By Mudingu Joseph

2016 has been declared the International Year of Pulses by the United Nations. Common bean is the most important pulse crop in the world. This is more so in Rwanda. In this issue, we report a successful impact story of climbing beans in Rwanda. Clearly, beans are no longer a poor man’s meat.

They have become the green or vegetable meat of even the rich. Climbing beans are like other ordinary beans in nearly all respects. The difference is their inherent higher productivity, three-folds per unit area, than their bush counterparts. The world is pre-occupied with closing the agriculture genetic yield gaps. Climbing beans offer in-built solution to this. They are the pulse to watch. This is more so in Rwanda, where shortage of arable land is increasingly becoming acute. We commend RAB for its breakthrough in developing climbing bean varieties and related yield enhancing innovations that have contributed to the well-being of Rwandans.

However, farmers still report one sticking challenge to fully exploit productivity benefits from climbing beans: staking. We call upon researchers, policy-makers, development partners and investors to rise to this challenge. It will be when farmers can utilize affordable, environment friendly and cost-effective staking materials that adoption of climbing beans will translate in even better livelihoods in Rwanda and Africa. There is an old saying: "Seek knowledge, even if it means going to China”. This could as well be the direction to take in solving the equation of staking climbing beans. 

Augustine Musoni, a senior researcher and leader of the bean research team with Rwanda Agriculture Board (RAB) took The New Times through the science of story of climbing beans and its impacts on productivity and food security in Rwanda. He strongly believes climbing beans have had remarkable impacts on peoples livelihoods, but the potential is still under exploited. "Apart from quality seed, staking is a real issue” he sums it up.

Beans: a total crop

Beans are a priority crop in Rwanda, occupying the largest arable land and consumed by nearly all, the urban and the rural populations. It is regarded as a near-perfect or total crop due its multiple uses towards food, nutrition and incomes security. Most prominent is its contribution to protein and micro-nutrient nutrition, particularly among the rural smallholders. It is increasingly regarded as "green or vegetable meat” and a substitute for "red meat” for the wealthy.

Beans and environment protection

As a legume beans improve soil fertility through N-fixation. Bean residues complement animal feeds and organic manure production. Bean mulches suppress weeds, conserve soil moisture and micro-organisms and replenish soil nutrients as a whole. Climbing beans prevent hillside soil erosion nearly year-round; and may play a role in fixation of atmospheric C, important in adaptation and mitigation of climate change.

The bean story

 The wild ancestor of common bean was a climbing type. It was very prolific (high seed production). The twinning (climbing) ability, seeding, branching, rooting and tolerance to diseases and pests were features for survival in the thick tropical forests of Latin America where the common bean was domesticated more than 10,000 years ago. The climbing beans we grow today, has retained similar adaptive attributes of their progenitor. Beans came to Africa about 400 years, brought by explorers and missionaries, but they were not completely alien to Rwanda as pockets of wild and semi-wild climbing beans existed in the northern highlands (till now).

Bush versus climbing beans

 However, the lower yielding bush (dwarf) beans predominate in Rwanda and globally."I believe, the natural selection against the higher yielding climbers must have been influenced by the staking question. It was, aided by under population and unlimited land resources as well as under developed trade as production was for subsistence. This was more favorable for the bush beans”, Musoni says. However, the average land holding in Rwanda is less than a hectare today.

Enter climbing beans

However, as demographic dynamics continue to exert pressure on the already scarce land; as harsher environments arise from changing and varying climate and with the associated lurking food crisis, the need for intensified crop production is more real. "The fast-reversal to selection of the more resilient climbing beans will be a necessity and not an option” said Dr. Louis Butare, RAB Director General, also a bean scientist. Climbing beans produce up to 5 tons per hectare that is three times more than the bush types. They use more air space than land and are as effective as high-rise buildings in urban areas. In a way, climbing beans free some land on which complementary starchy crops are grown. By analogy, they stretch or expand arable land.

