Climbing Beans on Terrace Walls
3.2a - Climbing beans on terrace walls
Noah Dion, University of Guelph, Canada
Related video(s): Managing birds in climbing beans (Source: Access Agriculture)
Related video(s): Staking climbing beans (Source: Access Agriculture)
Related video(s): Wall crops (English) (Source: SAK Global)
Suggested citation for this chapter.
Dion, N. (2022) Climbing beans on terrace walls. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. farmpedia.org
Introduction to the Farming Practice
Terrace farming is a practice that has been exercised over the past 5000-6000 years, primarily in hilly, rural regions where there is not an abundance of flat farmland to cultivate. These terraces are utilized mostly by farmers in South Asia (e.g. China, India, Nepal, etc.), East Africa (e.g. Ethiopia, Tanzania, etc.), and South American regions (Chapagain et al., 2019). The terrace wall gives the farmer the ability to use poor farmland in mountainous regions by building risers up the hilly parts of the land, like a staircase. The terrace is made up of three main components: the flat land between each riser (step-up), which is cultivated mainly with field crops; the slim, narrow path on the edge allowing farmers to navigate the land and tend to the crops; and the riser, usually a bare wall either constructed with a sturdy material or dug out and man-made. In Nepal, for example, a terrace wall's dimensions are typically 4-5 m in height and 50-100 m in length, with the flat land between each step being roughly 3-4 m in width (Chapagain et al., 2019). This means that more than half the potential surface area is unused — in particular, the vertical surface. Growing crops, in particular climbing beans, at the base of the terrace wall offers an opportunity to improve local nutrition and the environment, and to alleviate poverty.
Climbing Bean Candidates for Cultivation on Terrace Walls
The legume family is the third largest family among all flowering plants, hosting approximately 20,000 different species (Doyle, 1994). Some examples of these legumes (more specifically, climbing beans) are the cowpea, common bean, and winged bean. There are many different types of climbing beans that are candidates for successful growth on terrace walls, and these could be planted at the base of the walls. The jack bean (Canavalia ensiformis) is a great example of a legume that would thrive in this environment. Native to the West Indies and Central America, these beans hold potential to grow on terrace walls because they are tolerant to both waterlogging and drought (Haq, 2011), and can survive on as little as 650 mm of rainfall per year (Clark and Raizada, 2017). The winged bean (Psophocarpus) is another potential candidate for climbing terrace walls. This crop shows potential based on its agronomic and nutritional traits and is usually grown by subsistence farmers; its seeds contain a significant amount of protein (37.3%) (Cerny et al., 1971). Unfortunately, this bean is very underutilized and lacks adequate research.
Benefits of Growing Climbing Beans on Terrace Walls
Implementing climbing beans into terrace farming will increase overall legume yields, which can lower poverty and malnutrition rates in hilly regions. Beans add nitrogen to the soil to assist other crops, as well as protein to food and fodder for human and livestock diets, respectively (Rondon et al., 2007). There are many benefits that make farming on terrace walls appealing. Terrace risers are designed to prevent erosion from rainwater by slowing the amount and velocity of rainwater collecting on the slope of the risers, which in turn slows the erosion process (Wheaton and Monke, n.d.). In addition, more efficient farming can be practiced through the wall's ability to collect and hold more water. In Nepal, the average agricultural land holding is about 0.68-0.77 ha in hilly/mountainous regions (Clark and Raizada, 2017), so incorporating terrace walls into crop production will greatly benefit subsistence farmers in these regions.
Potential Hardships
There are many challenges to consider when implementing this method of farming, as it can be very tedious and laborious (Clark and Raizada, 2017). The height and trajectory of the cultivated land on the terrace walls can make farming climbing beans very physically challenging, especially for smallholder women farmers, who are unfortunately not always as physically capable as a stronger male farmer in certain circumstances. The direction the wall faces is very important with respect to overall sun exposure. Climbing crops may shade the crops growing on the horizontal land between the terrace risers, which would interfere with the growing process. Also, once the sun is no longer shining on the face of the wall, the climbing legumes will lack sunlight. Climbing beans may not be compatible with other terrace crops or crop production methods (e.g. flooded rice paddies) (Clark and Raizada, 2017).
Socio-Economic Challenges
There are also socio-economic hardships to consider, since the hilly regions that terrace farmers populate typically suffer from poverty. In these regions, there can be a lack of human capital, since many men migrate to the city or other countries for employment (Chapagain and Raizada, 2017). In Nepal, over 30% of the population lives on $14 USD per month, and 75% of the population in hilly regions lives below the poverty line (Chapagain and Raizada, 2017). Therefore, constructing and maintaining terrace farms is not a very feasible option for economically struggling communities in these mountainous regions, and hence this practice would be limited to farmers who already have terraces.
Picture Based Lesson to Train Farmers
Practical Links to Get Started
References
1. Pratap, A., & Kumar, J. (2011). Underutilized food legumes: Potential for multipurpose uses. In A. Pratap and J. Kumar (Eds.), Biology and Breeding of Food Legumes. Cambridge: CAB International.
2. Cerny, K., Maud, K., Pospisil, F., Svabensky, O., & Zajic, B. (1971). Nutritive value of the winged bean (Psophocarpus palustris Desv.). British Journal of Nutrition, 26, 293-299.
3. Chapagain, T., Ghimire, B., Pudasaini, R., Gurung, K., Choi, K., Rai, L., Magar, S., Bishnu, B.K., & Raizada, M.N. (2019). The underutilized terrace wall can be intensified to improve farmer livelihoods. Agronomy for Sustainable Development, 39, 29. DOI
4. Chapagain, T., & Raizada, M.N. (2017). Agronomic challenges and opportunities for smallholder terrace agriculture in developing countries. Frontiers in Plant Science, 8, 331. Link
5. Clark, J.C., & Raizada, M.N. (2017). Climbing legumes: An underutilized resource with significant potential to intensify farming on terrace walls (FTW) for smallholder farmers. bioRxiv. Link
6. Doyle, J.J. (1994). Phylogeny of the legume family: An approach to understanding the origins of nodulation. Annual Review of Ecology and Systematics, 25, 325-349. Link
7. Rondon, M.A., Lehmann, J., Ramírez, J., et al. (2007). Biological nitrogen fixation by common beans (Phaseolus vulgaris L.) increases with bio-char additions. Biology and Fertility of Soils, 43, 699-708. DOI
8. Wheaton, R.Z., & Monke, E.J. (n.d.). Terracing as a "best management practice" for controlling erosion and protecting water quality. Purdue University, Cooperative Extension Service. Link