By Lisa Boonstoppel-Pot

This past Spring, on a beautiful evening after the sounds of the day had faded away, Carl Brubacher of Carlotte Farms Inc. near Arthur stood in the midst of a field of corn residue and listened to the earthworms.

“You could hear them,” he says, excitement creeping into his voice. “You can shine your phone on the field and you’ll see them grabbing at corn leaves with their mouths. They have no idea how big the leaves are so they keep working away at it and you can HEAR it, literally millions of them working away...it’s so neat.”

Since posting a picture of a shovel of soil featuring a count of 80 earthworms, Brubacher has become known as the “earthworm guy”. His slogan is “Earthworms are Nature’s Plow”.

He isn’t the only one. Earthworm excitement is a real thing. And this year’s wet spring has some farmers concerned how their “ecosystem engineers” are thriving.

“Given this wet year, farmers have struggled with timing to plant crops and they’ve had to grit their teeth and march through. There has been more compaction and compaction is hard on worms,” says Anne Verhallen, a soil specialist with OMAFRA. “However, there has been less tillage because the weather did not cooperate so farmers settled for a rougher seedbed than they normally would. So there has been a bit of balance.”

Chatting with Verhallen and  Sebastian Belliard, a soil specialist with OMAFRA in Eastern Ontario and you’ll find yourself wanting to count worms. More than 20 worms in a shovel and that’s cause for celebration! Read articles from worm expert Odette Menard of the Quebec Ministry of Agriculture plus the works of Charles Foster’s Being a Beast and eating earthworms to simulate living as a badger and you start to sense that earthworms have a fan base. However, farmers that use a lot of tillage are unlikely to be part of the earthworm fan club.

“Tillage has a big impact on earthworms,” says Anne Verhallen, a Soil Management Specialist with OMAFRA. “They are less affected by shallow tillage and more affected by heavy disking and plowing.” Especially the deep burrowers.

Essentially, farmers are likely to find three kinds of earthworms in their fields, writes Odette Menard – epigeic, endogeic and anecic. 

Epigeic worms are the surface dwellers living in the crop residue for 90 to 150 days. They don’t make tunnels so much as live and feed on crop debris. Visually, they are often bright red and reddish-brown.

Endogeic worms are the topsoil dwellers, getting a little deeper, living and feeding in the topsoil. They can live 150 to 210 days and are often pale colours of grey, pink, green or blue. They make horizontal tunnels through the soil.

Anecic worms are the deep burrowers that live the longest, about 500 days! They have long tunnels from which they rise at night to feed on crop residue. These are also the worms that create middens, those little mounds of dirt on top of their holes which serve as rooftops. “They act like an air conditioning unit keeping their burrows cool,” says Verhallen. Anecic earthworms are recognizable by their dark red or brown heads and paler tails.

Each kind of worm adds value.  Soil containing all three kinds of worms means your soil is doing well. Yet it’s the anecic or deep burrowing worms which are really indicative of soil health says Sebastian Belliard.

“They are more sensitive to soil management than topsoil worms,” he says. “They make their homes in all kinds of soils though they don’t do well in very shallow, very wet or very coarse, sandy soils. But imagine if someone comes along every year and destroys your home. Well, you would move on. This is, of course, an analogy for what tillage does. Tillage disturbs their burrows and breaks them up and can kill worms.”

Belliard says the deep burrowers are really “eco-system engineers of the soil” in that they alter the landscape for other creatures.

It’s what they do for the crops, though, that makes them invaluable.

Those vertical worm holes become important points of entry for quick water infiltration.

Earthworms improve soil porosity, increasing the exchange of carbon dioxide (which needs to leave the soil) and oxygen (which roots need for growth). Soil porosity also reduces the effect of compaction from heavy equipment.

Belliard explains that worm holes are lined with organic matter which adds nutrients to the soil. Worms leave a mucous behind as they travel and this mucous makes worm tunnels stable. Crop roots then “race through these tunnels” searching for moisture and nutrients.

“Earthworm castings are eight times more fertile than bulk soil,” says Belliard.

According to a PennState article on earthworms, a typical earthworm population can “easily” consume two tonnes of dry matter per acre per year. That’s a lot of crop residue transformed into earthworm casts which contains more nitrogen, phosphorous, potassium and calcium content that surrounding soil. Soil castings also make available essential soil micronutrients such as zinc and boron.

Moreover, some earthworms eat harmful nematodes.

Belliard and Verhallen say they have been talking about earthworms for years but it was when they started digging holes and doing earthworm moulds that people could “see” how deep and productive earthworms are.

“I have done worm counts for 20 years or longer but it wasn’t until we started doing the latex moulds, that I really got the complexity of what was going on in the soil,” admits Verhallen.