Adapted varieties

RAB (and ISAR) has released more than 30 climbing bean varieties in the last 5 decades. Fifteen were released more recently in 2010 and 2012. Besides higher yields (3.5 – 5.0 ton/ha), the varieties had better resistance and tolerance to prevailing diseases and climatic stresses such as drought. Others, especially the navy white, yellows, red kidneys and red mottled seed types fetched premiums on local and regional markets selling as much as twice to four times more than ordinary prices.

RAB released climbing bean varieties find way to the market

More recently, 8 of the released varieties were found to have higher contents of micronutrients, particularly iron and or zinc. These were intensively promoted for better nutrition and alleviation of anemia and other micro-nutrient malnutrition deficiencies, especially among children and women. The released varieties are adapted to the major production agro-ecologies in the country. Better still, many of the Rwandan varieties are adopted in many countries across Africa, where they were introduced.

Climbing beans and environment

To some, climbing beans damage environment as wood is cut to stake them. However, climbing beans technologies encourage afforestation and environment protection. Visit the North and North-western highland districts in Rwanda where climbing beans are endemic. The farmers were induced to growing of fast-growing and regenerating Pennisetum and leguminous N-fixing agroforestry species such as Lecaena, Calliandra, Gliricidia, and Alinus on well terraced top and hillsides to source the wood stakes. This artificial "climbing bean farming system” provides a vegetative buffer against loss of soil nutrients by erosion replenishes nitrogen and helps stabilizing the terraces. The prunes and residues from the trees and beans feed livestock for milk and manure production.  Old stakes provide cooking energy. Though they extract soil nutrients, climbing beans offer net benefits to preservation and sustainability of the same production ecosystems, not to mention food and other socioeconomic returns.

Staking challenges for farmers

Many farmers mention staking as a major challenge to growing climbing beans. This is more pronounced in the east where climbing beans are newly introduced and agro forestry is not as established. Ordinary farmers, therefore, lose 50 to 90% of their productivity potential, estimated at 5 tons per hectare. As better nutrition and global market demand for beans continues, overcoming this staking challenge would see Rwanda triple production and surplus beans for regional and overseas markets.

Addressing the challenges

 RAB recently developed an innovation that reduces wood stakes by 70% in combination with locally available trellises (strings, codes or fibers). The farmers welcomed and preferred the new innovation, mainly because they lacked wood, despite a yield margin of about 300kg/ha compared to exclusive use of wood. In science jargon, this was statistically insignificant. But as one farmer observed, this would be a huge gap, once extrapolated to the national acreage of beans, estimated at 450,000 ha.

So, what is the real solution to staking?

Even as research continues, we are calling upon investors to come up with smarter staking innovations, be it from "plastic” or "iron & steel” industry. I can foresee an insatiable demand for industrial stakes not only in Rwanda, but in Africa and beyond. Says Musoni Climbing beans occupy about 35% (~450,000 ha) of bean area in Rwanda .The total area under beans in Africa is about 4 million hectares, with climbing occupying a minute proportion. At 50,000 poles per hectare, it is easy to see real challenge for farmers, but also the potential opportunity for the investment in the business, as adoption of climbing beans expands.

Future of climbing beans

Traditionally Rwandans used to farm bush beans but today most grow climbing are taking over. In the late 1970s and early 1980s climbing beans were grown by 1 – 5% of farmers in the country. In the late 1980s, a combination of climatic factors and outbreak of bean diseases (root rots) wiped out all the farmers’ bush bean, especially in the cool, wet and humid highlands of the North, Northwest and South. Climbing beans became more resilient, and actually those same conditions were the most favorable for their production. Farmers maintained the few land races of the climbing beans they grew. And the research in the then ISAR, now RAB intensified breeding, release and dissemination of better resistant and tolerant climbing beans. Adoption of climbing beans is currently estimated at 65% in the country. It is close to 100% in many districts of the Northern Highlands.

Mid-altitude climbers

More recently, RAB released climbers suitable for the eastern and central low and mid-lands. Adoption is growing, but affected by the staking challenges.

Partnerships

Partnerships with development partners, notably the Alliance for a Green Revolution in Africa (AGRA) and CIAT/HarvestPlus, among others have been critical in the achievements and impacts of the climbing beans in Rwanda, and are here-by acknowledged, Musoni concludes.