Comparative Assessment of Indigenous Methods of Sweet Potato Preservation among Smallholder Farmers: Case of Grass, Ash and Soil based Approaches in Zimbabwe

by Edward Mutandwa and Christopher Tafara Gadzirayi


Lack of suitable storage facilities among smallholder farmers continues to expose farmers to intermittent food shocks. Farmers are thus making use of locally available preservation methods, derived from indigenous knowledge systems (IKS), to improve storability of sweet potatoes. However, not much is known about their efficacy in maintaining the quality of the stored crop. Thus the broad objective of this research was to assess the effectiveness of using soil, ash and grass as means of preserving sweet potato variety Mozambican White. The three mediums were tested over a period of 5 months and each treatment had two replicates. Three kilogram of soil, two kilogram ash and one kilogram grass were used for the analysis and the quantities were informed by local smallholder farmers. The experiment was conducted at ambient room temperature. Two parameters were monitored, the rate of discoloration of tubers and weight change over time. The results indicate that if quality of the stored crop and weight variation of tubers is considered, then use of soil banks is the most effective. However, weights of tubers for ash and grass were not statistically different from the soil treatment but some tubers were discolored. If farmers are to get the best results, a combination of the above techniques, particularly ash and soil, is recommended.

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Edward Mutandwa is a lecturer in the Department of Agriculture at Bindura University of Science Education. He has been involved in research for NGOs such as ITDG Southern Africa, particularly the Women in Construction Project and Knowledge and Information Systems Project in Epworth. He has worked as an Operations Research Consultant in ITDG Southern Africa.

Christopher Tafara Gadzirayi is a lecturer in the Department of Agriculture and Environmental Science at Bindura University of Science Education. He has extensive experience in research work ranging from supervisory management, environmental management and education and training.