Modern synthetic fertilizer consists of varying amounts of nitrogen (N), phosphorus (P) and potassium (K), which are added to croplands to replace these depleted nutrients in the soil. There are several problems with this method, one of the primary ones being that these are finite resources.
Nitrogen, for instance, must be captured through a process that requires natural gas. And, unlike nitrogen, phosphorus and potassium cannot be synthesized, and our aggressive large-scale farming methods, which deplete soils of nutrients that then must be replaced, are quickly burning through available phosphorus and potassium stores.
We’re now hearing discussions of “peak phosphorus and potassium” in the way we discuss “peak oil,” and, according to some, we may soon be facing looming shortages of these two critical fertilizer ingredients. According to well-known investor Jeremy Grantham, writing for Nature:
“These two elements cannot be made, cannot be substituted, are necessary to grow all life forms, and are mined and depleted. It’s a scary set of statements. Former Soviet states and Canada have more than 70 percent of the potash [potassium]. Morocco has 85 percent of all high-grade phosphates [phosphorous]. It is the most important quasi-monopoly in economic history. What happens when these fertilizers run out is a question I can’t get satisfactorily answered and, believe me, I have tried. There seems to be only one conclusion: their use must be drastically reduced in the next 20-40 years or we will begin to starve.”
Urine May Represent the Future of Fertilizer
Human urine is naturally rich in nitrogen, potassium, and phosphorus, and with about 30 billion gallons produced every year in the US alone, it’s certainly in abundant supply. For the average person, a year’s worth of urine contains about eight pounds of nitrogen and nearly one pound of phosphorus – that’s enough to grow about one year’s worth of food!
I am in complete agreement with this concept and for the last year have been collecting all my urine and putting it in the that I feed my fruit trees, vegetables, herbs, and aloe. It works wonderfully with , as the nitrogen in the urine helps balance the carbon in the biochar.
According to the Rich Earth Institute, which is running an experiment in nutrient reclamation, using source-separated urine as a fertilizer, getting urine out of wastewater and into agriculture will not only help reduce pollution but also represents a viable natural fertilizer for the future. They state:
“The average person flushes the toilet five times a day, and four of those times are just for urine. This means that 80% of our flushwater-or over 4,000 gallons of clean water each year per person-is used just to get rid of urine! That is a lot of clean water used to transport ‘liquid gold’ into the sewer, where it becomes pollution. If we save it instead of flushing it, we can harvest a valuable resource that we can use in agriculture.“
The Rich Earth Institute experiment is the first legally authorized community-scale “urine reuse” project in the US, but field trials involving urine fertilizer are already underway in many other countries, including Europe, Africa, and Asia.
As for the “yuck factor,” human urine isn’t nearly as “gross” as it seems, since it’s virtually sterile when it leaves your body. Just to be sure (since urine can become contaminated by fecal particles), the Rich Earth Institute “pasteurizes” collected urine in solar heaters prior to sprinkling it on crops. The first experiment, conducted in 2012 on a hayfield, yielded impressive results…
-Urine-treated hay was darker green in color and more lush than control plots
-Hay treated with the most urine (100 pounds of nitrogen/acre) yielded 5.8 times as much hay as the control plot
-Hay treated with the mid-level amount of urine (50 pounds of nitrogen/acre) yielded 3.8 times as much hay as the control plot
In 2013, the field trial was expanded, both in the number of volunteers donating urine and the scope of the field trials. The group began testing for optimal dilution rates of urine when applied to hay and they’re now working with the US Environmental Protection Agency (EPA) testing the use of urine fertilizer on vegetables.
The idea seems to be catching on quickly, as they now have three additional farms using urine fertilizer, along with a waiting list that’s only hindered by how much urine they can collect. Ultimately, they’re hoping to create “peecycling” programs that other cities and states can copy, but this will require some major changes to regional and national policy and wastewater treatment facilities.
Urine Plus Ash Makes Beets Grow Nearly 30 Percent Larger Than Conventional Fertilizer
Separate studies have also shown promise in using urine as fertilizer. In one experiment, researchers compared beets grown in four different ways: one with conventional mineral fertilizer, another with urine, a third with urine and wood ash, and a final control group grown with no fertilizer.
The beets fertilized with urine were 10 percent larger, and those fertilized with urine/ash were 27 percent larger than those grown in mineral fertilizer. As for nutrient content, all the beets were similar, and in a blind taste test the beets were rated as equally flavorful.
The researchers concluded that urine is a perfectly viable source of fertilizer, and one that is readily available and sustainable (the average American urinates 500 liters a year). Urine has also been used to fertilize cabbage, tomatoes, sweet peppers, and cucumbers, with similar favorable results, and it’s free – unlike synthetic fertilizers that some farmers around the world can scarcely afford.
Setbacks to Widespread Use of Urine Fertilizer
There are some issues that must be overcome before urine fertilizer can become “mainstream.” Although urine is technically sterile, it does contain traces of pharmaceuticals, which are not removed at wastewater treatment plants. The Rich Earth Institute is currently working with the EPA to track how the soil is absorbing these types of contaminants from urine fertilizer.
“When we use flush toilets that are connected to sewers, these residual drugs pass largely unchanged through the treatment plant in about twenty-four hours and then go directly into rivers, lakes, or the ocean, where they can harm sensitive aquatic life and end up in our drinking water. If we spread the urine on agricultural land instead, the robust soil ecosystem has a chance to break down the drugs and biodegrade them over a much longer period of time, greatly reducing or eliminating their levels before they ever reach a body of water. In this way, soil application is a great improvement over current practice.”
