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Note
1 * Disclaimer: Mention of names or commercial products in this document does not imply recommendation or endorsement by the U.S. Department of Agriculture.
2 Evolution of the Soil Health Movement
Douglas L. Karlen, Mriganka De, Marshall D. McDaniel, and Diane E. Stott
Soil Health, during the second decade of the 21st Century, has become a familiar term to both rural and urban audiences. Some may think the concept is new, but as outlined herein, the projects, workshops, books, and all other activities addressing this topic are built on a solid foundation reflecting numerous research, education, and technology contributions such as soil conservation, soil condition, soil tilth, soil carbon management, soil quality, soil security, or simply prevention of soil degradation. We have broken the evolution of soil health activities into four stages: (i) pre‐20th Century contributions, (ii) soil tilth and conservation activities between ~1900 and 1970, (iii) introduction and initial soil quality activities, and (iv) acceptance, promotion, and adoption of soil health per se. Recognizing some contributions have been missed, we hope the presentation will provide a reasonable foundation for many different readers.
Introduction
As the second decade of the 21st Century ends, the term “soil health” has become an accepted phrase, embedded globally in technical and non‐technical writings. Federal and state government, non‐government organizations, foundations, institutes, college and university curricula, public‐private‐partnerships, and numerous other entities have embraced the concept and thus embedded the term into the vernacular of many groups (Figure 2.1). For those who have spent recent decades striving to encourage adoption of soil health principles and the management practices required to implement them, global recognition and acceptance of soil health is gratifying, but we fully acknowledge that our small and humble contributions were built on foundations laid by many before us. Some may regard the concept as new and unique, but soil health per se evolved from several soil management focus areas including soil condition, soil tilth, soil management, soil conservation, soil care, soil quality, soil productivity, soil resilience, soil security, and soil degradation.
Figure 2.1 An exponential increase in the use of soil quality and soil tilth in published literature.
(Developed by M.D. McDaniel using https://books.google.com/ngrams [Michel et al., 2011]).
Advocates for the care and wise use of soil have been warning humankind since before the common era (BCE) that soil (a.k.a. Land) is the foundation for everything we do or share (e.g., food security; water infiltration, retention and release; environmental buffering; biodiversity). Many pioneers, including H. H. Bennett who in response to the American Dust Bowl and many other improper soil management decisions successfully established the U.S. Soil Conservation Service (SCS), dedicated their lives to protecting and improving soils (Bennett, 1950). But, without question, something unique happened during the 1970s and 1980s (Figure 2.1) that spurred interest and resulted in an exponential increase in the words soil quality and soil health in titles, keywords, and abstracts from which literature search databases are built.
We cannot identify any single event (e.g., The Dust Bowl) or explain why the importance of soil resources was finally recognized and publically discussed. Perhaps, it was the establishment of “Earth Day” in 1970 which significantly increased awareness of unintended environmental impacts associated with post‐World War II industrial developments (e.g., non‐point pollution; surface‐ and ground‐water contamination and depletion; wind‐, tillage‐ and water‐induced soil erosion; acid rain; increased emission of greenhouse gases). None‐the‐less, soil resources, some 40 years after the U.S. Dust Bowl, were once again being recognized as fragile and in need of appropriate care and management to sustain them. During that era, our now deceased mentor, colleague, and friend, W. E. (Bill) Larson, often described soil as “the thin layer covering the planet that stands between us and starvation” (Karlen et al., 2014a). This quote parallels writings by two other soil science pillars whom we suggest indirectly helped lay a foundation for soil health. The first is W.C. Lowdermilk (1953), who summarized his personal experiences in 1938 and 1939 in an often‐reproduced publication entitled "Conquest of the Land through 7,000 Years." His writings began by recognizing that human civilizations literally wrote their records on the land. He used those experiences to help raise public awareness of soil erosion problems occurring within the United States and globally. The second is Hillel (1991) who in his book “Out of the Earth: Civilization and the Life of the Soil” included a treatise in which Plato has Critias deliver a proclamation comparing degraded land and soil resources to an abandoned, emaciated person.
Science‐based principles influencing or even controlling overall soil health and the critical functions healthy soils provide for humankind can be traced to Aristotle or van Helmont, who provided some of the first insight and understanding of how plants obtain their nutrients from soils. Carter et al. (1997) quoted Columella, a prominent writer about agriculture within the Roman Empire,
