The present study continues our x-ray photoelectron spectroscopy (XPS) or electron spectroscopy for chemical analysis investigations of silicate systems, particularly those in contact with biological materials. In the present case, the investigations are extended to a detailed analysis for a wide variety of soil samples extracted from different locations around the world. The samples were selected from relatively pristine sites, pressed into wafers, and were examined without further modification. All of the materials were insulators and therefore analysis required extensive use of the electron flood gun. Careful XPS chemical shift assignments have been achieved for many silicate minerals. These have been exploited in the present study along with the detailed XPS analysis of organofunctional groups rendered by Beamson and Briggs. As a result, a fairly detailed simultaneous nondestructive description is provided of the surface of both the humus and silt components of these soil samples. Substantial variations in the composition are demonstrated and questions are raised about our classifications of fertility