So far, research suggests that any residual hormones or pharmaceuticals are likely to be negligible and basically non-existent in urine-fertilized crops. In fact, there may be benefits to spreading such urine contaminants on land, as opposed to depositing them in waterways, as is currently done. The Rich Earth Institute explained:
“Using specially designed toilets that collect urine separately from feces, urine can be collected in a storage tank instead of being flushed down the drain. After being sanitized, it can be used as a high-nitrogen liquid fertilizer, taking the place of chemical fertilizers. This system is more efficient than sewer-based sanitation at getting all the nutrients from the urine to the farm, because the source-separated urine is directly collected and transported. In municipal wastewater, the nutrients in the urine are incredibly dilute, and so it is very challenging to extract them again. In fact, many treatment plants let most of the nitrogen and phosphorus pass through untreated. Some do capture the phosphorus, but most which treat for nitrogen drive it off as a gas, rather than capturing it as fertilizer.”
Another issue is the fact that sewage systems would have to be radically redesigned to separate liquid waste from solid, a practice that requires the use of separating toilets that have a divided bowl and independent pipes to keep the urine separate. There are other benefits to using separating toilets as well, such as less water usage and less energy requirements in sewage treatment. However, neither the toilets, nor the sewage systems, are in widespread use in the US. As reported by the Rich Earth Institute:
However there is nothing that is preventing you and your family from implementing this system now. If you have a garden, it is relatively easy to collect your urine and apply it to the garden. This will present less of a burden on your water filtration facility, but, more importantly, it puts the nutrients where they belong, back in the soil, not in the water system. It is easy to collect the urine in one-quart wide mouth Ball jars and then transfer them to larger 2.5-gallon containers if you need to. Just be careful to dilute it about 5:1 before you apply it to the soil that surrounds the plants you want to nourish.
Biological Agriculture Is the Future of Food
The use of urine as fertilizer is a major improvement over chemical fertilizers. However, according to , an internationally recognized expert on the benefits of sustainable soil science, the real nutrition your plants require is actually derived from microorganisms in the soil. These organisms take the mineral material that’s in your soil and convert it into a plant-available form. Without these bioorganisms, your plants cannot get the nutrients they need. So what you need is not more soil additives; what you need is the proper balance of beneficial soil organisms.
According to Dr. Ingham, there’s no soil on Earth that lacks the nutrients to grow a plant. She believes the concept that your soil is deficient and needs added phosphorus or nitrogen in order to grow plants is seriously flawed, and largely orchestrated by the chemical companies, because it’s based on looking at the soluble, inorganic nutrients that are partly present in your soil.
Interestingly enough, you can use a starter culture to boost the fermentation and generation of beneficial bacteria much in the same way you can boost the probiotics in your . For compost, this strategy is used if you want to compost very rapidly. In that case, you can use a starter to inoculate the specific sets of organisms that you need to encourage in that compost. This is but one example of high-performance agriculture methods, which are a FAR superior alternative to attempts at “improving” agriculture through the use of genetic engineering and chemical fertilizers. In order for plants to flourish, the soil must first be made hospitable for beneficial microorganisms. To accomplish this, you need to:
1. Have the right nutrient balance in the soil
2. Inoculate the soil. This can be done by adding soil probiotics or basic fermentation products such as compost tea
3. Apply proper food (fertilizer) for the microorganisms to consume and thrive. The microbes in turn will then feed the proper nutrients to the plants grown in that soil. The better you’re able to fertilize the microbes, the healthier your plants will be, and the fewer plant diseases, pest infestations and weed problems you’ll have
Biological Gardening/Farming Aims to Bring Health Back to Soil
Urine fertilizer may have an important place in high-performance agriculture, but there are other exciting advancements as well, including things like humic acid or humates, which promote the proliferation of beneficial microorganisms in the soil, as well as sequester carbon in the soil.
The application of (charcoal created by slowly heating biomass such as wood and plant materials in a low-oxygen environment) to soil may also help sequester carbon for hundreds, perhaps even thousands of years, and radically improve soil fertility by serving as a substrate for beneficial soil microbes. Biochar works particularly well with urine as it captures the nitrogen like a magnet and releases it slowly to the microbial community that will feed the plants. Otherwise, the nitrogen can easily leach away.
are also creating a natural product known as “vermicompost,” which greatly improves plant growth and make plants more resistant to disease and insects than plants grown with other composts and fertilizers. Personally, one of my new passions is sustainable, , and Dr. Arden Andersen is a world leader in this field
It’s important to realize that modern industrial agriculture has veered quite far from the basic sciences of soil cultivation and plant nutrition. According to Dr. Andersen, the reason they’ve been able to make such great strides in increasing the nutritional density and yield of their crops is by returning to those basic sciences using synthetic fertilizers, etc. But this is better done naturally. For more information, including how to try biological agriculture in your own backyard, watch my interview with Dr. Andersen below.
If you want to use urine to fertilize your backyard garden, feel free. But keep in mind that urine should be diluted with water for most plants and should be separated from solid waste to avoid contamination (so collect your urine in a bottle or bucket, or invest in a urine-separating toilet). You can also add urine to your compost heap to enhance its nutritional content, or like I do, add it to your that you add to nourish your plants.
Grist March 12, 2014
Gizmodo January 14, 2014
Nature November 14, 2012
Rich Earth Institute, The Solution
Rich Earth Institute, FAQs
Rich Earth Institute, FAQs
Journal of Agricultural and Food Chemistry February 10, 2010
Yahoo Voices April 24, 2013
Rich Earth Institute, FAQs
Rich Earth Institute, The Solution