Urine contains many nutrients that are beneficial for plant growth, such as nitrogen, phosphorus, and potassium. Many cultures around the world have used urine for centuries as a fertilizer. Given the skyrocketing pricing for synthetic fertilizers like urea, is it time to give some real consideration to this idea?
Urine is 95 percent water. Dissolved in that water are trace amounts of vitamins and minerals which are necessary to plant health and growth, but the important part is that remaining 5 percent: it is largely composed of a metabolic waste product called urea, and urea is why urine in agriculture can be a very good idea.
What is urea? Urea is an organic chemical compound produced when the liver breaks down proteins and ammonia. Half the urea in your body remains in your bloodstream while the other half is mostly excreted through the kidneys as urine. A smaller amount is excreted through sweat.
Urea is also the largest component of modern commercial fertilizers. It contains large amounts of nitrogen, which is essential for healthy plant growth. Urea has nearly replaced ammonium nitrate as a fertilizer in large farming operations. Although this urea is artificially produced, its composition is the same as that produced by the body. Manufactured urea fertilizer can, therefore, be considered an organic fertilizer. When applied to the soil, both will convert to the ammonia and nitrogen needed by plants. There is one difference between natural and artificial urea – fertilizer produced in the lab will have a more consistent concentration, giving the farmer a little more precise control over the input.
With the invention of sewage systems, urine was no longer available for other uses like softening leathers or bleaching clothes. Is there a way to restructure modern sewage systems to capture urine? It’s not a frivolous thought, as scientists claim that urine diversion would have huge environmental and public-health benefits if introduced on a large scale around the world.
Urine diversion is estimated to have a significant positive impact on our planet:
- reduction in greenhouse-gas emissions by up to 47%
- reduction in energy consumption by up to 41%
- reduction nutrient pollution from the wastewater by up to 64%
- contribution to a freshwater saving of up to half of the volume used.
According to estimates, the human population produces enough urine to replace about a quarter of current nitrogen and phosphorus fertilizers worldwide.
In 2014, the city of Amsterdam launched a campaign to raise awareness of a phosphorus shortage by setting up public urinals and educating the public on repurposing pee as a plant fertilizer. There are many places around the globe where the use of chemical fertilizers is cost-prohibitive. Creating the opportunity or necessity to take advantage of recycled nutrients by transforming what was waste into a viable resource provides more farmers with the inputs to increase yields and mitigate the challenges of global food insecurity.
