ABSTRACT
Land systems are those parts of the earth upon which the human species, and many other animal species, live and from which they extract most of their food and energy. One of the greater impacts of humans upon land systems is the creation of desert areas by misuse/abuse of land where the yearly water deposition borders on arid/semi-arid allocation. Land systems are composed predominantly of four subsystems: minerals, sedimentary strata, clays, and soil. The land systems are divided into strata including the solid iron-rich inner core, molten outer core, mantle, and crust. Sedimentary strata typically consist of mixtures of clay, silt, sand, organic matter, and various minerals. They may vary in composition from pure mineral matter to predominantly organic matter. Clays are defined by size, as are other inorganic constituents of the earth. The most important part of any land system is soil insofar as it is the medium upon which virtually all terrestrial organisms depend it for their existence.
