ABSTRACT
Soil is a category of physical evidence that, like hair and fibers, is ubiquitous. And like hair and fibers, it is a category of trace evidence, even though it, too, is visible. What makes it trace evidence is how it is collected at the scene and analyzed in the laboratory, the latter requiring microscopic, instrumental, and biological testing methods to identify the various mineral, organic, microbiological, botanical, manufactured, and other biological components. Soil varies greatly throughout the world, and it forms for various reasons [2]. The following list was adapted from [2]
Parent material• : This is the material that forms the basis of soil. It can be bedrock, organic material, an old soil surface, or a deposit from water, wind, glaciers, volcanoes, and so on. Climate• : The environment changes from day to day, month to month, and season to season. This means that temperature, weather, wind, sunshine, and other environmental forces work on the parent material to change it over time. Biological material• : Plants and animals living in or on the soil affect decomposition of waste materials and how soil materials move around in the soil profile. The dead remains of plants and animals become organic matter which enriches the soil. Humans affect the soil through the use of fertilizers, construction, and manufacturing. Topography• : The location of soil can affect how climatic processes impact it. Soils at the bottom of a hill will get more water than soils on the slopes, and soils on the slopes that directly face the sun will be drier than soils on slopes that do not.
