Loam is a special kind of naturally occurring soil, and is considered ideal for gardening and agricultural uses because it retains nutrients well and retains water while still allowing excess water to drain away. It is composed of about 40–40–20% concentration of sand-silt-clay, respectively. Loam soils generally contain more nutrients, moisture, and humus than sandy soils, have better drainage and infiltration of water and air than silt and clay-rich soils, and are easier to till than clay soils.