Page 1

Pioneering yam systems research for improved food security West Africa accounted for over 90 percent of yam production in 2014, yet soil degradation and climate change are having a significant impact on yields. More effective soil and crop management in yam systems could help improve crop productivity and boost food security and income, as Professor Emmanuel Frossard, the Principal Investigator of the YAMSYS project, explains Tuber crops grown throughout the tropics, yams are an important staple food for millions of people around the world and particularly in West Africa, where they hold high socio-economic and cultural importance. However, soil degradation in West Africa represents a significant threat to tuber yields, an issue that researchers in the YAMSYS project are working to address. “The idea behind the project is to investigate acceptable and feasible methods of improving soil fertility, in order to improve yam productivity,” explains Professor Emmanuel Frossard. The approach has been constructed together with stakeholders, with the goal of developing soil and crop management innovations which are adapted to the various socio-economic and cultural contexts of West Africa.


or disappear,” outlines Professor Frossard. Another major issue with current management methods is the retention of large quantities of the harvest for re-planting, which limits yields. “Traditionally, farmers typically use about a quarter of the harvest as the planting material for the next season,” says Professor Frossard.

The idea behind the project is to investigate

methods of restoring soil fertility, in order to improve yam productivity

Current yam cropping practices

Understand the diversity of yam systems

The soil itself needs to be highly fertile in order for yams to flourish in the first place, yet current crop management techniques lead to soil degradation. Traditionally, yams are grown after relatively long fallow periods without external inputs. “This means that the soil has been cultivated but then left for many years. We have found that farmers use this previously long-term fallow land because initially they can get high yields. According to farmers, repeated yam cultivation on the same plot rapidly leads to low crop yields. Furthermore, because of the increase in population density, the remaining surfaces under long term fallow decrease rapidly

The goal of developing acceptable and feasible methods to improve soil fertility and yam productivity starts with a proper understanding of the diversity of agroecosystems, and also of the prevailing socio-economic contexts. This is why the first step of the project in January 2015 was to characterise the existing soil, vegetation, and yam cropping systems across four sites in Burkina Faso and Ivory Coast. Alongside this work, researchers are also characterising these sites with respect to their socio-economic characteristics, investigating a number of questions.

“Which groups of people are present at a specific site? Are they native to the area or are they migrants? When did the migrants arrive? What is the relationship between the native people and the migrants? What is the most important crop? Is it yams, cocoa, or cotton?” asks Professor Frossard. The project will also characterize the agricultural extension systems in the two countries, aiming to learn more about the current strategies and operational goals of these institutions, and to design tools to be used in their national and regional outreach strategy for sustainable yam systems. This first step has already helped researchers to reach a deeper understanding of each of the sites, the yam consumption patterns and the local economic conditions more generally. For instance, in the centre and north of the Ivory Coast, yams are cultivated both for food and cash, while in the south of the country where cocoa is the main crop, yams are grown for self-consumption. “A lot of Baoulé people emigrated from the centre of Ivory Coast to the south of the country in the ‘80s to produce cocoa. This southwards movement of people is important, as Baoulé people traditionally consume a lot of yams, but they are less able to produce them now because most of the land is occupied by plantation crops such as cocoa. So they have to import tubers from areas where yams are still produced, which is expensive,” explains Professor Frossard.

EU Research

These are important factors to consider in terms of developing innovations that are relevant to local needs. “Farmers in the south of the country are extremely interested in our innovations, because they could help boost production and reduce their expenses for food,” says Professor Frossard.

Innovation Platforms The innovation platforms established at each of the four sites play a key role in the development of these innovations. These platforms bring together interested parties, including yam farmers, traders and administrative figures to consult and identify potential solutions to specific problems, which Professor Frossard believes will help the project to achieve a lasting impact. “When we design a specific type of innovation, we want to involve the people who can have an impact on the behaviour of farmers,” he explains. This could be micro-finance experts or national authorities, who may be able to heighten awareness and generate more interest. The dialogue established in these innovation platforms has allowed researchers to identify and rank the key bottlenecks in yam production, which are land scarcity, unpredictable rainfall, soil fertility depletion and bad quality yam planting material (yam seed). Since land scarcity and rainfall pattern are difficult to modify, it was decided at the innovation platforms to develop innovations to improve seed quality and soil fertility. Following these discussions, plots were established in 2016 at the four sites to demonstrate the production of high quality seeds. These plots have since been used as school fields to train farmers, and also as a source of planting material for farmers and the project.

