Earthworms Contribute To 140 Million Metric Tons Of Food Production Yearly, Experts Say

Earthworms are key contributors to global food production, accounting for around 6.5% of grain yield and 2.3% of legume production per year.

With these new estimates from the Colorado State University scientists, earthworms may account for as much as 140 million metric tons of food produced annually, which is roughly comparable to the number of cereal grains grown annually by Russia, the world's fourth-largest producer (rice, wheat, rye, oats, barley, maize, and millet).

"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 Steven Fonte, associate professor of agroecosystem ecology in the Department of Soil and Crop Sciences at CSU, and the study's lead author.

Earthworms established healthy soils

Earthworms help in the establishment of healthy soils by assisting plant growth in a variety of ways, including developing good soil structure, assisting in water capture, and assisting in the beneficial churn of organic matter, which makes nutrients more available to plants.

Other research has found that earthworms can help plants protect themselves against common soil diseases by facilitating the generation of plant-growth-promoting hormones.

According to some estimations, earthworms can enhance overall plant productivity by roughly 25%.

Earthworms' contribution to world food production was calculated by superimposing and analyzing maps of earthworm abundance, soil parameters, fertilization rate, and crop yields.

In the findings, earthworms had a greater impact on grain output in the global south, accounting for 10% of grain yield in Sub-Saharan Africa and 8% in Latin America and the Caribbean.

Earthworms are likely to have contributed more in such locations since farmers there have limited access to fertilizer and herbicides. Instead, they rely on earthworm-rich organic materials such as manure and agricultural leftovers to enhance the beneficial effect earthworms have on plants.

Experts are hopeful

Fonte believes soil biodiversity has historically been neglected, and he hopes that this study will draw greater attention to how healthy soils may have positive, tangible effects 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," he said. "This work highlights that potential."

Diana Wall, a professor in the Department of Biology and the science chair of the Global Soil Biodiversity Initiative, was excited by the data.

"This, to me, is a really clever, very data-rich paper," Wall said. "It's really impressive."

Experts believe that this study could be useful in future efforts to minimize drought and erosion. Earthworms, for example, can improve soil porosity, assisting in the beneficial uptake and retention of water.

Fonte cautioned that he and his colleagues are not pushing for earthworms to be transplanted into areas where they do not currently exist.

Rather, he thinks that this research will demonstrate how enhanced soil biology management in areas where earthworms already live has the potential to boost agricultural productivity and minimize our dependency on agrochemicals.

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