Delivering fertilizer to future Martian colonies is troublesome. It would be much more convenient if the colonists were able to grow crops using available means. A multi-year study, new results indicate that fertilizer from human urine is perfect for this purpose.
Back in 2016, scientists from the Dutch University of Wageningen tried to grow plants in soil as close as possible to the lunar and Martian soil. It was then discovered that the plants did not take root very well in clean soil, but they did much better with the addition of fertilizer from freshly cut grass.
Unfortunately, Mars cannot boast of an abundance of lawns - and growing grass in greenhouses would require a lot of water and free space, which will be in short supply anyway. With this in mind, researchers turned their attention to struvite, a phosphate mineral that was obtained from human urine in sewage treatment plants.
In a greenhouse trial, they planted bean seeds in 60 pots, which they filled with simulated lunar or Martian soil, as well as ordinary earth soil. Half of the pots contained 15 grams of struvite, while the others were left without fertilizer. All plants were watered every day, while the greenhouse was maintained at 20 ° C during the day and 18 ° C at night.
As the legumes sprout, scientists constantly measured their length. It was noted that struvite fertilized plants showed the strongest growth, and by a rather large margin.
As a result, even the plants in the "Martian" soil fertilized with struvite yielded beans, although they did so a week later than the rest. Scientists note that their growth rate could be significantly higher if fertilizers obtained from human feces were also used.