How horse poo could hold the key to life on Mars

Horse poo could hold the answer to life on Mars, according to new research.

Scientists tested horse and pig manure mixed with simulated Martian and lunar soil to see how well lettuces would grow.

The study, carried out by scientists from the Italian universities of Naples Federico II and Basilicata, was published in the peer-reviewed journal Plants on 2 December. It is part of research into the feasibility of feeding astronauts on crewed missions to the Moon or Mars.

The horse and pig manure mix, designed as a substitute for “crew excreta” (the polite term for astronaut poo) and crop residues, was mixed with the Martian and lunar “soil” to see if food production could, theoretically, be possible. For those H&H readers who have watched the 2015 blockbuster The Martian, which tells the story of astronaut Mark Watney’s (Matt Damon) struggle to survive on Mars, this will perhaps sound a little familiar.

The researchers measured lettuce growth, nutrient uptake and nutrient bioavailability in the manure/simulated soil mixes after plant growth.

The simulated Martian soil performed better agronomically – in layman’s terms, Mars grew better lettuces.

But the researchers also found that the simulated soil from both Mars and the Moon “were able to sustain plant growth even in absence of fertilisation”, although the addition of the manure mix did yield better results.

They found that the best crop growth response was achieved with a ratio of 70:30 of “soil” to manure mixture.

There’s still a way to go yet before we see the man in the Moon tending his veg patch. The researchers highlighted that to assess the feasibility of the soil mixes for plant growth in space, these findings need to be validated in follow-up experiments under microgravity.

Something to ponder next time you’re forking the muckheap…

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