This week in lecture we discussed the different definitions of soil. The engineering field described soil as, ‘”the solid material that can be removed without blasting.” Soil is biologically defined as, “unconsolidated mineral or organic matter on the surface of the earth that has been subjected to and shows effects of genetic and environmental factors.” In over 8 million hits on a Google search for “soil definition,” many websites offered their own words on exactly what soil is. The Organization for Economic Cooperative and Development Statistics glossary gave a simple, physical definition that, “Soil is the loose and unconsolidated outer layer of the earth’s crust, made up of small particles of different sizes.” The Natural Resource Conservation Service gave a blanketing, multi-part definition that encompassed many feilds of study: ” soil – (i) The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants. (ii) The unconsolidated mineral or organic matter on the surface of the Earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time. A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.” Even Merriam-Webster gives a couple definitions as verbs and nouns that include an agricultural definition as well as some synonymns such as “corruption” and “sewage.”
If you were to go to the library and pick up a couple books that contained information on, say, photosynthesis, there would not be much discrepancy on exactly what photosynthesis is, what elements or compounds are part of it, where and in what organisms it occurs, etc. The reason why soil has so many definitions is because soil is used in so many ways. Geologists will consider soil in a very physical sense, and define it in a physical manner. A biologist will see soil in terms of its nutrients for organisms as well as the organisms that soil is home to. An engineer, as the class definition alludes to, may be occupied with movement of the earth’s crust, therefore defining soil as a very movable component. An agriculturist would look at soil as containing nutrients and some organisms vital to the growth of crops. Even Merriam-Webster, giving a more social definition, would define soil like its frequently and erroneously used counterpart, dirt, in that it would be like sewage.
But, these are just words. Soil isn’t able to name or describe itself. Soil is, however, defined by the nature around it. The five factors that define soil are climate, organisms, topography, parent material and time. Soil that is in coastal North Carolina will be different that that in the mountain of Chile according to the amount of precipitation and temperature. Soils in warm humid region are more likely to lose their soluble nutrients. In warm, dry regions, salts may render the soil unable to hold plant life. The organisms greatly differ in various soils and organisms will also differ in their impact of the soil. Certain types of fungi and bacteria aid in plant processees and also earthworms help to aerate the soils. Topographical characteristics such as incline affects the amount of erosion that will occur in an area. The color and characteristics of soils are determined by parent material, which over time, erodes into soil pieces classifed as sand, silt or clay.
There are many ways that we use soil. From use and observation we can define our soils. But in actuality, it is not our definition of what soil is that makes soil, it is many other physical, chemical, biological processees on our earth that make soil what it is.
“Environments are not just containers, but are processes that change the content totally.” -Marshall McLuhan