Urine that has sat in the sun for a while seems to fertilise crops while warding off pests, without affecting the produce’s taste
By Matthew Sparkes
1 April 2025
People harvesting cowpeas in Tahoua, Niger
Jake Lyell/Alamy
Human urine that has been matured in the sun for at least one month appears to be both a fertiliser and an effective pesticide. The findings could be particularly helpful for combatting insect infestations in West Africa, where soil quality is typically low and traditional pesticides are expensive.
Farmers taking part in a previous trial in Niger to investigate the use of urine as a fertiliser discovered that it was also having a pesticide effect, as plants treated with it had less pest damage than those that weren’t.
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Laouali Amadou at the National Institute of Agricultural Research in Niger and his colleagues decided to test the findings on cowpeas , a vital crop in the country because of its drought tolerance.
Experiments were carried out in several villages across Niger to compare the effects of chemical pesticides and human urine on the crop’s pest resistance. Three applications were made at each site, with a week between treatments.
The team found that plots treated with synthetic pesticides had the lowest insect damage. But those treated with human urine had 20.5 times less infestation than control areas and their crop yields were 1.8 times higher.