Turns out festival toilet urine is perfect for irrigating crops on Mars

Researchers from Wageningen University It has shown that urine, in the form of the mineral struvite, could be used as fertilizer to grow crops on Mars and the Moon.

Although it may be some time before the first humans set foot on Mars, researchers are already busy speculating about whether we could live on this and other planets. There are more obstacles to this than lack of oxygen. The planet is on average about 220 million kilometers away from us, so a one-way ticket would easily take six months. If we actually visited the planet for a longer period of time, we would have to take a lot of supplies with us. Unless we can grow food on site.

And that's exactly what the research team said Wageningen University In cooperation with her Base project Research in, through their project “Food of Mars and the Moon”. The team is investigating how crops could be grown on Mars and the Moon, using the resources available there: regolith (a loose material that is often weathered on the surface of the planet or the Moon) and ice. Because true Martian and lunar regolith on Earth are respectively unavailable and rare, researchers have used simulators that mimic the composition and texture of these materials to explore how best to grow crops on them.

Core project: Moon/Mars dome as a testing ground
The recently initiated BASE project is focused on building a lunar/Martian dome that contains all the necessities to grow crops indoors. This dome serves as a research facility to test innovations and collaborate in a circular system. The scheme of this can be applied to Mars or the Moon, but also to Earth, for example in deserts or in Antarctica.

muck
This represents a huge challenge. The soil of Mars and the Moon is not known to be very fertile. Regolith naturally contains traces of ammonium, nitrates, phosphates and other essential plant nutrients. In order to grow crops there, the underlying soil must be improved. Researchers say a sustainable, closed-loop agricultural system is crucial. In the past, the research team has succeeded in growing different crops on simulated soil. Including potatoes, carrots, peas, tomatoes, arugula and radishes. But this was not a circular process and therefore would not be sustainable in the long term. This project therefore wants to focus on making food production fully circular, including pollination by insects and the use of bacteria, fungi and worms.

Struvite as a fertilizer
Surprisingly, this process also involves urine. “It comes from portable toilets at festivals in Amsterdam,” says lead researcher Wijer Wamelink. The beneficial substances extracted from this urine were used in this research to grow green beans on fake Martian and lunar soil. Successfully. The only problem is that regolith (and therefore simulated materials as well) can contain traces of toxic minerals that can end up in plants. Therefore, the researchers have not yet eaten cultivated green beans. Struvite fertilizer (a pure mineral that can be extracted from urine and consists mainly of magnesium, ammonium and phosphate) has not yet been officially permitted as a fertilizer for food crops.

But this may be about to change. “With this research we have shown that struvite can be an excellent fertilizer,” Wamelink says. “By using struvite from urine, we can close one of the loops in the golden circle of crop production.” Not only on Mars and the Moon, but also here on Earth, Wamelink emphasizes. “In this way we can reuse human urine in a safe and effective way. This stimulates plant growth and can greatly increase productivity.”