Vermicomposting as an effective source of organic fertilisers and an entry point to introduce other adaptation and resilience innovations for small farmers in Cameroon
By Emmanuel Ngungoh
To tackle the challenges related to climate change in Cameroon, the Climate Literacy into Mitigation and Adaptation (CLIMA) Project aims to enhance climate literacy for community members, government officials and other relevant stakeholders in order to establish a solid platform on which to design effective and tailored adaptation initiatives, build resilience and initiate transformation change.
Part of the action research component of CLIMA is to determine whether vermicomposting is an effective source of organic fertilisers and whether it offers an entry point for circular economy innovations that enhance adaptive capacity and resilience of small farmers in Cameroon.
The main research question is whether vermicomposting can be introduced successfully in the project area in Cameroon and what lessons and insights can be incorporated into the iterative process to enhance the technology and make it work within the context of the project area and to be replicated in other areas of the country subsequently. The second question is whether the technology is beneficial to the project beneficiaries and whether it is more effective, efficient and appropriate than the alternative options of chemical fertilisers and not applying fertilisers at all.
Methodology and Process
To establish the vermicomposting, we chose a site that had shade with no direct sunlight. After experimenting with different organic materials the group decided to use banana trees as the leaves and stems are easily digestible by the worms. Cut banana tree chunks were piled up in tight rectangular bunches. We then introduced partially decomposed cow dung of 45 to 60 cm high to serve as initial food source for the African night crawler earthworms species selected, 2 kg of which were applied for a bed of 6ft long, 3 ft wide and 2 ft high.
For the monitoring and evaluation of the effectiveness and the benefits of the technology, a randomised trial experiment was designed, dividing one section of the farm into blocks of 3 metres by 2 metres each. In the first block we applied the vermicompost and planted the maize at the specified planting spacing. In the second block we applied 40% less vemicompost and maintained the same spacing. In the third block we applied NPK fertiliser often used by the farmers. Finally, we applied no manure to the fourth block as a control. In order to minimise error in attributing cause and effect we attempted a randomised trial, by repeating the blocks three additional times so that we had four of each of the blocks in different areas on the farm. We observed and tried to measure differences at germination, tesseling and finally at harvest. At harvest the produce from each of the blocks was weighed.
Participatory Action Research
Participatory action research (PAR) is a reflective process of progressive problem-solving led by individuals working with others to improve the way they address issues and solve problems. PAR is generally applied within social learning contexts, where multiple actors collectively construct meanings (problem definition, objectives) and work collectively toward solutions (Maarleveld and Dangbégnon 1999; Pretty and Buck 2002). As for the limited predictability of climate change and limitations in local and scientific knowledge, PAR can strengthen understanding by building upon the complementarities of local and scientific knowledge and fostering a more nuanced understanding of systems.
The vermicomposting technology option adopted was relatively straightforward and easy to understand by the farmers. The issues that remain to resolve include the problem of transporting and the availability of the organic material, if they are to be acquired from farther away sites, given that household waste does not yet have a disposal problem given the low population density in the village. It is also not yet known whether the vermicompost can be stored for long periods of time and still maintain the nutrients and moisture retention capacity.
The way of life of the project beneficiaries lends itself easily to the principles of reuse, repair and recycle as the rural population already practices much reuse and recycling such as making sandals out of car tyres, consistent with the concept of the circular economy, which the project seeks to facilitate. From the discussions it emerged that there is a huge need for affordable organic insecticides, for example, and the group is planning to explore the idea of making insecticides from chili pepper.
Following initial experimentation and discussions a relatively straightforward and easy to understand and managed process of vermicomposting was adopted using mainly banana trees and the African Night Crawler specie of earthworms. This process was successfully carried out by the farming group and the vermicompost was produced and some of it applied to the second maize crop in 2018, with the results discussed above. Further research and experimentation is needed to address the challenges that are likely to arise from replication and scaling up to other communities such as education and sensitisation of the beneficiary population, availability and transportation costs for the organic materials and the finished product and handling and storage of the product when it is not used immediately.
The introduction of the simple technology has raised the morale and confidence of the community and has facilitated the exploration of other related potential circular economy interventions that can enhance adaptation, resilience and sustainability. The potential of chilli peppers to be processed into insecticides as is done in other countries is being considered. There is also the prospect for some community members specialising in rearing earthworms, growing or collecting the organic materials such as banana trees and providing handling and transportation services. Further research is also needed to determine the nutrient composition of the vermicompost produced in order to label the product accurately, whether the product can be stored for long and the optimal location of the vermicomposting sites given that periurban locations may provide easy access to household waste and contribute to solving the pollution problems of urban areas while providing a much needed product.