Union County, Arkansas

Survey Area AR139• Arkansas

The dominant drainage class is Moderately well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Ultisols — strongly weathered soils with clay-enriched subsoils, common in warm humid climates. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Union County, Arkansas. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map Unit	Acres	Drainage	Hydro Group	Dwellings	Septic
Sacul-Sawyer complex, 1 to 8 percent slopes	177K	Moderately well drained	D	Somewhat limited	Very limited
Guyton silt loam, 0 to 1 percent slopes, frequently flooded	104K	Poorly drained	C/D	Very limited	Very limited
Warnock-Smithdale complex, 1 to 7 percent slopes	44K	Moderately well drained	C	Somewhat limited	Very limited
Harleston fine sandy loam, 1 to 8 percent slopes	29K	Moderately well drained	C	Very limited	Very limited
Sacul-Sawyer complex, 8 to 15 percent slopes	27K	Moderately well drained	D	Somewhat limited	Very limited
Sacul fine sandy loam, 1 to 8 percent slopes	25K	Moderately well drained	D	Somewhat limited	Very limited
Una silty clay loam, 0 to 1 percent slopes, frequently flooded	24K	Poorly drained	D	Very limited	Very limited
Sawyer very fine sandy loam, 1 to 8 percent slopes	23K	Moderately well drained	C	Very limited	Very limited
Bibb fine sandy loam, 0 to 1 percent slopes, frequently flooded	22K	Poorly drained	B/D	Very limited	Very limited
Amy silt loam, 0 to 1 percent slopes, rarely flooded	21K	Poorly drained	C/D	Very limited	Very limited
Smithton fine sandy loam, 0 to 2 percent slopes	21K	Poorly drained	C/D	Very limited	Very limited
Sacul fine sandy loam, 15 to 35 percent slopes	20K	Moderately well drained	D	Very limited	Very limited
Rosalie-Warnock complex, 1 to 8 percent slopes	20K	Moderately well drained	B	Not limited	Somewhat limited
Warnock fine sandy loam, 1 to 7 percent slopes	18K	Moderately well drained	C	Somewhat limited	Very limited
Una silty clay loam, 0 to 1 percent slopes, ponded	15K	Poorly drained	D	Very limited	Very limited
Smithdale fine sandy loam, 3 to 8 percent slopes	15K	Well drained	B	Not limited	Very limited
Sacul fine sandy loam, 8 to 15 percent slopes	12K	Moderately well drained	D	Somewhat limited	Very limited
Darden loamy fine sand, 1 to 8 percent slopes	11K	Excessively drained	A	Not limited	Very limited
Smithdale fine sandy loam, 8 to 15 percent slopes	7K	Well drained	B	Somewhat limited	Very limited
Water	6K		D	Not rated	Not rated

Soil Orders in This Area

The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.

Ultisols

Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

What This Means

Building & Foundations

About 43% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

Septic Systems

About 95% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.