Chickpeas sprouted on Moon soil, thanks to fungi

Extraterrestrial agriculture is the key to food sustainability in a quest for space exploration. In a recent push, researchers have successfully cultivated chickpeas in the Moon’s soil.

Two researchers, Jessica A. Atkin from Texas A&M University and Sara Oliveira Santos from Brown University, have tackled the issue of food security in space by finding a way to grow crops in the harsh lunar environment.

“Food sustainability is one of the most significant barriers to long-term space travel. Providing resources from Earth is not cost-efficient, and resupply missions are not viable to meet the needs of long-term life in deep space conditions,” scientists wrote in their research paper.

The Moon soil, also known as regolith, is a compound of dust, glass beads, and fragments of rocks. Similar soils covering solid rock can be found on Earth, Mars, some asteroids, and other planets and moons in our solar system.

Lunar regolith as a planting material is challenging because it contains toxic hard metals, radiation contamination, no organic matter, and lacks essential microorganisms. Additionally, it doesn't hold water well, has limited nutrients, and doesn't support the necessary microbiome for efficient nutrient conversion and plant growth.

Previous experiments using lunar regolith samples returned from the Apollo missions showed that seeds could sprout successfully in the short term when exposed to irradiated lunar samples. However, the plants grew more slowly, and prolonged exposure to heavy metals in the soil led to toxicity in their leaves and stalks.

Fungi to reduce toxicity

Researchers used a lunar regolith simulant to create a growth medium for crops. They chose to cultivate chickpeas, a plant that’s used globally as a nutritious protein substitute for meat and has been used widely in studies evaluating the remediation of radioactive and metal-contaminated soils.

To solve the problem of toxicity and enhance the soil’s properties, they added Arbuscular Mycorrhizal Fungi (AMF) and compost made by worms – Vermicompost (VC).

AMF is known for helping to clean soils contaminated with heavy metals. They also improve the cycling of nutrients in the soil and produce a substance called glomalin, which acts like a glue to hold the soil particles together and make it more resistant to erosion.

Vermicomposting is a process where red wiggler earthworms, along with microorganisms, break down biowaste to create a nutrient-rich soil conditioner. The end product contains essential nutrients and minerals for plants and has a diverse mix of microorganisms.

The earthworms contribute by producing soluble nutrients and humus, which enhances soil quality by promoting aggregate formation, reducing soil density, modifying structure, and improving water retention.

The experiment took place for 120 days. On day 16, all seeds had germinated. The results of the research showed that the fungi and VC extended the survival of plants on lunar soil by two weeks on average. Scientists believe that their study is the first step in understanding how to make plants grow well on the Moon.

“Our results show that regeneration methods used on Earth soils can help condition lunar regoliths,” the researchers concluded.