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Huge potato yield gap in Sub-Saharan Africa needs the private sector to fix it!

By Dieudonné Harahagazwe, Independent Consultant
August 2018

The impact of increasing population on food demand is expected to be accentuated in Sub-Saharan Africa (SSA) as it is expected to account for half of the world population increment by 2050 compared to one fifth in 1999. In this regard, the potatoes, the third most important food crop after rice and wheat, play a key role in feeding SSA. An analysis of FAO statistics from 1994 (year of reference) through 2014 shows that potato production in twelve SSA countries increased three fold due to expansion in production areas but with little change in tuber yields (see figure below). In countries like Angola and Nigeria, the potato area significantly increased – by 34 and 20 times, respectively – but at the expense of average tuber yields.

Changes in potato statistics (area harvested and yield ratios) over 20 years (1994 – 2014) of twelve countries from Sub-Saharan Africa. Source: Author, data from FAOSTAT

The total potato production from SSA (excluding Malawi for lack of reliable data) represents 44.7 % of total potatoes produced on the continent but harvested on a relative large area (71.8 %). A recent study conducted by the International Potato Center (CIP) and its partners showed that this level of production could be increased by 140% if identified causes of yield gap were addressed.

The yield gap magnitude

In the above CIP study, the yield gap is defined as the difference between the research yield and the potential yield, whereas the absolute yield gap is derived from the difference between the average farmer’s yield and the potential yield. The difference between average farmer’s yield and research yield is named farmer’s yield gap and it is the easiest to fill. One of the key findings of the yield gap study showed that smallholder potato farmers in SSA lose 24 t of achievable yield every time they harvest 1 ha and take home only 8 t. In other words, farmers are getting only a fourth of what they could produce.

Major yield gap causes

As an integrated part of the above CIP study, a 6-month online survey outlined eleven most important yield gap challenges which cut across all the three potato agro-ecologies of SSA (highlands, mid-elevation and subtropical lowlands). Those challenges are defined as follows: poor seed quality, bacterial wilt, poor soil health, late blight, lack and/or inappropriate use of fertilizers, viruses, sub-optimum use of lime, low yielding varieties, pests, limited knowledge on the crop and poor timeliness of operations. To illustrate the importance of these challenges, we could for example use the results of a potato fertilization trial conducted by CIP in Sussundenga, Mozambique in winter 2012. In this experiment, the variety Lulimile produced up to 38 t/ha under sprinkler irrigation and fertilization against 15 t/ha for the control (same variety and irrigation scheme but without fertilizers).

Framers’ group members visiting their seed potato field established in Rotanda, Mozambique in winter 2012, with the facilitation of CIP and an international NGO called Canadian Hunger Foundation (CHF). Photo credit: D. Harahagazwe

What are the solutions

Closing the potato yield gap in SSA requires addressing all those challenges through an integration of four key entry points, namely (1) clean seed of preferred varieties, (2) fertilizers, (3) pesticides and (4) knowledge sharing. In this regard, all potato stakeholders must play their part, including policy makers, regulatory institutions, extension, funding institutions, researchers (national, regional and international), private sector, NGOs, agro-dealers, farmers, traders, and financial institutions. Here we emphasize the critical role of the private sector in establishing and sustaining strong potato value chain built on higher yields and viable input and output market linkages. According to another recent CIP study on early generation seed (EGS) potato carried out in seven SSA countries and funded by the CGIAR Research Program on Roots, Tubers and Bananas (RTB), private companies play an important role in the supply of high quality seed at scale. That is the case of Kisima Farm in Kenya, Mtanga Foods Ltd in Tanzania, Horizon SOPYRWA in Rwanda and Organization for Rehabilitation and Development of Amhara in Ethiopia (ORDA). These companies invested in the seed sector in their various capacities, including tissue culture laboratories (ORDA), protective structures (0.5 ha computer-assisted greenhouse at SOPYRWA), mechanization, cold storage (2,000 t at Kisima Farm), etc. This explains partially the potato minituber boom – tenfold increase in ten years – which is taking place in SSA as reported in the same EGS study.
Private companies are also important in developing and selling supplies for tissue culture and plant pathology laboratories. With regard to fertilizers and pesticides, the major role is played by private companies. Currently two companies are present in most of SSA countries, namely Yara International ASA for chemical fertilizers and Syngenta AG for pesticides. Farmers’ training (fourth entry point) is being provided by international (e.g. CIP) and national research institutions, extension services and NGOs (e.g. Agriterra in Rwanda and Uganda). What is currently missing is how all these actors come together and coordinate their plans and actions. This bottleneck could be overcome by establishing strong multistakeholder platforms at various levels (local, national, regional and international). The World Potato Congress should play a key role in bringing the private sector players into these platforms and create win-win scenarios in many potato producing areas of SSA.