aligning closely with both the national median of 6.5 and the state average of 6.43. Its soil score of 78.2 is significantly higher than the Iowa average of 72.9, indicating top-tier land quality. This balance makes it one of the more versatile counties for various agricultural uses.

Silt-Dominant Texture

The soil composition is 44.7% silt, 29.2% sand, and 25.0% clay. This high silt and clay combination gives the soil a silky feel and excellent nutrient-holding capabilities. The moderate sand content ensures that the ground doesn't become too compacted, maintaining vital air pockets for root health.

Solid Organic and Water Capacity

At 3.73%, the organic matter is slightly below the state average of 3.81% but still nearly double the national average of 2.0%. The available water capacity is a strong 0.196 in/in, which sits just above the state benchmark. This ensures reliable moisture access for plants during the critical summer growing months.

Steady Hydrologic Performance

While specific drainage classes are unavailable, the 25% clay content suggests a soil that manages water with moderate speed. It is unlikely to be excessively well-drained or prone to extreme ponding, offering a stable environment for most plants. This middle-ground hydrology is excellent for both farming and residential gardening.

Ready for Harvest in Zone 5a

In Zone 5a, Carroll’s soil is ideally suited for brassicas like broccoli and cabbage that enjoy consistent moisture. The balanced pH means you rarely need to add lime or sulfur to adjust the chemistry. It is a reliable and high-performing county for anyone looking to get their hands in the dirt.

Soil Composition

Loam
Sand: 29.2%
Silt: 44.7%
Clay: 25.0%
Loam

Soil pH

6.5pH
6.45791361964026
Strongly AcidicSlightly AcidicNeutralSlightly AlkalineStrongly Alkaline
Ideal lawn range: 6.0 - 7.0

Soil Series

Detailed soil series data not yet available for this county.

Hydrologic Group

Hydrologic group data not available.

Drainage Class

Drainage class data not available.

Soil Profile

Dominant texture: Loam

O HorizonOrganic layer
0-2"
A HorizonTopsoil
2-10"
B HorizonSubsoil
10-30"
C HorizonParent material
30-60"
R HorizonBedrock
60"+

Typical soil profile. Actual depths vary by location.

Soil Amendment Products

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Frequently Asked Questions

What type of soil does Carroll County have?

Carroll County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 29% sand, 45% silt, and 25% clay. Loamy soils hold moisture well and support a wide range of plants.

Is Carroll County's soil acidic or alkaline?

Carroll County's soil has a pH of 6.5, which is moderately acidic. This range suits many crops and is common across much of the eastern US.

What is the drainage class for Carroll County?

Drainage class data is not currently available for Carroll County.

What crops or plants grow well in Carroll County's soil?

Based on Carroll County's Loam texture, pH of 6.5, and drainage class, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens.

What USDA soil order is found in Carroll County?

The dominant USDA soil order for Carroll County is not currently available in our dataset.

Soil & Planting Advisory: Carroll County

Soil Verdict

Carroll County is in USDA hardiness zone 5a, a cold climate zone. where winter lows can reach -20°F. Freeze-thaw cycles are moderate; soil biology slows in winter but recovers reliably in spring, supporting a broad range of plants.

Planting Guidance

A wide plant palette is possible: deciduous trees, most shrubs, cool-season vegetables, and many perennials thrive here. With extreme winter lows, any marginally hardy plants need heavy mulch and wind protection. Always match plant selections to the specific microclimate of your property — low spots, slopes, and wind exposure can shift effective hardiness by half a zone.

Soil Implications

Moderate freeze-thaw cycles naturally aerate the soil but can also cause compaction in clay-heavy areas; annual core aeration is beneficial. Organic matter amendments decompose at a moderate pace — aim for 3-5% organic content for optimal fertility. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.

Regional Context

Carroll County closely matches the Iowa average hardiness conditions.

Other Counties in Iowa

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Soil data sourced from USDA SSURGO via Soil Data Access. Data is informational only and should not be used as a substitute for on-site soil testing. Contact your local NRCS office for site-specific soil information.