The Earth's interior is composed of four layers, three solid and one liquid ... It is the familiar landscape on which we live: rocks, soil, and seabed. It ranges from about five miles (eight ...

All plants require 17 elements to complete their life cycle, and an additional four elements have been identified ... plants derive the remaining 14 elements from the soil or through fertilizers ...

The iron and aluminium oxides collect in the 'B' horizon where the iron oxides can accumulate to form a thin layer of hardpan, which impedes drainage through the soil. Illuviation is the process ...