Participatory trials of on-farm biochar production and use in Tamale, Ghana
Urban agriculture is characterized by fast rotation of cropping cycles and high inputs and outputs on relatively small areas of land. Depletion of soil organic carbon and low nutrient use efficiency are severe agricultural constraints in the sandy soils of West Africa. We hypothesized that such an intensive system would provide ideal preconditions for the use of biochar, that biochar would enhance yields in urban horticulture, and that farmers would be able to produce biochar for on-farm use in Tamale, Ghana. Therefore, we studied the opportunities and challenges of biochar using a semi-participatory research approach. Working with 12 participant farmers, we defined research questions which were relevant to their livelihoods and collected qualitative and observational data, which determined the selection of variables to measure quantitatively. Different quality parameters such as leaf color and stiffness of lettuce were important to farmers and marketers when assessing the agronomic benefits of biochar. By adding biochar to their normal agricultural practice farmers were able to increase lettuce yields by 93%. This remarkable increase might be partially caused by farmers’ improved management of biochar plots: they concentrated their resources where they expected to yield the largest returns. Using a simple top-lit updraft gasifier, a special chimney for rice husk carbonization, it was relatively simple for farmers to produce biochar in the field, with an efficiency of 15–33%. These stoves’ payback times were between 1 and 2 months. Yet, rather than the efficiency of the carbonization technology, often emphasized in biochar research, the availability of feedstock and labor considerations determine the technology selected by farmers for biochar production. This is a novel approach to considering the economic realities of farmers in a semi-participatory appraisal where farmers both produce and apply biochar. This is crucial in order to understand and identify meaningful and economically viable uses of biochar.
KeywordsBiochar Lettuce Organic carbon Rice husk Soil fertility Urban agriculture West Africa
Thanks to the participant farmers at the New Dam site in Tamale (Ghana), the marketers who bought their lettuce and particularly the facilitator farmer Mr. Shani. This work was carried out as part of the UrbanFoodPlus Project “African-German partnership to enhance resource use efficiency in urban and peri-urban agriculture for improved food security in West African cities", funded by the German Federal Ministry for Education and Research (BMBF) under the initiative GlobE – Research for the Global Food Supply, grant number 031A242- A, B, C.
- BiocharPlus (2015) Educative Brochure: BiocharPlus - Energy, health, agricultural and environmental benefits from biochar use: building capacities in ACP countriesGoogle Scholar
- Brewer CE (2012) Biochar characterizatoin and engineering. Dissertation, Iowa State University, Iowa, USAGoogle Scholar
- Gyasi E, Fosu M, Kranjac-Berisavljevic G, Mensah A, Obeng F, Yiran G, Fuseini I (2014) Building urban resilience: Assessing urban and peri-urban agriculture in Tamale, Ghana. Nairobi, KenyaGoogle Scholar
- Häring V, Manka’abusi D, Akoto-Danso EK, Werner S, Atiah K, Steiner C, Lompo DJP, Adiku S, Buerkert A, Marschner B (2017) Effects of biochar, waste water irrigation and fertilization on soil properties in west African urban agriculture. Sci Rep 7(1):10738. https://doi.org/10.1038/s41598-017-10718-y CrossRefPubMedPubMedCentralGoogle Scholar
- Kimetu JM, Lehmann J, Ngoze SO, Mugendi DN, Kinyangi JM, Riha S, Verchot L, Recha JW, Pell AN (2008) Reversibility of soil productivity decline with organic matter of differing quality along a degradation gradient. Ecosystems 11:726–739. https://doi.org/10.1007/s10021-008-9154-z CrossRefGoogle Scholar
- Lambrou Y (2001) A typology: participatory research and gender analysis in natural resource management. Working document. Consultative Group on International Agricultural Research, Future Harvest M4 - Citavi, Cali, ColombiaGoogle Scholar
- Le Bissonnais Y, Arrouays D (1997) Aggregate stability and assessment of soil crustability and erodibility: II. Application to humic loamy soils with various organic carbon contents. Eur J Soil Sci 48(1):39–48. https://doi.org/10.1111/j.1365-2389.1997.tb00183.x CrossRefGoogle Scholar
- Mugwe J, Mugendi D, Mucheru-Muna M, Merckx R, Chianu J, Vanlauwe B (2009) Determinants of the decision to adopt integrated soil fertility management practices by smallholder farmers in the central highlands of Kenya. Exp Agric 45(1):61–75. https://doi.org/10.1017/S0014479708007072 CrossRefGoogle Scholar
- Novak JM, Busscher WJ, Watts DW, Amonette JE, Ippolito JA, Lima IM, Gaskin J, Das KC, Steiner C, Ahmedna M, Rehrah D, Schomberg H (2012) Biochars impact on soil-moisture storage in an ultisol and two aridisols. Soil Sci 177(5):310–320. https://doi.org/10.1097/SS.0b013e31824e5593 CrossRefGoogle Scholar
- Steiner C (2016) Considerations in biochar characterization. In: Guo M, He Z, Uchimiya SM (eds) Agricultural and environmental applications of biochar: advances and barriers, SSSA special publication, vol 63. Soil Science Society of America, Inc., Madison, pp 87–100. https://doi.org/10.2136/sssaspecpub63.2014.0038.5 Google Scholar