Given that 70% of the African population is supposedly dependent on agriculture to sustain their livelihoods, it would seem that the African terrain is well suited for growing various crops. However, my previous blogs highlight that the potential for farming varies spatially – and this must mean that the difficulties and sustainability of farming must also vary amongst the 70% who are part of the agricultural sector. Nevertheless, families that have been farming have been doing so for generations, and traditional agricultural methods have been developed overtime to overcome and adapt to the obstacles and challenges presented by the African landscape. However, with climate change and changing water availability patterns, are these traditional methods adequate to withstand the pressures of the future, which include extreme flood and drought events? It is predicted that a 2 degree rise in the average global temperature could result in rainfall declining by up to 25% in many semi-arid regions (Schewe et al. 2013). Furthermore, in less than just 4 years time, 75 – 250 million people are predicted to suffer from water stress (AMCEN Secretariat). By 2020, rain-fed agriculture yields could be halved. These figures are not only worrying, but also highlight the urgency for farmers to change their practices. Do farmers have enough knowledge of basic water monitoring and management in order to adapt to the changes that are being predicted? We need to understand how farmers are currently addressing the situation.
Research also shows that 50-70% of the rainfall does not reach crops and instead either evaporates, or becomes run off (Rockstrom and Falkenmark 2015). My previous blog post touched upon conservation agriculture and the role of mulching as a solution to this. I want to now focus on techniques that are less technical in terms of the equipment needed (unlike irrigation or mulching), but are still very effective in terms of water efficiency. This leads me to draw attention to a successful water-harvesting example which is the Faanya-ju terraces in the Machakos district of Kenya. Terrace cultivation involves creating graduated terraces on natural slopes such as hills or mountains and planting crops on these steps (Encyclopaedia Britannica 2015).
Faanya-ju terraces are created by placing soil from trenches up slope to form bunds (banks) along a contour and repeating this process further upslope along more contour lines. Gradual erosion and redistribution of the soil eventually forms the terraces, as shown in Figure 1. Distance between each bund varies, however, they are generally 5-20 metres apart (UNEP). The unique spatial structure of the terraces including the bunds has the ability to control and direct water run-off where it is needed, so that water can be conserved within the soil, preventing dispersal and hence valuable water losses (Figure 2). This is where Faanya-ju got its name; it is the Kiswahili words for ‘throw it [soil] upwards’ (WOCAT 2016).
Figure 1: The development of the terraces overtime (Source)
Figure 2: Diagram to show how the terraces store water (Source)
In the Machakos District, 1000 km of new Faanya-ju terraces have been constructed each year since the 1980s. The National Soil Conservation Programme in Kenya trained over 500,000 farmers in conservation technologies, including faanya-ju farming. Now, 70% of the area practice terraced farming voluntarily, suggesting that there has been little or no resistance to this method by farmers (WOCAT 2016). Crop yields as a result of faanya-ju farming has reported to have increased by 50% which is a clear benefit to the farmers (UNEP). All this is evidence to support that the technique has generally been a success. Furthermore, beyond its obvious benefit to crop yields, stone terrace walls allow excess water to infiltrate between the stones and be redirected into nearby streams, improving the village water supply. The terraces have generally improved soil moisture and reduced erosion.
During the 2009 drought in the region, farms using faanya-ju terracing still yielded crops despite a lack of water (IIED). With droughts predicted to increase, there is a sense of hope that this can be a viable method that can be used in the future to withstand droughts. Nonetheless, the disadvantages of this method also need to be acknowledged. Faanya-ju farming can only be applied in very specific environments (Figure 3), such as where there are slopes, where annual rainfall exceeds 700 mm and where the soils are deep, meaning that it cannot be used as a method in the drier and flatter regions of Africa. The process is also very labour intensive and constant maintenance is required, especially if the bunds have not been stabilised and are prone to erosion (UNEP). Terracing also reduces the area available to plant crops on due to the presence of the bunds, however, it ensures greater yield security and decreases the chances of a crop failure. Despite the downfalls of the method, I think that the example goes to show that water-harvesting methods devised for small-scale farmers can be very successful and implemented on a mass scale if it is carefully thought out and farmers can easily realise the benefits. However, before applying the technique elsewhere, more research needs to be done on suitability of the sites before implementing this type of farming. Needless to say, areas outside of the district have recognised the positive impacts that it is having on crop yields and water harvesting and are slowly adapting the practices to suit their terrains. Rockstrom and Falkenmark (2000) claim that water harvesting can raise crop yields and productivity from 1 tonne per hectare to 3-4 tonnes per hectare. If there are landscapes similar to the Machakos district of Kenya elsewhere in Africa, then this is a technique that should definitely be promoted further. This is proof that traditional water-harvesting methods can go a long way and complicated technologies aren't always needed!
Figure 3: The environmental conditions that are optimal for Faanya-ju terracing (Source)
Here is a good supplementary video that documents the reality of Faanya-ju terracing well and the positive impact that it has had on farmers in the region:
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