The moulds are made by pouring liquid latex into the soil. They are left for three weeks to allow the latex to set and are then carefully excavated to uncover a latex form that resembles a jellyfish with tendrils going off in all sorts of directions.

Belliard often digs holes for farmers to get a visual.

“My champion earthworm burrowed a metre and 15 centimetres into poorly drained soil,” says Belliard, who takes farmers on worm-counting forays into their fields. “That was an eye opener for those farmers and what I really remember from that experience is how one farmer said, ‘Those worms work so hard for me, maybe I should do a bit to help them out.’”

“Yes”, exclaims Brubacher! This is exactly what he wants to hear. He thinks as farmers, we have to work at changing what we perceive as “good” soil.

“It seems locally that we really like black soil ... that we need a whole lot of fluffy topsoil to plant into,” says Brubacher. “I tell you, I really struggle seeing a plowed field. I like to see a corn field with residue in between knowing that worms are working away.”

Tillage is the enemy of earthworms, confirms almost every earthworm lover.

“For worms, you want residue on top. If we put that residue into the soil, the worms will not touch it. They want it on top to pull it down and process it,’ says Brubacher. “THEY put the corn stalks through them.”

In accordance with his quest to champion earthworms, the Brubachers have gone largely minimum tillage, using a CurseBuster, a passive vertical-tillage tine tool which goes eight inches deep into the soil, fracturing it,  without disturbing or relocating the soil. “It doesn’t hurt the earthworms. It enhances them,” says Brubacher.

“It’s not the earthworm pickers. It’s not the seagulls. The biggest destroyer of earthworms is tillage,” says Brubacher.

Belliard agrees. “Less tillage is key but I am hesitant to recommend no-tillage across the board,” he says. “Conditions are so variable and the equipment farmers have is so variable. I hesitate to tell people this is the only way. But for sure, less soil disturbance is better for soil organisms.”

If tillage is part of a farmer’s cropping plan, the use of cover crops can go a long way to making life better for earthworms.

‘“The more thi ngs that are living above the ground, the more things are living below the ground,” says Belliard. “But there are still trade-offs. Cover crops take more management and unpredictabe spring conditions can make them difficult to manage according to plan.”

Such as the Spring of 2019. How did all that rain affect the earthworms, anyway?

“If it is too wet for a crop to grow, it is too wet for worms. They will drown,” says Verhallen. However, while it has been very wet in Ontario this spring, fields have generally been more waterlogged than flooded. “Waterlogged is not good for the earthworms but they will regroup and come back as long as the rest of their habitat is undisturbed.”

Good crop rotation, the use of cover crops, manure application and using compost when possible all contribute to increasing earthworm populations.

In particular, earthworms prefer perennial crops and deep roots. An ideal rotation for earthworms is a hay crop including alfalfa (which has deep roots) rotated with soybeans since earthworms love soybean residue.

Encouraging a thriving population of earthworms can be more challenging in sandy soils because of its abrasive qualities. Worms need their skin to breathe. Interestingly, earthworms are not viewed with delight by all lovers of farm, field and forest. Verhallen says OMAFRA and the Ministry of the Environment have “polite conversations” about earthworms.

“Earthworms are great things and have their place in fields and gardens. Where we have problems is when people go fishing near forest areas and dump their bait buckets where they should not be,” she says.

Earthworms can be terribly destructive in forests, eating forest litter which is essential for the understory population. Also, there aren’t many predators in forests to control them.

Fortunately, worms are not expansive travellers. They only move about six to 10 feet a year. Also, their populations tend to be inconsistent, with higher populations around old farm buildings and orchards.

Foresters are really worried about imported worms, such as the various species of Asian jumping worms, a group of large worms named as such because when touched, they wriggle violently in a snake-like motion, sometimes even leaping into the air or detaching their tails trying to escape. These worms don’t really burrow. They stay on the surface, often in leaf piles and consume more plant matter than other worms. The result is rather than enriching the soil, they transform it into a field of soft, dry soil pellets sort of like ground coffee. Asian jumping worms can be identified by their dark grey-brown colour and lack of slime.

One last interesting and super-weird fact about earthworms is their taste. After our interview, Belliard forwarded an article by Charles Foster, a Brit who lived as a badger, otter, fox and stag for a year. Since about 85 per cent of a badger’s diet consists of earthworms, Forster was compelled to sample many an earthworm in his travels. Not surprisingly, he said “earthworms taste of slime and the land.” However, they have a very distinct terroir based on where they feed. “You can suck off the slime and you’ll find that Chambly slime, at least in the Spring, is lemongrass and pig shit. The slime of the weald is burning rubber and halitosis. The tastes vary with the seasons...”

Certainly, this is next-level for earthworm enthusiasts who might realistically prefer to keep worms doing what they do best: transforming field soils into a palatable mix for hungry crop roots.◊