loam

Loam is a soil texture class that combines roughly equal parts of sand, silt, and clay. In practice, loams are made up of about 40% sand, 40% silt, and 20% clay, though the exact mix varies. This balance gives loam its characteristic crumbly feel, workability, and versatility for plant growth.

Physically, loam has moderate porosity, allowing adequate drainage while retaining sufficient moisture for roots. The soil forms stable aggregates that promote good aeration and root penetration. Infiltration is generally steady, reducing crust formation after rain. Loam is typically less prone to compaction than heavy clays and less prone to waterlogging than coarse sands, making it suitable for a wide range of agricultural and garden uses.

Chemically, loams often have better nutrient-holding capacity than sandy soils because of the presence of clay and organic matter; cation exchange capacity is moderate, supporting a diverse plant range. Fertility is commonly good, and pH tends toward neutral, though it varies with parent material and management. Organic matter enhances structure, moisture retention, and microbial activity.

Subtypes include sandy loam, silt loam, and clay loam, reflecting the dominant particle size within the loam. Loams are favored for cultivation and horticulture due to their balance of drainage, nutrient availability, and workability. Management practices such as adding organic matter, minimizing erosion, and maintaining soil cover help sustain loam’s productive qualities.