Economic analysis of seed yam production systems in Nigeria

New seed yam systems from minisetts, minitubers and vine cuttings have been developed for yam production to supplant the traditional systems, which have proven inefficient and costly. The new techniques provide producers in tropical countries with the opportunity to minimize production costs, reduce seed yam price and promote greater seed availability. A discounted cash flow budget with a whole farm perspective was used to analyse the economic performance and risk implications of a hectare investment in the new seed yam system over time for a representative farm. Data based on realistic process costs and review of past reported studies were employed to reflect the relative economic worthiness and opportunity cost of investment and operating capital of seed yam systems in Nigeria. From the net present value (NPV) and benefit:cost ratio (BCR) analyses, the new seed yam production systems were more viable than current traditional seed yam production systems through milking of live immature plants. This raises the need to identify which among the new production techniques could be the most profitable and recommendable. Therefore, understanding the economics of seed yam production systems would not only help a significant proportion of local, regional and national stakeholders but also assist the policymakers, funding agencies and other organizations involved in yam projects and programmes

The Challenge of Improving Soil Fertility in Yam Cropping Systems of West Africa

Yam (Dioscorea spp.) is a tuber crop grown for food security, income generation, and traditional medicine. This crop has a high cultural value for some of the groups growing it. Most of the production comes from West Africa where the increased demand has been covered by enlarging cultivated surfaces while the mean yield remained around 10 t tuber ha−1. In West Africa, yam is traditionally cultivated without input as the first crop after a long-term fallow as it is considered to require a high soil fertility. African soils, however, are being more and more degraded. The aims of this review were to show the importance of soil fertility for yam, discuss barriers that might limit the adoption of integrated soil fertility management (ISFM) in yam-based systems in West Africa, present the concept of innovation platforms (IPs) as a tool to foster collaboration between actors for designing innovations in yam-based systems and provide recommendations for future research. This review shows that the development of sustainable, feasible, and acceptable soil management innovations for yam requires research to be conducted in interdisciplinary teams including natural and social sciences and in a transdisciplinary manner involving relevant actors from the problem definition, to the co-design of soil management innovations, the evaluation of research results, their communication and their implementation. Finally, this research should be conducted in diverse biophysical and socio-economic settings to develop generic rules on soil/plant relationships in yam as affected by soil management and on how to adjust the innovation supply to specific contexts