Great Potential: Human Faeces as Fertiliser in Agriculture
In In a three-year trial phase, a research team at
HU research team tested hygienised faecal compost and
nitrified urine nitrified urine fertiliser on maize plants –
among others including in the greenhouse on the HU
campus in Berlin-Dahlem campus. Photo: Jan-Ole Boness
Human faeces have great potential for being used as a fertiliser in farming. They contain many valuable nutrients that are relevant for soil and plant growth. These include phosphorus, for example, a substance that plants need to grow and thrive, and which has been used as a fertiliser in agriculture since the 19th century. If fertiliser could be recycled from faeces, it would be possible to partially avoid its synthetic fabrication and also the mining of phosphorus, thus conserving resources. However, due to national regulations, fertilisers made from human excrement are currently only allowed for research purposes and not in farming.
Faecal Compost and Liquid Fertiliser from Urine Effectively Supply Plants with Nutrients
A team of scientists from Humboldt-Universität zu Berlin (HU), led by Prof. Dr. Timo Kautz, HU, and Prof. Dr. Roland Hoffman-Bahnsen from Eberswalde University for Sustainable Development, has now tested novel fertilisers derived from human faeces for the first time in agriculture during a three-year trial phase. Maize plants were treated with compost made from human faeces and with a liquid fertiliser obtained from human urine. The results: The faecal compost turned out to be an effective phosphorus fertiliser. When the compost was applied, the concentration of soluble phosphorus in the soil increased significantly, which was also reflected in the phosphorus content of the plants. A similar picture emerged for the supply of the plant nutrient potassium. On the other hand, the urine fertiliser proved to be an effective nitrogen fertiliser. The plants were well supplied with nitrogen, although the biomass yield was somewhat lower compared to the plants treated with chemical-synthetic nitrogen fertiliser.
Data Basis for Re-evaluation of Approved Fertiliser Ingredients
The research results published in the journal Soil Use and Management provide an initial data basis for evaluating the fertilising effects of compost made from heat-treated human faeces, as well as nitrified (i.e. fertiliser converted into ammonium and nitrate with the help of bacteria) urine liquid fertiliser. "Based on the data collected, we can say that these fertilisers, as natural products, can be a useful addition to the nutrient cycle in agriculture," says Jan-Ole Boness, who planned the series of experiments and conducts research at the Thaer-Institute of Agricultural and Horticultural Sciences at HU, Department of Crop Science. "This data provides an initial basis for adjusting the national fertiliser regulation,meaning the inclusion of human excrement in the list of approved ingredients." In a next step, the researchers want to use the data to investigate and evaluate other properties of the novel recycled fertilisers, such as possible soil contamination, especially with pathogens, and climate impacts.
The Test Series
The test series was realised in cooperation with the Kreiswerke Barnim, a municipal waste management firm, and the company Finizio. Finizio is based in Eberswalde near Berlin and specialises in ‘refining’ human faeces into fertiliser through composting and making it available for research. The material for the test series was the contents of dry toilets, which are used, for example, at major events on streets or in allotment gardens. The faeces were heated in a container for seven days and then composted to kill pathogens. This hygienised compost and the nitrified urine fertiliser were used in experiments in the laboratory, in the greenhouse, at the HU's teaching and research station in Thyrow, and in the field on partner farms.
Further Information
Research article in Soil Use and Management: Fertilizer addition effect of novel recycling fertilisers from human excreta in a pot experiment with maize (Zea mays L.)
Contact
Jan-Ole Boness
Thaer-Institute of Agricultural and Horticultural Sciences at Humboldt-Universität
Phone: +49 3334 657-286
bonessol@hu-berlin.de
Prof. Dr. Timo Kautz
Thaer-Institute of Agricultural and Horticultural Sciences at Humboldt-Universität
Phone: (030) 2093-46470
timo.kautz@hu-berlin.de