An Example Emphasizing Mass-Volume Relationships for Problem Solving in Soils.

Mass-volume relationships are a useful tool emphasized for problem solving in many geo-science and engineering applications. These relationships also have useful applications in soil science. Developing soils students' ability to utilize mass-volume relationships through schematic diagrams of soil phases (i.e., air, water, and solid) can help to facilitate cross-discipline problem solving efforts encountered throughout their careers. The objective of this article is to provide an applied example emphasizing mass-volume relationships and schematic diagrams for problem solving in soils. The example is taken from a study in restoration of an organic wetland soil. Drainage of organic soils results in a reduction of horizon thickness, termed subsidence, through shrinkage, loss of buoyancy, and oxidation of organic matter. Knowing the amount of subsidence that has occurred is important in restoration efforts, but is difficult to determine from conditions post-drainage at a given site. Scientists must make use of mass-volume relationship and inference to assess the amount of subsidence that has occurred. In this example, information about post-drainage and offsite horizon thickness, bulk density, and sand content are used to develop an estimate of the amount of subsidence. General information about the site is presented followed by assumptions used to develop the solution. The problem, assumptions, and step-by-step solution are divided into parts to facilitate use as a homework example, lecture example, or group problem solving activity. Questions and discussion points are presented to encourage student development of their own solution to the problem.