Biochar as soil amendment

The majority of the people living in sub-Saharan Africa earn their living mainly by farming. Infertile soils and variable climate make it difficult to reach sufficient crop yields every year and therefore food security can be low. Soil quality reduction due to erosion and nutrient depletion due to l...

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Detalles Bibliográficos
Autores principales: Alvum-Toll, Kajsa, Karlsson, Tellie, Ström, Helena
Formato: First cycle, G2E
Lenguaje:sueco
Inglés
Publicado: 2011
Materias:
Acceso en línea:https://stud.epsilon.slu.se/2572/
Descripción
Sumario:The majority of the people living in sub-Saharan Africa earn their living mainly by farming. Infertile soils and variable climate make it difficult to reach sufficient crop yields every year and therefore food security can be low. Soil quality reduction due to erosion and nutrient depletion due to limited addition and maintenance of nutrients is a common problem. One feasible measure to increase soil fertility is addition of biochar, charcoal produced during pyrolysis (organic material, usually wood, heated under low oxygen conditions), which generally is used as fuel for cooking. This Minor Field Study is a BSc thesis based on studies of biochar as soil amendment in Kenya. The project had three main objectives. The first aim was to, through visits, describe smallholder farming systems in three areas in Western, Central and Eastern Kenya. Interviews, observation and sampling of characteristic organic materials were performed in each area. The second aim was to measure whether biochar application to soil can increase crop yields and if so, if there are any differences between biochar originating from different feedstock organic materials. The third aim was to return to the involved farmers and discuss and present the results as well as the possible practical benefits. All the visited farms were small-scale systems with no or few external inputs. The farming systems were similar in all three areas, though some differences were found, e.g. dominating types of crops. Most of the farmers were interested in using biochar as soil amendment- if it would be proven to have beneficial effects and be economically viable. The results from analyses showed that nutrient concentration correlated with the yield from pot trials where three treatments stood out: biochar from cassava stems, coffee leaves and fresh banana leaves. Biochar from these materials in general had the highest nutrient concentration as well as pot trial crop yield, indicating a fertilizer effect. Plant materials with different properties may be important for plant growth, but biochar rate seems to be a more significant factor, confirmed by the statistical test. The great need of improvement in soil fertility and the farmers’ interest towards biochar indicate that this approach might be possible to use in the future. However, more research on the subject is necessary if it is going to be implemented in the field, since these farmers cannot afford failures.