VIDEO. In Saclay, farmers use human urine as fertilizer for growing wheat

"Go pee on the rhubarb!"

".

This grandmother's advice seems to inspire many researchers and NGOs who are working on an alternative to chemical fertilizers, which are not very respectful of the environment.

Their idea?

Using an unexpected and natural ingredient for crop spreading: human urine.

Agronomy researchers from the Chamber of Agriculture are currently conducting this experiment on wheat plots in Saclay, Essonne.

This Monday, April 25, Lucie Baron, in charge of the project, is transporting cans filled with urine to an agricultural machine.

Inside, the famous chestnut liquid of human origin freshly harvested during a music festival.

“We are filling the tank of the spreader.

This spreader will allow us to then apply the urine all over the place,” she explains.

At the controls of his machine, Emmanuel Laureau, a farmer, runs and sprays the liquid on his wheat shoots.

For him, human urine has all the nitrogen and nutrients needed to feed his land.

“Of course we can use human urine, instead of it being lost in sewage treatment plants.

Because today, that's what's happening, it's vanishing and it's lost in the atmosphere.

So we might as well reuse it on our crops”.

Read alsoIn Paris, your urine is used as fertilizer for farmers

To grow, “plants need nutrients, nitrogen, phosphorus and potassium, explains Fabien Esculier, engineer and coordinator of the OCAPI research program in France.

When we eat, we ingest these nutrients before excreting them, mostly through urine.”

Moreover, for a long time, urban excrement was used in agricultural fields, before being supplanted by chemical fertilizers, which certainly offer a better yield, but which, when used in excess, pollute the environment.

Not to mention their prices which continue to soar, even more so with the war in Ukraine.

"Two years ago, we already had this same type of experiment and we had plots that were fertilized in part with human urine which had given us satisfactory results compared to a conventional fertilizer", analyzes for its part Christophe Dion, head of the agronomy department at the Chamber of Agriculture of the Ile-de-France region.

The yield of the urine-dried crops was even almost equivalent, with “good quality” of the grains.

Problem: How do you catch more human urine in urban areas where the majority of standard toilets are flushed before sending it all down the drain?

To collect urine at the source, we would have to rethink our toilets, the collection network... But also go beyond our a priori on the famous dry toilets, considered impractical and unsightly.

Not to mention the bad smells.

"There are indeed obstacles to overcome", comments Marine Legrand, anthropologist and member of the Ocapi network.

But "we are beginning to understand how precious drinking water is" and "it becomes inadmissible to still defecate in it", she continues.

Would people still be ready to eat foods fertilized with urine?

A study shows marked differences between countries.

The acceptance rate is very high in China, France or Uganda, but low in Portugal or Jordan.