As the Russia-Ukraine war and climate change pushup fertiliser prices, coupled with circulation of substandard fertilisers  across the country, adoption of human poo as fertilisers has begun to gain traction. Scientists say human poo is rich in phosphorus and potassium, which are important nutrients for boosting crop yields, restoring soil health, and reducing dependency on expensive chemical inputs. GBENGA AKINFENWA writes that the adoption has, however, sparked a serious debate among researchers who claim it portends a high health risk.

At the beginning of rainy season, last year, the retail price of NPK 20:10:10 fertiliser was N49,000; NPK 15:15:15 – N52,000; Urea was N36,500; granulated diammonium phosphate (DAP) was N70,000 per 50kg bag, while single super phosphate (SSP) was N39,500.

Despite outcry of farmers on high cost of the commodity, in July, the prices further went up sharply, with DAP rising to N96, 000, NPK 20:10:10 to N60, 000, and NPK 15:15:15 reaching N108, 000 depending on the location. Currently, Urea is N41,000, NPK – N45,000 and other brands N50,000 upward.

Sadly, this development has led to circulation of counterfeit fertilisers across the country, a development, experts say, has severe implications on crop production and consumption, farmers’ livelihood, environment and human health.

According to them, the rising menace of these counterfeit or substandard fertilisers usage is responsible for poor crop growth and reduced yields. It also causes reduction of soil fertility and makes crops more susceptible to diseases, thereby, putting the country’s food security dream at risk.

Experts say the cost of fertiliser along with climate change would have the biggest impact on food security and could cause up to one million more people to die from malnutrition.

A farmer at the Lagos State University (LASU), Ojo, LASU Gate Farm, Ibrahim Usman, who lamented how these fertilisers have been failing to nourish crops, said many of them often cause plants to burn and become unsellable.

He noted that while purchasing these fertilisers in small quantities from dealers owing to limited funds, the farmers often unknowingly buy substandard products that lead to significant losses.

Another farmer, Omotayo Omoniyi, who also lamented this development, said the issue is having a devastating effect on plant health and farmers’ finances.

A study by researchers at Edinburgh University warned that soaring farming costs, mostly driven by high fertiliser prices, could leave an extra 100 million people starving around the world.

Investigations show that these twin challenges – the high cost and circulation of fake fertilisers – is driving farmers to alternative, which is application of human manure to boost their yields, enhance their productivity and also increase their incomes.
However, while many Nigerians are not familiar with animal manure – packed with nitrogen, phosphorus and potassium – biosolids are becoming a common place among farmers across the country.

Some farmers are adopting its use as a potential fertiliser for agricultural use. This, according to them, is because they contain similar nutrients to animal manure.

Biosolids are nutrient-rich, organic, semisolid materials derived from treated sewage sludge – the byproduct of municipal wastewater treatment. Through physical, chemical, and biological processes (like digestion and drying), they are stabilised to reduce pathogens, making them safe for beneficial reuse as fertiliser, soil amendment, or land reclamation.

Biosolids can be used as a compost to help fertilise soil so that crops can grow. Biosolids in the soil provide nutrients and organic materials for the crops and plants to absorb, such as nitrates and phosphates.

Human waste is recovered from water treatment works and the organic material they collect is known as sewage sludge. The waste is searched for harmful materials and the water is removed, leaving only the biosolids. Any sewage sludge that is being sent to be used as biosolids must be tested for heavy metals such as mercury, zinc, and copper.

An unfortunate downside to using biosolids in soil is the smell that comes with it – winds can carry the foul smell into towns, and it can linger for a few days.
Experts claim that human faeces are rich in phosphorus and potassium, which are important plant nutrients, and it also contains carbon, which can increase the fraction of organic matter in soils.

More organic matter in soils is especially important to improve the soil structure in tropical countries so that it becomes more resistant to droughts and to erosion from heavy rains and floods. It is also known that an increase in organic matter through the use of compost can make plants more salt-tolerant.

Investigations showed that the use of human excreta as manure in agriculture is becoming a practice in Nigeria, particularly in areas largely driven by the high cost of synthetic fertilisers.

Some farmers observed that crops grown with human waste perform better than those grown with commercial fertilisers, as it is rich in the essential nutrients.

It was gathered that the practice has historical precedents. The ancient practice of applying human excreta to the land has maintained soil fertility in many countries of Eastern Asia and the Western Pacific for over 4,000 years, and remains the only agricultural use option in areas without sewerage facilities.

Investigations showed that in the past, usage of human faeces to boost crops was a common phenomenon, especially in rural communities, as there were quite a fewer number of toilets or latrines.
At the period, community dwellers relieve themselves in nearby bushes and farmland, just as farmers and their families prefer to defecate on their plantations to serve as manure.

Human excreta are frequently used in some areas of the world such as China, Vietnam and Japan without any generally known problems for agricultural productivity, although its improper use is linked to hygiene and health problems. The practice of reuse has also been common in Europe.

