Pedologist Question:

Download Questions PDF

Soil is only found on the earth's surface. The depth of a soil depends mostly on how much rain falls on the soil, and how old the soil is. Some soils are only a few inches (or centimeters) thick - on mountains, in some deserts, and in arctic regions. Other soils can be more than 6' feet (two meters) deep. Though sometimes soils are deeper, we usually do not consider them as soil because roots of most plants are concentrated in the top 2 or 3 meters. Topsoil is usually the top 15 to 30 centimeters of soil. The subsoil then may go down to 2 or 3 meters.