Earthworms can reproduce in Mars-like soil

Researchers at Wageningen University introduced earthworms to pots of Mars-like soil featuring arugula plants and organic matter. Early results suggest the earthworms were able to successfully reproduce.

If humans are to establish permanent colonies on Mars, they'll need to grow their own food. Previous research has shown Martian soil can support crop growth. The latest research suggests the soil can also support earthworms, which can recycle dead organic matter -- thus, reducing waste and enriching the soil.

With human excrement used as fertilizer, the earthworms could allow for a closed and sustainable agricultural system to be established on Mars.

In the latest experiment, scientists sourced soil from a volcano in Hawaii. The soil, which is Mars-like in its consistency and mineral makeup, was able to sprout rocket, or arugula. Researchers used pig feces to fertilizer the plants. After adding the organic fertilizer, the scientists added earthworms.

"Clearly the manure stimulated growth, especially in the Mars soil simulant, and we saw that the worms were active," researcher Wieger Wamelink said in a news release. "However, the best surprise came at the end of the experiment when we found two young worms in the Mars soil simulant."

In the soil, earthworms break down dead plant material. The tiny bits of organic matter they excrete is broken down further by bacteria in the soil, supplying the dirt with nitrogen, phosphorous and potassium, which boosts plant health.

In previous Martian plant growing experiments, scientists have struggled to get enough water to the roots. Earthworms not only help provide nutrients, but also aerate the soil, allowing water to permeate the soil.

The research was part of the ongoing Food for Mars and Moon effort organized by NASA. Related experiments have shown Martian and lunar soil simulants can successfully and safely grow a variety of crops, including green beans, peas, radishes, tomatoes, potatoes, watercress and carrots.