Reports have it that evidence of the emptying of the contents of latrine pits into agricultural fields can still be seen in the soil of the experimental farm of the University of Helsinki.

It is argued that with a better-closed nutrient loop, many more people, including low-income farmers, would be able to produce more food and other plant products. It would also reduce the pollution effects from unsafe excreta disposal and surplus use of chemical fertilisers and protect surface and groundwater and the air.

A more effective utilisation of human excreta, according to experts, would also reduce the waterborne enteric microbiological diseases, since there would be less contaminated wastewater and the die-off of enteric microorganisms could be controlled better.

The Guardian confirmed that while the practice has not been totally eradicated, however, it is currently getting more traction as a result of the increasing cost of fertiliser, which is becoming unaffordable to farmers across the country.
Author Franziska Hafner, a student at the University of Hohenheim in Stuttgart, said products made from human urine and faeces “are viable and safe nitrogen fertilisers” and “did not show any risk regarding transmission of pathogens or pharmaceuticals”.

The work by experts in Germany also looked at modern products already being made from human urine, which are turned into ammonium and nitrate.

This included Aurin, which was recently approved for use in agriculture in Switzerland, Liechtenstein and Austria, and CROP – combined regenerative organic food production – which is part of ongoing space projects to recycle wastewater for future bases on the moon and Mars.
The lead author of the study, Dr. Ariane Krause, a scientist at the Leibniz Institute of Vegetable and Ornamental Crops in Germany, said: “If correctly prepared and quality-controlled, up to 25 per cent of conventional synthetic mineral fertilisers in Germany could be replaced by recycling fertilisers from human urine and faeces.

“Combined with an agricultural transition involving the reduction of livestock farming and plant cultivation for fodder, even less synthetic fertiliser would be necessary, resulting, for example, in lower consumption of fossil natural gas.
“Our study results demonstrate that nitrified urine fertilisers such as Aurin and CROP have a huge potential as fertiliser in agriculture. They argue for a greater use of these recycled products in the future.”

The peer-reviewed research has been published in the journal, Frontiers In Environmental Science, and comes amid record-breaking food inflation, with many shoppers struggling with supermarket bills.
T
he Guardian learnt that the usage of human waste as manure is getting rampant in states, especially Kano State, as farmers lay siege to houses where their septic tanks are being emptied.

A farmer in Dante Quarters of Kumbotso Local Council, Hussain Saeed, said they found it difficult to afford fertiliser, hence, the resort to human composts in preparation for the rainy season farming.

A pastor who resides in Kano metropolis, Edem Bassey, told The Guardian that sourcing human excreta for the purpose of manure is actually a hot cake in Kano, as farmers ‘scamper’ for the waste to outsmart others.

He said: “Human wastes in Kano are now an essential commodity to farmers. Once these farmers see that the septic tanks of houses are being emptied, you immediately see them negotiating with the sewer suction trucks to offload the waste on their farms or designated places for onward movement to their farms.

To them, the waste serves as direct alternatives to fertiliser, which they have been used to over the years.

“Some even go as far as ‘settling’ these drivers as the demand is far outweighing supply. On its own, this is becoming more like a business as young men are seen loitering streets searching for where human wastes are being emptied.”

A recent investigation by The Guardian attested to Bassey’s claim. It was gathered that farmers growing various crops, such as sorghum, maize, millets, carrots and other vegetables are currently sourcing compost manure from human excreta excavated from pits latrines.

One of the local pit latrine evacuators, Idi Musa, revealed that some farmers contacted him to supply human composts to their farms owing to the high prices of fertiliser.

“Initially, we usually pour the wastes in ponds or at refuse dumpsites; but currently, farmers book it to fertilise their crops and we discharge the wastes at a cost per truckload.”

Mr. Tola Aribisala, a cassava farmer based in Ilara, Imeko area of Ogun State, said in the past they relied much on use of human excreta on their farms as this helps in enhancing crop production.

“Farmers who plant pepper, potato, tomato and leafy vegetables often use human faeces on their farms. They do not use chemical fertiliser, as they are scarce and expensive. As at that period when there were fewer toilets, we often defecated on our farms and when it rains, these spread to every part of the farm.

“Though development has taken place and fertilisers are available in nearby shops and markets, we still have some of our people who are still using these faeces to boost their plants. People cannot differentiate crops planted by human excreta and those boosted by fertilisers except when the farmer tells you.  It is an old method and it actually worked in improving soil fertility.

“I can confirm to you that aside from diluted urine of rabbits and animal droppings, human faeces are currently used as fertiliser for planting plantains, cucumbers, watermelons, and corn and this has worked greatly in improving their yields.”

