Filthy Fertilizer: How Urine-Biochar Could Potentially Help Farmers in Rural Bangladesh

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Farmers producing biochar in a soil pit kiln.

Urine + Biochar = Quality Fertilizer. Biochar is created through burning biomass in an oxygen-limited environment. Biochar is a light and porous material with high adsorptive and water-holding capacity that can be used as fertilizer. The Ithaka Institute in Switzerland invented a low-tech method to produce biochar from crop and wood waste in soil-pit kilns (a type of oven). Studies have also demonstrated that animal (or human!) urine can be a highly efficient fertilizer. Even though it is available free of cost, urine remains underused in the global farming industry because of the bad smell and other associated socio-cultural barriers. However, most are unaware that biochar can actually soak up urine and transform it into an odorless solid organic fertilizer that promotes optimal soil conditions for farmers to grow crops.

Urine-Biochar Fertilizer in Bangladesh. In Bangladesh, the FAARM project promoted home gardening among small-scale farmers to improve their nutritional status. But the home gardens demonstrated low soil fertility and commercial mineral fertilizer was less affordable for the farmers. This is where the BUNCH project played a key role; it tested whether urine-biochar fertilizer could serve as a solution for the farmers to improve their home gardens at a low cost. But the real question was whether the farmers would accept it.

Cow Urine Already Accepted! Since cow dung is widely used in rural Bangladesh as fuel and fertilizer, we found that both Hindu and Muslim farmers under the project quickly accepted the concept of using biochar mixed with cow urine. In fact, they preferred using it because not only are the ingredients easily and freely available, but it is also chemical-free and highly efficient.

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Biochar and urine are mixed together in buckets before it is distributed in the soil.

Yuck! Human Urine is Considered “Impure.” When the study introduced the use of human urine with biochar, farmers from both Hindu and Muslim communities were very hesitant to use it due to their religious and cultural beliefs. Human urine is considered ‘impure’ and ‘unholy’ substance. They are also convinced that human urine is accountable for spreading diseases, although the scientific literature does not support this. Some Hindu farmers were even afraid of social isolation and some Muslim farmers thought that crops produced by using human urine would be religiously forbidden to consume. Only a few individuals were willing to try the human urine-biochar as they thought it was possible to overcome the impurity-related barriers by taking a bath and changing clothes immediately after handling the fertilizer.

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Urine-biochar fertilizer being applied to the soil before planting.

What Next? Since using urine-biochar for crop production is a new concept in Bangladesh, a series of practical demonstrations were very helpful for training farmers to manufacture and use it. At the moment, further testing of the method is underway in the field. The crop yields from urine-biochar will be compared to yields from traditionally used fertilizers and chemical fertilization.

In general, using urine-biochar fertilizer can help increase food security and cropland diversity in areas with severely depleted soils, scarce organic resources, and inadequate water and chemical fertilizer supplies. With wider promotion and use, it will eventually become easier to convince more farmers in Bangladesh to tap into the rich supply of human urine and biochar-based fertilizer.

This blog is written by Dr Ipsita Sutradhar and Sayema Akter. They are both research associates at BRAC School of Public Health.

This blog was written as a result of research funded by LANSA Research Programme Consortium under the Responsive Window 2 opportunity. LANSA is funded by the UK Government. The views expressed in this document do not necessarily reflect the UK Government’s official policies.


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