Science · Soils
Alfisol
Soils with clay-enriched subsurface horizons and relatively high base status.
USDA Soil Taxonomy order
Profile
- Diagnostic
- Argillic, kandic or natric horizon in the required setting
- Bases
- Higher base saturation criterion than Ultisols
- Texture
- Surface may range widely in texture
- Fertility
- Test nutrient supply rather than assuming fertility
Water & soil targets
- Moisture (VWC)
- Site-calibrated; measure field capacity and dry-down
- Salinity tolerance
- Not inferable from soil classification; test EC, sodicity and water chemistry
- Drought tolerance
- Not inferable from taxonomy; measure accessible storage and plant response
Soil orders and WRB groups are not textures. Determine horizon-specific retention, field capacity, drainage, rooting depth and seasonal hydrology before setting irrigation triggers.
Problems to watch
- Clay-horizon drainage restriction
- Erosion
- Compaction
Stress signs
- Perched wetness
- Exposed subsoil
- Shallow rooting
Where you'll find it
- Soil survey interpretation
- Landscape suitability assessment
More soils
All Science profilesGeneral agronomic guidance and typical ranges; actual targets vary by site, soil, climate and season.