Fundamentals of soil characterization

Authors: WEINDORF, DAVID - Georgia Southern University; Acosta-Martinez, Veronica

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 6/30/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soils provide humanity with food, shelter, clothing, filtration of water, and a litany of ecosystem services across the planet. In recognition of the global importance of soils, humanity has long sought to characterize soils in any number of ways (e.g., physically, chemically, biologically, taxonomically) and make interpretations/suitability as to its optimal use (e.g., agronomic production, septic drainage fields, construction material, engineering stability, etc.). Today, with the combined effort of scientists across the world, advanced instrumentation provides multi-parameter characterization, high throughput DNA sequencing, and various “omics” techniques with improved precision and lower limits of detection to evaluate soils. Scientists from Southern Georgia University and USDA-ARS in Lubbock TX gathered a book chapter titled “Fundamentals of Soil Characterization” for the book effort titled “Unlocking the secrets of soil: Applying artificial intelligence and sensor technologies for sustainable land use and soil management”. The main goal of their chapter is to provide an overview of fundamental measurements for soil physical, chemical, and biological properties that are critical in soil characterization and it will provide trends generally observed across climatic zones and soil types.

Technical Abstract: Soils provide humanity with food, shelter, clothing, filtration of water, and a litany of ecosystem services across the planet. In recognition of the global importance of soils, humanity has long sought to characterize soils in any number of ways (e.g., physically, chemically, biologically, taxonomically) and make interpretations/suitability as to its optimal use (e.g., agronomic production, septic drainage fields, construction material, engineering stability, etc.). Indigenous people have long made basic determinations on soil/land use suitability in support of agricultural sustainability, long before modern scientific advancements. Early forays into formal soil characterization began with Albrecht D. Thaer and Justus von Liebig. The former evaluated humus and soil texture as variables in soil fertility while the latter determined that soils release nutrients for plant uptake, popularizing the “law of the minimum” noting that plant growth is constrained by the nutrient in which it is most deficient. Advances by Vasily V. Dokuchaev led to characterization of the Russian Chernozem whereby early forays were made into the factors of soil formation. Hans Jenny (1941) is later credited with refinement of the factors of soil formation. Significant advancements in United States soil science were made by Eugene W. Hilgard (1833-1916), Milton Whitney (1860-1927), Hugh H. Bennett (1881-1960), George N. Coffey (1875-1967), Charles E. Kellogg (1902-1980), and Guy D. Smith (1907-1981). Notably, in contrast to the World Reference Base for Soil Resources identified by the International Union of Soil Scientists (IUSS Working Group WRB, 2022), US Soil Taxonomy (Soil Survey Staff, 1999) relies heavily on quantitative limits (e.g., morphological, chemical, physical) to distinguish diagnostic subsurface horizons and features. In support of soil survey efforts across the United States, soil survey laboratories of the US Department of Agriculture at Beltsville, MD and Riverside, CA preceded the contemporary soil characterization laboratory at Lincoln, NE. As new technologies were developed in the mid-late 20th century, the characterization of soils advanced concomitantly. Many such advances involved the development of standard, laboratory-based techniques and use of instrumentation that replaced qualitative descriptions (e.g., flame photometry, solubridge, colorimetry, granulometry, gas chromatograph, etc.). Near the end of the 20th Century, in the 1990s, focus was given to evaluating a suite of soil biological, chemical, and physical properties together to provide an index of soil quality or the capacity of the soil to function within its ecosystem boundaries, represented by key USDA-ARS scientists John Doran, Doug Karlen, Diane Stott, Brian Wienhold, and Cynthia Cambardella. The main goal of this chapter is to provide an overview of fundamental measurements for soil physical, chemical, and biological properties that are critical in soil characterization and trends generally observed across climatic zones and soil types.