Integrated soil fertility management Discussions in the innovation platforms allowed researchers to co-design innovations to improve soil fertility and yields. These innovations were developed in a site-specific manner using the concept

of integrated soil fertility management (ISFM). “When we speak about ISFM, we speak about using high quality yam seed of improved cultivars, adding commerciallyproduced mineral fertiliser with or without organic matter residues, and of growing yams in rotation,” outlines Professor Frossard. These innovations are currently being tested in field experiments conducted by the YAMSYS team. At the end of the first year, in Winter 2017, farmers evaluated the results, and some have already started to implement their preferred innovations in their own fields. The YAMSYS team does not intervene in the farmers’ field, but analyses how farmers modify their preferred innovations to suit their constraints and opportunities. The team also looks at how farmers record the tuber yields, analyses farmers’ attitudes vis-à-vis the innovation, and also assesses the economic benefit resulting from the innovations more generally. This approach could potentially be applied to other crops aside from yams. Yams themselves have not historically attracted a lot of research attention; the project is making an important contribution in these terms, helping to strengthen the research base. “A very important output from the project will be the training that we provide to a generation of students. They can then take the lessons from the project and apply them in their own communities,” says Professor Frossard. Over the longer term, Professor Frossard and his colleagues are considering how they can heighten awareness of the project’s results and influence soil and crop management beyond the four sites that were the initial focus in research. “We see both in Burkina Faso and the Ivory Coast that people working in the agricultural sector at a national level are showing an interest in our approach. We’ve even received proposals to work with them at national level, not just at the local level,” says Professor Frossard. “Thanks to the collaboration with these national organisations, we hope that it will be possible to upscale our approach to other situations.”

Yamsys Biophysical, institutional and economic drivers of sustainable soil use in yam systems for improved food security in West Africa Project Objectives

To develop innovations in the soil fertility management of yam systems in selected agroecological zones of West Africa, with the purpose to increase crop productivity, food security, income of the actors involved in the yam value chain and environmental sustainability.

Project Funding

The YAMSYS project (www. is funded by the food security module of the Swiss Programme for Research on Global Issues for Development ( (SNF project number: 400540_152017/1).

Project Partners

• Emmanuel Frossard, ETH Zurich, Switzerland • Beatrice Aighewi, International Institute of Tropical Agriculture, Nigeria • Séverin Aké, Université Felix Houphouët Boigny, Côte d’Ivoire • Urs Niggli, FiBL, Switzerland • Hassan Bismarck Nacro, Université polytechnique de BoboDioulasso, Burkina Faso • Daouda Dao, CSRS, Côte d’Ivoire • Lucien N. Diby, World Agroforestry Centre (ICRAF) • François Lompo, INERA, Burkina Faso • Johan Six, ETH Zurich, Switzerland

Project Coordination

• Valérie Kouamé Hgaza, CSRS Côte d’Ivoire • Innocent Kiba, ETH Zurich

Contact Details

Professor Emmanuel Frossard ETH Zürich Institute of Agricultural Sciences Research station Eschikon CH-8315 Eschikon-Lindau Switzerland T: +41 52 354 91 41 E: W:

Professor Emmanuel Frossard

Emmanuel Frossard obtained his PhD in agricultural sciences in 1985, from the INPL, Nancy, France. He is currently full professor of plant nutrition at ETH Zurich where he is conducting a process-oriented research to understand drivers controlling nutrient fluxes to contribute to the development of ecologically efficient agricultural systems.



More effective soil and crop management in yam systems could help improve crop productivity and boost food security and income, says Profess...