In a study recently published by Colorado State University, scientists have found that earthworms play a substantial role in the global production of grains and legumes.
According to the research, earthworms contribute to 6.5% of the worldwide grain yield, which is roughly equivalent to the annual cereal grain production of Russia, the fourth-largest producer globally.
“This is the first effort that I’m aware of that’s trying to take one piece of soil biodiversity and say, ‘OK, this is the value of it; this is what it’s giving us on a global scale,’” said study lead author Dr. Steven Fonte.
Earthworms promote healthy soils in different ways. They enhance soil structure, optimize water retention, and enrich the soil by churning organic matter, making essential nutrients more accessible to plants.
In fact, the presence of earthworms has been linked to a surge in plant productivity by an estimated 25 percent.
The research was conducted by Dr. Fonte, Professor Nathan Mueller, and Marian Hsieh, a doctoral student at CSU.
The team arrived at these figures by analyzing various data, including maps that highlight earthworm abundance, soil attributes, fertilizer usage, and crop yields.
One particularly fascinating revelation was the pronounced influence of earthworms in the grain production of the global south.
Earthworms contribute to 10 percent of the grain yield in Sub-Saharan Africa and eight percent in Latin America and the Caribbean.
It’s likely the earthworms contributed more in those areas because farmers there tend to have less access to fertilizer and pesticides, explained Dr. Fonte.
Instead, they rely more on earthworm-rich organic matter like manure and crop residues, which help stimulate the beneficial effect earthworms have on plants. “Earthworms are contributing a lot in these areas where we have fewer chemical inputs.”
Dr. Fonte noted that soil biodiversity has historically been undervalued, and he hopes this work will bring more attention to how healthy soils can have positive, tangible impacts on crops.
“If we manage our soils in a more sustainable way, we can better harness or leverage this biodiversity and produce more sustainable agroecosystems,” said Dr. Fonte. “This work highlights that potential.”
Dr. Fonte also noted that other recent research has shown that soils contain as much as half the world’s biodiversity, a significant increase from previous estimates of approximately 25 percent.
“Soils are just such an intricate habitat,” he said. “But there’s really been very few efforts to understand what that biodiversity means to our global crop yields.”
According to Dr. Fonte, insights from this study could also have implications in future efforts to mitigate drought and erosion. For example, he said, earthworms can improve soil porosity, aiding in the beneficial capture and retention of water.
The researchers emphasized that they are not advocating for anyone to transplant earthworms into places they do not already exist.
Dr. Fonte hopes this work shows how improved management of soil biology in places where earthworms already call home has the potential to enhance agricultural productivity and reduce our reliance on agrochemicals. He said the study marks an important first step.
“Soils are still this huge, big black box that we don’t fully understand,” said Dr. Fonte. “This work helps show that there’s a lot of opportunity that we’re just kind of ignoring. There are probably other soil organisms that are even more important, especially microbial communities.”
The research is published in the journal Nature Communications.
Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.