Prof. Nkiru Theresa Meludu of the Department of Agricultural Economics and Extension, Nnamdi Azikiwe University, Awka, Anambra State, in her article published in the Journal of Environmental Extension, said: “There are differences in the yield on the crops grown with fertiliser and human waste. The crops grown with human waste perform better than the ones grown with fertiliser. An alternative approach to avoid the disadvantage of conventional fertiliser is the use of human waste.

“The plant nutrient in both urine and excreta come from arable fields and thus should be recycled as fertilisers to support sustainability and retain fertility of the soil. Urine acts very fast and is very rich in nitrogen.”

A soil fertility expert based in Abeokuta, Ogun State, said if the use of human excreta is embraced, it is capable of reducing the need for synthetic fertilisers, thereby, decreasing greenhouse gas emissions associated with synthetic fertiliser production and lowering the carbon footprint, thus mitigating the effects of climate change.

“Its performance is comparable to that of mineral fertilisers and, in some reports, even superior. Like other organic fertilisers, crops grown with human excreta also demonstrated improved quality in terms of nutrition and shelf life.”

He stated that human faeces could be utilised as a standalone fertiliser or in conjunction with other types of fertilisers, depending on the composition of each batch and the limiting nutrients present in the soil.

However, an agricultural extension specialist/rural sociologists at the Ahmadu Bello University, Zaria, Dr. Yusuf Abdulahhi, said he has no facts to validate the claim that human waste can be used as fertiliser in home gardens, but its dependence on large farms is uneconomical.

“Human waste handling and use as fertiliser will not be cost effective, and health risks are high. There’s neither research data nor field experience to support the claim. Traditionally, animal manure, poultry manure and household waste are commonly used as alternatives to inorganic fertilisers. They’re being used even at present. Generally, organic manures are scarce and they are needed by crops in large quantities. Therefore, obtaining them in adequate amounts is not easy.

“When septic tanks, in homes and public places, are evacuated, using special equipment and vehicles made for the purpose, they may be discharged in farmlands. How many farmers can afford that service? How much human waste manure can our septic tanks supply to agriculture?

“Practically speaking, the supply, the cost, affordability, and know-how to manage human waste make it unattractive as manures; also its viability as an alternative to commercial inorganic fertilisers. Human waste isn’t a viable alternative due to the cost, the availability, the technology involved in its handling, and health implications.”

Yusuf added that human waste is not always readily available in commercial quantities, noting that even countries that have the technology have not ventured into it.

On his part, the Lead Strategist, FutuX Agri-consult Ltd, Olarewaju Babatunde Emmanuel, who confirmed that the practice of using human waste as manure has been on for several years, said he is unsure of its popularity currently.

He said: “It cannot be an alternative to fertiliser because it has a lot of toxic substances from human beings. Many farmers don’t have the required knowledge and skills to convert it to less harmful substances. Those toxins need to be removed totally from the faeces.

“It is not healthy at all and its disadvantages outweigh the advantages. Such practice should not be encouraged among farmers. It is a public health concern. It would definitely have an impact on human health. So many diseases could be transferred easily through human faeces.”

A public health expert, John Eze, said the primary concern with using human excreta is the potential presence of harmful pathogens, including bacteria, viruses, and parasitic worm eggs (helminths), which can cause diseases like cholera, typhoid, and schistosomiasis.

He noted that these pathogens can be transmitted to humans through direct contact with contaminated soil, ingestion of affected crops, or contaminated water sources. He added that human waste may also contain contaminants such as heavy metals, pharmaceuticals and other pollutants, noting however that faeces generally have lower heavy metal concentrations than some animal manures or sewage sludge contaminated by industrial effluents.

It was gathered that organisations like the World Health Organisation (WHO) have established guidelines for the safe use of human excreta in agriculture to mitigate health risks.

Further investigations showed that while human excreta offers potential benefits for soil fertility and a sustainable waste management solution, its use must be managed carefully to protect public health and the environment.

A soil scientist based in Abeokuta, Ogun State, Dr. James Orilowo, who confirmed the benefits of human excreta for soil fertility, said the most critical step for its adoption is proper treatment, such as composting, to eliminate or significantly reduce pathogens.

“Composting should ideally reach and maintain temperatures between 55-65°C for a specified period – at least three days and include a curing phase of several months to ensure pathogen die-off; and storing treated excreta for at least six months before application is recommended to reduce the risk of infection from soil-transmitted helminthes.

“Farmers should use personal protective equipment (PPE) such as gloves when handling waste; incorporating the manure into the soil and following specific days to harvest intervals; and clear regulations, public education, and support from agricultural extension agents are essential to promote safe practices and overcome socio-cultural taboos,” he said.

To buttress the position of these experts, researchers said the agricultural and horticultural use of excreta has the potential to promote the transmission of excreta-related diseases, especially if raw excreta are applied to the land. However, as in the case of wastewater use, it is now possible to design and operate excreta use schemes in which pathogen transfer via excreta-fertilised crops, including salad crops eaten raw, is eliminated.