When a Tanzanian high school student learned that hair from his school’s salon was nitrogen rich, he had the perfect ingredient to create fertilizer for his country’s farmers.
For most people, a visit to a barbershop or salon to get a haircut is just that. But for David Denis Hariohay, a young scientist from Tanzania, the natural hair that falls to the floor as waste is a valuable raw material that can be converted into nitrogen-rich fertilizer for leafy plants. Hariohay, the co-founder of Cutoff Recycle, an environmental startup, visits Arusha City’s bustling salons and barbershops to solicit natural, discarded hair from bemused barbers. Then, he processes that hair — which otherwise would end up in dumps or landfills — into a low-cost, nitrogen-rich foliar fertilizer (fertilizer sprayed onto plants’ leaves), which he sells to local farmers to nourish their crops.
As a high school student, Hariohay relished high school science competitions. In 2017, he began to wonder if hair from the school’s salon might be of any use. “I was a physics, chemistry, and biology student,” he says, “so I decided to utilize what we are taught in class to research human hair uses.” He and some classmates did some research, learning that plant growth requires nutrients like nitrogen, phosphorus, and potassium. They also found a research paper from India that outlined potential uses of human hair as a fertilizer.
With guidance from his science teachers, Hariohay conducted laboratory tests revealing that hair contained amino acids like nitrogen; indeed, nitrogen makes up seventeen percent of human hair — one of the highest levels among organic materials. Applied to the soil in its raw form, hair releases the nitrogen slowly. Its sluggish decomposition is due to keratin protein, which can take up to two years to fully decompose. Hariohay solved this problem by mixing hair with potassium hydroxide pellets to break down the keratin, creating a liquid fertilizer that would enable a faster release of nutrients to growing crops.
Farmers use Cutoff Recycle foliar fertilizer on tomatoes, maize, spinach, carrots, and cabbages, as well as in flower gardens. The fertilizer can be applied to the soil using a drip irrigation kit, or sprayed directly onto the leaves of growing crops. About two teaspoons mixed into four cups of water will fertilize an acre of land.
Kennedy Richard Mafie, who grows maize and carrots on his farm in Songoro, Arusha, has seen the benefits of using Cutoff’s fertilizer. “My initial motivation to try [it] was because it’s organic and chemicals-free,” he says. But after applying it, he was sold: he harvested four additional bags of maize and five more bags of carrots than in previous years, and he noticed a reduction in insect and other pest problems. He is certain that farmers who witness others’ higher yields after using the fertilizer will want to use it, too.
The five member staff at Cutoff Recycle pays roughly one hundred young people and barbers to collect about 130 pounds of hair monthly. The natural hair is sorted to remove impurities and cleaned with acetone to remove microorganisms and gels. According to Hariohay, fifty grams (less than two ounces) of hair makes about four cups of the foliar fertilizer.
Cutoff Recycle currently has eight farmers as regular customers, for whom, depending upon their orders, it produces about fifty-three gallons of the foliar fertilizer monthly.
Fertilizer application in Sub Saharan Africa (SSA) is among the lowest in the world. While experts believe that optimal crop yields require an annual forty to fifty kilograms of fertilizer per hectare (88–110 pounds for every two and a half acres), actual annual fertilizer usage per hectare in SSA is estimated to be only about eight kilograms, which is among the reasons that the continent grapples with chronic food insecurity. In SSA, nitrogen makes up ninety percent of all applied fertilizer, thereby making it a vital crop nutrient for addressing food insecurity. Crops that lack nitrogen grow slowly and poorly (with yellowing leaves), which results in low yields.
The 2006 Abuja Declaration on fertilizer recommended the need to increase nitrogen application per hectare to fifty kilograms (about 110 pounds) by 2015, with the goal of improving soil fertility so that African farmers can be food secure and improve their economic livelihoods. But in Tanzania, more than ninety percent of the fertilizer used is imported, which often makes it prohibitively costly for small scale farmers.
“So we [Cutoff Recycle] aim to provide our organic fertilizer at the cheapest price we can, and at the best possible quality,” Hariohay says. A liter of Cutoff Recycle’s foliar fertilizer costs $2 (TShs5010), which, according to Hariohay, is sixty percent cheaper than conventional fertilizers in Tanzania. He adds, “Demand (here) is high.”