Earth Worms Thrive and Reproduce in Martian Soil Simulant

‘The positive effect of adding manure was not unexpected’, added Wamelink, ‘but we were surprised that it makes Mars soil simulant outperform Earth silver sand’. Researchers added organic matter from earlier experiments to both sands. They added the manure to a sample of the pots and then, after germination of the rucola, they added the worms. The result: pots with all possible combinations with the exception of organic matter which was added to all of the pots.

Wieger Wamelink

Credit: Wageningen University

Worms are very important for a healthy soil, not only on Earth but also in future indoor gardens on Mars or the moon. They thrive on dead organic matter such as old plant remains, which they eat, chew and mix with soil before they excrete it. This poo still contains organic matter that is broken down further by bacteria, thus releasing nutrients such as nitrogen, phosphorous and potassium for use by the plants. By digging burrows the worms also aerate and improve the structure of the soil, making watering the plants more effective.

The latter proved to be very important in earlier experiments where water would not easily penetrate the soil. Wamelink confirmed that: ’the application of worms will solve this problem’.

To feed the future humans living on Mars or the moon the project Food for Mars and Moon aims to set up a sustainable agricultural system. It is based on the presence of soils and water (in the form of ice) on both Mars and the moon, and for the Earth-based research we are using soil simulants delivered by NASA. The simulants originate from a volcano in Hawaii (Mars) and a desert in Arizona (moon).

The experiments started in 2013. Nowadays we are able to grow over a dozen crops, the only species that has resisted our efforts so far is spinach. However crops such as green beans, peas, radish, tomato, potato, rucola, carrot and garden cress all seem possible. The crops were analysed for heavy metals and also alkaloids to check their safety for human consumption. After passing these tests researchers organized a dinner based on the harvested crops for the people that supported their research via the crowdfunding campaign.