A simple but innovative use of trees is contributing to high-yielding and nutritious beans in Rwanda.

In Rwanda, the demand for adequate and nutritious food continues to rise as the population increases. The country is also stepping efforts to fight malnutrition that leads to childhood stunting, affecting 38 percent of children under five years as indicated in the 2014–15 Rwanda Demographic and Health Survey. Beans are a rich source of proteins. The improved varieties contain essential micro-nutrients, such as iron and zinc, and offer an inexpensive way as part of efforts to end hunger and undernutrition in Rwanda by 2025.

Beans feature prominently in the diets of Rwanda households. The Food and Agriculture Organization of the United Nations estimates bean consumption at 29 kilograms per person per year. Growing climbing beans, which occupy less space and yield two-to-three times more than bush beans, is one way of meeting the demand, overcome malnutrition and improve the livelihoods of smallholders.

 ‘The higher yielding beans are also preferred as they grow faster, are tastier and fetch more than bush beans,’ said Jean Damascene Ndayambaje of Rwanda Agriculture and Animal Resources Board (RAB).  ‘Moreover, they require a smaller land space, which is a great relief to the residents of Rwanda where lack of arable space is a huge constraint to agricultural production.’ 

Successful establishment of climbing beans requires strong stakes to hold the additional weight as they grow and produce pods. Staking is recommended before the beans form tendrils to avoid contact with the soil, which would result in rotting of the pods and lower yields. However, high prices and lack of quality staking materials hinder growing of climbing beans. For instance, a bundle of 40 Alnus acuminata stakes costs about USD 4 while that of 45 napier grass (Pennisetum purpureum) about USD 1.60. The cost varies depending on the species from which the stakes are derived and distance from the source.

In search of options, farmers resort to overgrown napier grass, maize stalks and, in some cases, sorghum and cassava as stakes. These options are unreliable as the stems become weak and easily break from insect attacks and harsh weather conditions, such as heavy rains or strong winds. Besides, napier grass is also in high demand as fodder because many poor rural households own at least one cow per family thanks largely to the Government’s Girinka program to curb malnutrition through milk consumption and to improve productivity of the land with animal manure.

To address this challenge, the ICRAF-led Trees for Food Security project funded by the Australian Centre for International Agriculture Research (ACIAR) tested and then promoted the use of multipurpose agroforestry tree species — Acacia augusitissima, Alnus acuminata and Vernonia amygdalina — as a low-cost sustainable solution to provide stakes for climbing beans in Nyabihu and Rubavu districts. In addition, the project introduced climbing beans growing in semi-arid Bugesera District and also promoted Gliricidia sepium and Calliandra calothyrsus as other trees that could be used for staking.

The choice of trees was based on information generated through the Interactive Suitable Tree Species Selection and Management Tool. The tool helps to evaluate the suitability of trees by matching the environmental conditions of the area, associated products and ecological functions of the species and the socio-economic contexts of the farmers.

Findings from field experiments show that Acacia angusitissima, Alnus acuminata and Vernonia amygdalina attained heights of 1.4 m, 1.2 m and 1 m, respectively, three months after planting. Within 12 to 18 months, pruning could be done to obtain stakes of the right length of at least 2 m. The stakes can sustain the beans between 4 to 6 seasons before needing replacement.

Through the rural resource centres established by the project, farmers are able to access quality seedlings, acquire training in tree growing and management on farms. Over 2050 households have benefited from the tree seedlings for stakes as well as other tree products and services. Farmers also received training on agronomic practices, such as preparation of land, correct spacing, pest and diseases management and proper staking geared towards increasing yields from the climbing beans.

Besides the stakes, the fast-growing trees have become an affordable of source of green manure and mulch that helps to retain nutrients and moisture in the soil, hence, improving fertility of the land. They also contribute to erosion control, particularly, on steep slopes and radical terraces. Other than napier grass, families have additional protein-rich fodder for their livestock. Acacia, Calliandra and Vernonia are preferred by farmers keeping dairy cows and goats to boost milk production. The old stakes are used as fuelwood.

Feedback has been obtained from farmers who have incorporated trees on their farms for stakes. One such farmer is Joseph Desiree, a resident of Karago sector, Nyabihu District.

‘Currently, I have planted 60 trees comprising of 35 Alnus, 15 Acacia and 10 Vernonia,’ he said. ‘Before using the new stakes, I could only manage to harvest 20–25 kilograms of beans from my 1.2 acre piece of land. After using Alnus-derived stakes, I now harvest 40–50 kilograms of climbing beans per acre on average. This is enough to consume at home, sell at the local market and retain as seeds for the next planting season.’

In addition to making an impact on individual households, the project has also contributed to government priorities, notably the Bonn Challenge, with which Rwanda is working towards restoring degraded land through a mix of interventions, including agroforestry, targeting 2 million hectares by 2020. This has provided an opportunity for increasing tree-growing on farms, offering multiple benefits.

‘Apart from improved food security and nutrition, promoting appropriate tree-growing with commensurate on-farm management options also spares the forests from destruction as well as women and children from the laborious task of searching and collecting the hardy stakes,’ said Catherine Muthuri, the Trees for Food Security project manager and regional coordinator of ICRAF’s Eastern and Southern Africa Region.

Additional reporting by: Ruth Kinuthia, Anne Kuria, Alex Mugayi, Joseph Gafaranga and Providence Mujawamaria

For more information about the Trees for Food Security Project, please contact:

Catherine Muthuri

E-mail: c.muthuri@cgiar.org

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Mukuralinda A, Kiptot E, Twagirayezu D, Muthuri C, Musana BS. 2016. Alnus acuminata. Factsheet. Nairobi, Kenya: World Agroforestry (ICRAF).

World Agroforestry (ICRAF) is a centre of scientific and development excellence that harnesses the benefits of trees for people and the environment. Knowledge produced by ICRAF enables governments, development agencies and farmers to utilize the power of trees to make farming and livelihoods more environmentally, socially and economically sustainable at multiple scales. ICRAF is one of the 15 members of the CGIAR, a global research partnership for a food-secure future. We thank all donors who support research in development through their contributions to the CGIAR Fund.