Typically, if soil gets much attention from the general public, it is simply for how well (or poorly) plants grow in it. Soil science—an incredibly rich, complex, and multifaceted academic discipline—has long recognized that Earth’s soils are a dynamic interaction of physical, chemical, and biological properties.
Our understanding and thinking continues to change. Farmers, conservationists, scientists, and others fascinated by soils have started pushing us all to ask questions about what lives in the soil. For the first time, there is a nationwide conversation about the paramount importance of soil biology.
It turns out this biology question is key to many environmental and economic questions of our time. Increasingly, we understand that healthy soils are productive and resilient, ultimately sustaining abundant crops with fewer costly inputs down the road. For reasons that we are just beginning to understand, the biology of certain soils can also suppress plant diseases, much in the same way a healthy gut biome in people might help prevent human diseases. There’s also mounting evidence that we can harness the incredible root systems of plants and their microbial allies to store vast quantities of atmospheric carbon dioxide in Earth’s soils at rates that could help offset human-generated greenhouse gas. And, as we continue to face a striking global loss of wild plants and animals, we are becoming more aware that soil is part of the fundamental ecology of all species—it provides a living platform for tigers and crickets, bacteria and bees, oaks and wildflowers, as well as the minerals that build not only the cells of those species but also our own.
These guidelines are our addition to the discussion on soil biology. It is impossible to tell the story of every living species connected to the ground beneath us. With that in mind, we have focused this guide on the diverse, often overlooked, and essential living species that we know best: the major invertebrates (macrofauna and mesofauna) found in temperate agricultural soils. There is a focus on North America in the groups of organisms and the soil health practices that are covered, but many groups are present in these soil types around the world, and the same management principles apply. Larger soil animals, such as ground beetles, woodlice, and springtails, and their many companions, have received less attention than soil microbes in recent years. We hope this publication helps fill that gap in our understanding and appreciation of the life in the soil.
For further assessment of the presence of predatory organisms in the field, please refer to our Soil Scouting Guide.