Biochar production and application in small-scale farming in Kenya: Yield increases and local perceptions

Research output: Contribution to conferenceAbstract


Degradation of agricultural soils and forest resources are two pervasive challenges in rural landscapes of sub-Saharan Africa. Biochar-producing biomass gasification technologies attract evermore interest because these can empower small-scale farmers to produce energy and food more sustainably by
improving energy use efficiencies, lowering emissions and strengthening climate resilience. In order to assess the potential impacts and the feasibility of soil biochar amendments we are carrying out on-farm trials with 150 households in three agroecosystems in Kenya. A participatory approach was followed for testing uptake of gasifier cook stoves and effects of biochar use on crop production. The outcomes that will be presented include: (a) the degree of feasibility, (b) the effects on crop yields, (c) the general attitudes towards the idea of using the cookstoves to produce biochar, and (d) patterns of biomass fuel use. Effects of domestically produced biochar, at rates of 1-10 t DW ha-1, on the production of maize (Zea mays) and kale (Brassica oleracea) were compared with normal farming practices. At the site located in Kwale the yield increases of maize showed a strong positive correlation with biochar dose. In the first season, yields increased from 0.9 Mg ha-1 in the control plot to 4.4
Mg ha-1 in average in the biochar-amended plots. At another site (Siaya), an average biochar dose of 2.8 Mg ha-1 lead to an increase in maize yields from 2.9 to 3.8 Mg ha-1 in average in the first season and from 1.7 to 2.5 Mg ha-1 in the second season after biochar addition. Findings from this action research indicate that producing and using biochar on small-scale farms offers suitable opportunities to close yield gaps across Kenya and in similar agro-ecological environments.


  • Yahia Mahmoud
  • James K Gitau
  • Erik Karltun
  • Thomas Kätterer
  • Geoffrey Kimutai
  • Mary Njenga
  • Gert Nyberg
  • Kristina Roing de Nowina
  • Dries Roobroek
  • Cecilia Sundberg
External organisations
  • University of Nairobi
  • Swedish University of Agricultural Sciences
  • World Agroforestry Centre
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Social Sciences Interdisciplinary


  • Biochar, Soil carbon mineralisation, Sustainable development
Original languageEnglish
Publication statusPublished - 2019 Sep 25
Publication categoryResearch
EventAgricultural Research for Development Conference 2019: Zero hunger by 2030, our shared challenge! - Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
Duration: 2019 Sep 252019 Sep 26


ConferenceAgricultural Research for Development Conference 2019
Abbreviated titleAGRI4D 2019
Internet address