表土

表土 是泥土的最高層, 通常在頂部15至20厘米。他是泥土中含有最多有機質合微生物的地方。地球上的多數生態活動進行的地方，植物也在此吸收養分，而它們的根大部分也長在這裡。 Topsoil can be measured as the depth from the surface to the first densely packed soil layer known as hardpan.

A major environmental concern known as topsoil erosion, occurs when the topsoil layer is blown or washed away. Without topsoil, little plant life is possible.

A variety of soil mixtures are sold commercially as topsoil, usually for use in improving gardens and lawns.

As one of the layers of soil on the Earth's surface, topsoil is sometimes referred to as the A horizon.

Topsoil also hosts a ton of bug life.