What’s the issue?
African smallholder farmers are facing a widespread existential crisis linked to the degraded state of their soils. Across densely settled, rainfed farming areas, productivity is low because the carbon-depleted soils do not accept or hold onto water or nutrients well. These degraded soils, in turn, put farmers at greater risk from increasingly erratic and extreme climate events.
How can this issue be addressed?
Soil functional characteristics and soil health more generally can be improved by increasing soil carbon levels. The regular addition of plant and animal residues restores multiple soil functions and confers greater resilience to environmental stresses such as drought or flooding. However, farmers cannot simply be told to increase organic matter in their soils. Many farmers are unaware of the critical roles that soil carbon plays in a healthy soil. Moreover, their soils are often too degraded to generate residues without significant change in management practice. Our current approach centers on incremental learning and discovery by the farmers themselves about soil carbon and how to restore and maintain it.
Soil tests allow farmers to see how carbon influences soil health
The learning and discovery begin with soil tests that farmers can do on their own soils.
At a soil health workshop in Kitale in 2019, farmers brought soil samples of their best and worst soils from their own farms. They were able to see clear visual differences in the amount of readily mineralizable carbon (particulate organic matter) recovered from the two soil types.
Photo by S.Vanek
Through analysis of soil samples collected from sites around the workshop venue that were subjected to different management strategies, farmers saw that soils with high carbon levels also had
- greater abundance and diversity of soil organisms (which contribute to suppression of detrimental soil organisms and enhanced nutrient cycling)
- better infiltration of water
- increased resistance to erosion
These practical experiences stimulated farmers’ appreciation of how carbon affects soil functioning. The farmers were also motivated to experiment with several management practices to determine if their use increases soil carbon levels and thus soil health.
The practices of interest identified from the workshop were use of
- biochar (charcoal made from carpentry waste and other high carbon residues)
- boma compost (compost made from high carbon residues laid down as bedding in livestock corrals to soak up the nutrient rich urine and mix together with the livestock dung)
- lablab green manure (Lablab is a high-biomass-producing, N-fixing legume from which edible grain and leaves can be harvested prior to incorporation of its residues.)
All of these options have good potential for increasing the amount of carbon that farmers are currently adding to their soils.
Sharing the learning, experimenting on farms
The farmers and extension agents who attended the initial soil health workshop are serving as the nucleus for bringing other farmers on board, using the same experiential learning approach we used at the workshop.
The organizations working with experimenting farmers have agreed to share their experiences using this same learning approach.
The Anchor Hub is supporting this effort by providing relevant information and protocols on this website. It is also providing modest resources to facilitate farmer-to-farmer sharing about their experiences with carbon-enhancing interventions on their farms.