REVIEW: The Earth Moved
Going underground
This witty and informative book scratches below the surface to reveal the fascinating world of earthworms.

Reviewed by Dan Sullivan

April 1, 2005: Amy Stewart's The Earth Moved: On the Remarkable Achievements of Earthworms is a must-read for all farmers, gardeners, budding oligochaetologists, and anyone curious about life underfoot.

Stewart, an avid organic gardener and vermicomposter herself, has a smart and quirky style that makes this “everything you ever wanted to know about terrestrial worms” tome as fun to read as it is informative.

The author tracks down Charles Darwin, recently returned from his famous voyage on the Beagle, discovering—in the unlikely world of his uncle's backyard—the awesome power of the lowly earthworm and its singular role in creating “vegetable mould” (the contemporary term for the rich, uppermost layer of fertile soil).

When Darwin wrote—in the last published work of his life—that earthworms were essentially nature’s plow and that an acre of good garden soil might contain 50,000 earthworms (we now know that figure to be closer to 1 million) yielding 18 tons of castings, or earthworm manure, annually, his contemporaries scoffed, just as they had initially doubted his evolutionary theories, Stewart tells us.

As undaunted as Darwin himself, Stewart sets out—through keen observation, interviews and research—to make her case for the earthworm’s greatness.

“Over the last one hundred years, earthworm scientists…have come to quantify what farmers have always known: that worms, through their actions, substantially change the earth,” she writes. “They alter its composition, increase its capacity to absorb and hold water, and bring about an increase in nutrients and microorganisms. In short, they prepare the soil for farming.”

And that’s not all, according to Stewart (and Darwin). Earthworms are also capable of making complex decisions, such as selecting the precise size and location for leaves and twigs when constructing their burrows.

Another useful fact you will pick up on this subterranean sojourn is that—as far as your farm and garden are concerned—different types of earthworms are best suited to different types of activities. Red wigglers (Eisenia fetida) for instance, are epigeic worms, living a nomadic life in the topsoil. They have relatively short lifespans and multiply rapidly to match the available food source, making them a great choice for your worm bin or compost pile. Anecic worms like nightcrawlers (Lumbricus terrestris), on the other hand, live up to six years and build permanent vertical burrows deep into the soil. These are a poor choice for captivity.

Ah, the rhizosphere, that favorite universe of organic gardeners everywhere. It’s here, says Stewart, where you’ll find endogeic worms, little yellowish-brown (sometimes gray or slightly pink) creatures that rarely make it to the surface. Precisely because they lie low, Stewart tells us, many farmers choose these when inoculating their soil with earthworms (because they are less likely to be disturbed by cultivating activities).

With utmost sincerity, Stewart laments that she’ll probably never get to see a giant earthworm since many species—such as Oregon’s 3-foot Driloleirus macelfreshi—are becoming extinct even as they are being discovered.

Readily admitting she's not a scientist, Stewart does an excellent job of conveying her sense of wonder and discovery as she progresses from somewhat reservedly taking that first little red wiggler out of the backyard bin she’s kept for years and watching it slither across her palm, to a more intimate relationship with her subject.

“I pulled my glove off and ran a finger along the worm’s back, from head to tail. It stretched as I touched it, lengthening each segment under the pressure of my finger. Still, it didn’t seem to be trying to escape, just extending itself. I stroked it a few more times, slowly, guessing that a faster stroke would only harm it.”

If that’s not enough to get the earth moving, how about this: a single earthworm has both sets of sexual organs and reproduces by lining up its body with a partner so the ‘he’ parts match up with the ‘she’ parts.

If America is a great melting pot aboveground, Stewart reveals, a similar mixture is going on below. Most garden variety earthworms, we learn, hail from somewhere else. And ever-more-rare native species are being displaced by habitat destruction as well as by competition from non-natives.

Of particular interest to farmers is the fact that many of these non-native species—such as nightcrawlers, red wigglers and field worms (Aporrectodea caliginosa)—arrived in North America with early European settlers via “the soil of potted plants, the ballast of ships, the hooves of horses, and the wheels of wagons. Whether they came as stowaways or invited guests, there is no doubt that foreign species of earthworms…came west with settlers and helped turn the already rich valleys and plains of the Midwest into some of the best farmland in the world.”

And how are these little pioneers faring?

“Over the last few decades, earthworm censuses have found over a million worms per acre in Geneva, New York; Frederick, Maryland; and La Crosse, Wisconsin."

Ironically, as Stewart reveals, just as earthworms spent the past couple of centuries helping to turn the earth and increase the microbial community that fosters healthy crops and fertile soil, these miracle workers are also helping to clean up the pollution wrought be a half-century of chemical agriculture.

In fact, we learn, it was none other than Rachel Carson herself “who reported that worms have an amazing ability to absorb whatever is in the soil, and they were able to take up huge concentrations of DDT and still live.” Then there’s their use for processing biosolids in state-of-the-art sewage treatment plants. The list goes on.

Public Servant No. 1? Stewart makes a good case for it. Read “The Earth Moved” and you may think so, too.