A new study shows that soil bacteria are just as strong against human urine as they are against synthetic fertilizers. This suggests that using urine as fertilizer for crops could be a good idea.
The scientists found that even when large amounts of stored urine were used, it had little effect on the soil bacteria and caused only small changes in soil pH and salinity.
However, they noted that using urine increased certain bacteria that change nitrogen, which could lead to more nitrogen oxides being released compared to synthetic fertilizers.
Co-author Manon Rumeau, from the University of Birmingham, commented: “Our research highlights the potential of recycling human urine to enhance agricultural sustainability, reduce wastewater pollution, and decrease reliance on synthetic fertilizers. Stored urine can be safely applied to a plant-soil system without negatively impacting the soil microbiome.”
Fresh urine is 95% water and contains 5% nutrients like urea, organic compounds, and inorganic salts, making it useful for plant growth.
There has been growing interest in using human urine as fertilizer, but more research is needed to understand its effects on soil and microbes.
In the study, scientists fertilized a spinach crop with two different amounts of stored human urine and compared it to synthetic fertilizer and water in four greenhouse soil tanks.
After 12 months of storage, the urine had fewer bacteria but still contained some common strains. The storage process raised its pH to about 9, which helps kill most harmful bacteria and break down DNA. The soil bacteria were mostly resistant to the urine, with only 3% of the groups affected, and the high salt levels in urine had little impact on the bacterial community.
Journal Reference:
- Manon Rumeau, Chiara Pistocchi, Nassim Ait-Mouheb, Claire Marsden, Brigitte Brunel. Unveiling the impact of human urine fertilization on soil bacterial communities: A path toward sustainable fertilization. Applied Soil Ecology, 2024; 201: 105471 DOI: 10.1016/j.apsoil.2024.105471
