Earthworms Boost Crop Yields And Protect Plants From Microplastics

Earthworms are well-known for their ability to enrich and improve soil. Yet, their precise impact on plant growth had remained a mystery. Now, two groundbreaking studies have found that these creepy crawlers not only boost crop yields but also protect plants from harmful microplastics.

In late 2023, a research team from Colorado State University (CSU) reported that earthworms are responsible for 6.5 percent — or as much as 140 million tons — of global food production annually. This is comparable to Russia's annual grain harvest, which is the world's fourth largest.

CSU's Steven Fonte and his team arrived at this conclusion after a comprehensive study. They surveyed earthworm populations, soil properties, and crop yields from around the world. The researchers focused on four grains — rice, maize, wheat, and barley. They also measured the harvests of legumes like soybeans and peas.

The team found that the earthworms' impact was significant in developing countries. For example, they helped increase grain yields by 10 percent in Sub-Saharan Africa and 8 percent in Latin America. Fonte and his team believe farmers in these regions likely lack easy access to fertilizers and pesticides. This makes them more reliant on earthworm-rich organic matter, such as manure and crop residues.

"Earthworms are contributing a lot in these areas where we have fewer chemical inputs," Fonte said. "If we manage our soils in a more sustainable way, we can better harness or leverage this biodiversity and produce more sustainable agroecosystems."

Earthworms help plant growth in several ways. Their burrowing creates channels that loosen and aerate the soil. This allows water to drain from the surface and be stored underground. The earthworms' constant movement helps churn the soil's organic matter, making the nutrients more available to plants.

In a separate study, scientists at Japan's Nankai University found that earthworms can also protect plants from microplastic pollution. The researchers tested this by placing tomato plants in soil contaminated with tiny plastic particles. They found that when earthworms were present, the plants thrived despite the pollution. They were also able to repel common plant-eating bugs. The scientists revealed their findings in September 2024. They believe that earthworms help boost the tomato plants’ immune systems. This makes them more resilient to environmental changes.

Resources: Sciencealert.com, Phys.org, science.org, thecooldown.com