Biota and Soils

Does Slough Mud Qualify as Soil?

Slough mud with its myriad organisms does qualify as soil, but it qualifies more so when it exists in an undisturbed state, before being slurried as a bucket of mud. While the conventional idea that soil forms subaerially on land has a long tradition, the idea that it might also form underwater has long been espoused, since the early 19th century. In recent years, terms and expressions such as submerged soils, submarine soils, ocean soils, freshwater soils, and subaqueous soils follow these views and are now garnering validity for such soils. However, while the early and later observers used the word soil, they more likely were thinking about its uppermost part where most organisms dwell—the part more recently conceptualized and named “soil biomantle.”

What is Soil?

Views and paradigms of soil—including what soil is—have been in flux, not only for agronomists, soil scientists, and pedologists but also for archaeologists, biologists, ecologists, foresters, geographers, geologists, oceanographers, and many others. Such a community of scientists must deal with a concept of soil that covers a wide agenda—an ecologically based one that embraces both applied and pure science research, transcends multiple disciplines, and encompasses all environmental contexts. Those who study soil or who work with it in any way must come to grips with understanding the central pathways of soil formation. A definition of soil that is compatible with such an agenda is a necessary step.

In advance of these tasks—to better accomplish them and to gain some understanding of the entrenched mind-sets that might resist such a broadened approach to soil—we must briefly examine the gardener-farmer-agronomic practical traditions that underlie the conventional views of soil and that link traditional soil science dubiously to pedology, the two disciplines that claim soil as an object of study. Soil science has a broad societal practical agenda that includes crop yields, soil amendments (e.g., fertilizers, pesticides, herbicides, fungicides), plant diseases, soil survey, soil classification, soil genesis, soil quality, soil and natural resources conservation and management, extension/outreach services, and so on. The domain of pedology is narrower and less practical, with a focus on a scientific understanding of how soil forms, its properties, its depth (thickness), its ecological functionality, and other aspects—subtle though very basic distinctions.

...