By Stephanie Frischie, Agronomist/Native Plant Materials Specialist, The Xerces Society
A handbook and online course for supporting soil invertebrates and soil health
Fig 1. The cover of Farming with Soil Life implies the relationships between people, agriculture, soil, and soil animals (The Xerces Society).
Healthy soil is living soil: microbes, roots, tiny animals, little animals, and bigger animals living within and among mineral particles, pore spaces, water film, and organic matter. Interest in soil health has sparked a long overdue awareness of soil microbiology and strategies to encourage beneficial soil fungi and bacteria.
However, the diversity of soil animals (typically invertebrates) and their essential roles in creating and sustaining soil health is still largely overlooked. Xerces’ Farming with Soil Life handbook was written with the goal to make awareness and understanding of soil invertebrates more accessible, to offer methods for observing and identifying soil invertebrates, as well as an overview of how management practices affect the soil animal community.
The handbook was initially written and published by Xerces in 2021, through funding from Northeast SARE*. In 2023, national SARE and Xerces made a few minor content changes, and added it to the offering of SARE books. It is organized into seven chapters:
- Chapter 1: Our Living Soil: An Introduction;
- Chapter 2: Soil Health;
- Chapter 3: Observing Soil Life;
- Chapter 4: Farming Practices that Can Put Soil Health at Risk;
- Chapter 5: Farming Practices that Support Soil Health;
- Chapter 6: The Life in Soil; and
- Chapter 7: Final Thoughts.
Chapter Six, The Life in Soil is the bulk of the handbook – profiles of 72 soil animal groups (and one protozoan) are featured across 81 pages and illustrated with 215 images. These animals include mesofauna such as rotifers, tardigrades, nematodes, springtails and thrips to the larger macrofauna of pill bugs, centipedes, spiders, cicadas; and many types of flies, beetles, bees, wasps and ants.
Fig. 3 Ground beetle adults live on the soil surface and eat other invertebrates as well as seeds. The larval life stage of ground beetles dwell in the soil and are predators of soft-bodied animals like caterpillars, rootworms, slugs, and snails. (Sarah Foltz Jordan/The Xerces Society)
The profiles are organized roughly by body size and taxonomy. Subtitles in the page margins guide the reader through learning and finding animals of interest; there is also an at-a-glance index on the final page of the book that makes it easy to flip directly to a group of interest – fireflies for example.
Yes, fireflies! As with many soil invertebrates, the larval stages of most firefly species are soil-dwelling, where they are predators of their main food sources of slugs, snails and other soft-bodied animals. Additional information in the profile for fireflies (page 88, if you’re interested to read for yourself) includes that there are around 170 species described from the United States, and roughly 2,200 species globally. The larvae overwinter under bark or by burrowing in soil. Fireflies pupate in soil, under rocks or in decaying plant material near the soil surface. Insecticides, soil drainage and soil disturbance are harmful to fireflies. Reducing or eliminating insecticides, minimizing soil disturbance and protecting moist areas of open soil mixed with vegetation are ways to create or improve habitat for fireflies.
Soil is right beneath our feet, our paths, our roads, our buildings but despite the proximity, the life in soil is somewhat inaccessible. We need to dig and probe and uncover to start to see and understand soil ecology. In the chapter, Observing Soil Life, the handbook explains how to make and use simple pitfall traps or Berlese funnels to collect and observe soil animals.
Recently at my own home, I’ve been working on transplanting native plants from containers into the ground. As I depot the plants, I often get a quick glance at a variety of soil invertebrates – especially pill bugs, centipedes, and mites, but I’ve also found this a pretty easy way to observe diplurans and occasionally I come across a firefly pupa, which always feels like a special treat.
Fig 3. A firefly pupa that the author observed on top of soil while depotting plants (Stephanie Frischie/The Xerces Society).
Hopefully this post has further stimulated your curiosity and interest in soil animals. The Farming with Soil Life handbook is available as a free PDF from the Xerces website and hardcopies are available for purchase from SARE.
As a companion opportunity to the handbook, Xerces offers a series of online short courses about Farming with Soil Life. Past recordings are in a play list on Xerces YouTube. I’m delighted to highlight that Isabelle Jenniches, founder of the New Mexico Healthy Soil Working Group will be the guest presenter at the next online course, held July 25, 2023, from 9:00AM- 1:00PM Mountain time**. Isabelle will talk about her experience co-creating soil health legislation in New Mexico and how others can participate in shaping conservation policy in their communities. From Xerces, Jennifer Hopwood and I (co-authors of Farming with Soil Life) will present modules on basic soil science, soil animal profiles, observation methods and best management practices. Please see this page for the link to register for the free course.
* This material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, through the Northeast Sustainable Agriculture Research and Education program under subaward number ENE19-158-33243.
Additional funding from Organic Valley, Blooming Prairie, and Xerces Society members.
** This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number G185-21-W7903 through the Western Sustainable Agriculture Research and Education program under project number PDP20-003. USDA is an equal opportunity employer and service provider. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.