Biochar-based fertilizers for improved food and nutrition security

To improve global food and nutrition security while staying within planetary boundaries, it is crucial to increase the production of nutrient-rich foods on existing agricultural lands in a sustainable way. Small family farms produce more than half of the world's food but often have low productivity due to a lack of fertile lands and inputs. They also often do not fully use the potential to provide fresh and varied food for household consumption. Innovative methods that improve soil fertility and water management without requiring expensive and energy-intensive inputs could leverage food production in small farms and improve food and nutrition security.

Biochar is a carbon-rich substance obtained when exposing biomass – such as wood, rice straw, or fallen leaves – to temperatures above 400°C in the near absence of oxygen, a process called pyrolysis. It is not the biomass itself that burns, but the flammable gases that evaporate from the biomass due to the fire's heat, leaving the carbonaceous backbone of the biomass intact. The resulting biochar is very porous, like a sponge, and has a huge inner surface that can hold nutrients, water, and other substances. Partners at Ithaka Institute have developed a method to produce high-quality biochar in low-cost, farm-scale soil pit kilns called Kon-Tiki.

Biochar improves soil fertility by retaining and exchanging water, nutrients, and air, as well as sustaining the build-up of soil organic matter in soil.  When mixed with organic substances like compost, liquid manure, urine, or fermented kitchen waste, biochar increases the fertilizing effect of these by retaining nutrients so the plants can access them. Urine is an excellent fertilizer but is underused because of odor and the necessity to mix it with nine parts of water. Biochar can soak up urine and transform it into a potent odorless solid fertilizer that can be applied without dissolving the urine in water.

With our partners, we seek to test and scale this technology. Our work began in the Food and Agricultural Approaches to Reducing Malnutrition (FAARM) project that evaluates how far an integrated home gardening, nutrition, and hygiene intervention can reduce undernutrition in women and young children. In our field site in northeastern Bangladesh, we found that urine-biochar fertilizers using cow urine are easy for farmers to produce and use by, virtually free of cost, and well accepted. Compared to usual farmer practice, yield benefits in vegetable gardens were substantial – ranging from 25% to 120% – and consistent across crop types, seasons, and production methods.

To help disseminate this technology to other projects within and outside of Bangladesh, we have produced a manual outlining the biochar-based fertilizer production process (see link below).

Project team:

External collaborators:

Hans-Peter Schmidt (Ithaka Institute, Switzerland)
Ipsita Sutradhar (James P Grant School of Public Health, BRAC University, Bangladesh)
Sayema Akter (James P Grant School of Public Health, BRAC University, Bangladesh)
Abdul Kader (Helen Keller International, Bangladesh)
Abul Kalam (Helen Keller International, Bangladesh)


The UK government funded the "Biochar-Urine Nutrient Cycling for Health" (BUNCH) project (2016-2017) through the Leveraging Agriculture for Nutrition in South Asia (LANSA) research consortium.

The Food and Business Applied Research Fund (ARF) of the Dutch Ministry of Foreign Affairs funded the Scaling-up "Biochar-Urine Nutrient Cycling for Health" in Bangladesh (BUNCH2Scale) project (2017-2020).


Waid, J.L., Schmidt, H-P., Gabrysch, S. (2022): Manual. How to make biochar-based fertilizer for improved food security and health. Potsdam, Germany.

Sutradhar, I., Jackson‑deGraffenried, M., Akter, S., McMahon, S.A., Waid, J.L., Schmidt, H., Wendt, A.S., Gabrysch, S. (2021): Introducing urine‑enriched biochar‑based fertilizer for vegetable production: acceptability and results from rural Bangladesh. Environment, Development and Sustainability.

Sutradhar, I., and Akter, S. (2017): Filthy Fertilizer: How Urine-Biochar Could Potentially Help Farmers in Rural Bangladesh. #VitalSigns.

Consortium publications:

Bird, F.A., Pradhan, A., Bhavani, R.V., Dangour, A.D. (2019): Interventions in agriculture for nutrition outcomes: A systematic review focused on South Asia. Food Policy.

Glover, D., Poole, N. (2019): Principles of innovation to build nutrition-sensitive food systems in South Asia. Food Policy.