topsoil

Topsoil is the uppermost layer of soil, typically containing the organic material where plant roots grow most actively. This layer is crucial for agriculture and is the part farmers turn over when plowing. Soils are distinguished by distinct layers called horizons, formed by water and living organisms. Topsoil is rich in organic matter and teeming with microorganisms that recycle essential elements like carbon and nitrogen.1234

The composition of topsoil, including its grain size (clay, silt, sand) and porosity, influences its ability to hold water, air, and nutrients. Factors like parent material, topography, climate, organisms, and time all contribute to soil formation. When topsoil is removed, the underlying subsoil is exposed, increasing the rate of soil erosion.5673