By Ben
Coxworth
Bean plants
grown without the urine-based fertilizer grew no taller than 25 cm (9.8 in)
Wageningen University
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It was back
in 2016 that we first heard how scientists at The Netherlands' Wageningen
University were trying to grow food plants in simulations of both lunar and
Martian soil. At the time, it was found that while the plants didn't fare well
in nothing but the soil, they did better when a fertilizer made of fresh-cut
grass was added.
Unfortunately, though, the Red
Planet isn't known for its lush lawns – and growing grass in Martian greenhouses
would use up a lot of water and space. With that in mind, the researchers more
recently looked to struvite – it's a phosphate mineral, which they obtained from
human urine in wastewater treatment facilities.
In greenhouse tests, they planted
string bean seeds in a total of 60 pots that were
filled with either simulated lunar or Martian soil, or with regular
Earth-type potting soil. Half of the pots additionally
contained 15 grams of struvite, while the others had no added fertilizer. All of
the plants were automatically watered daily, with the greenhouse being kept at a
temperature of 20º C (68º F) at day and 18º C (64º F) at night.
On days without sufficient
daylight, grow lamps were switched on Wageningen University
As the bean plants sprouted,
their length was monitored. The scientists noted that all of the struvite-fertilized
plants showed the strongest growth, by quite a wide margin – particularly those
grown in the lunar and potting soils.
The Martian-soil struvite
plants did ultimately produce harvestable beans,
although they did so a week later than the other two. That said, their growth
rate might be boosted substantially if fertilizer obtained from human feces was
also used.
Source: New Atlas URL:
https://newatlas.com/science/human-urine-mars-plant-fertilizer/Wageningen
University