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.
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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.
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