Climate-smart soil water and nutrient management options in semiarid West Africa: a review of evidence and analysis of stone bunds and zaï techniques

Abstract

There is an increasing need for West African Sahel farmers to be availed with appropriate technologies and management practices that sustainably increase productivity and resilience, while reducing greenhouse gas emissions where possible. In this paper, we analysed prevailing key water and nutrient interaction practices namely stone bund, zaï and half-moon techniques in order to explore how their outcomes could be linked to climate change adaptation and mitigation. Data were derived from previous publications but were reinterpreted in the angle of technologies' alignment with the three pillars of climate-smart agriculture (CSA). We found that the most successful systems are those that provide water, nutrients and a supportive soil structure in a synergistic manner. Indeed, technologies such as zaï, half-moons and stone bunds, combined with an application of organic/inorganic sources of nutrients, are promising climate-smart agricultural practices that could be widely used by smallholder farmers to maintain food production and secure farmers' livelihoods, while contributing to ecosystem services. However, accompanying incentive measures are needed to empower and capacitate rural farmers to adopt the considered techniques. These are successful examples that can form the basis for informing farmers and agricultural extensionists, as well as future agricultural development plans, policies and investments that pursue sustainable food and nutritional security in the West African Sahel.

Optimizing yield of improved varieties of millet and sorghum under highly variable rainfall conditions using contour ridges in Cinzana, Mali

“…Because of unpredictable rainfall [18] and decreased agricultural productivity, many soil and water conservation technologies such as stone lines, half-moons, contour hedgerows, rock bunds, filter walls, zaï, agroforestry, contour ridges, benches and no-tillage have been developed and are now widespread [19][20][21][22][23]. Tested technologies have shown that they can reduce runoff [16,[24][25][26] and soil erosion [27][28][29], improve water infiltration [12,22,30] and increase soil moisture [20,23,[31][32][33]. However, their adoption did not always meet the expectations probably due to the promotion of a limited number of options everywhere as if "one size fits all. "…”

Editorial for the Thematic Series in Agriculture & Food Security: Climate-Smart Agriculture Technologies in West Africa: learning from the ground AR4D experiences

“…As there are huge variations between geographic locations and socio-economic conditions in terms of risks to be faced and capacities to face them, CSA thrives to engage context-specific and locally adapted actions and interventions, along the whole agricultural value chain [7]. In the same line, it is believed that the management of natural and human resources of agricultural production at the very local level determines the success or failure in closing the yield gap [14].…”

“…In the region, although soil fertility is known as one of the major challenges faced by agriculture [5,6], climate change and variability add extra burdens [4]. Indeed, the livelihoods of people in the region depend on rain-fed agriculture and livestock [7], which are known to be the most vulnerable to climate change [8,9] with serious threats to food security.…”

Shallow wells, the untapped resource with a potential to improve agriculture and food security in southern Mali

“…Zougmoré et al [25] argued that loss of water through run-off, soil evaporation and drainage below the root zone account for the water deficiency (longer periods of water stress). This water, however, if managed properly could easily be used to recharge shallow wells to enhance the groundwater storage.…”

“…The commonly applied field level technologies include live fencing and grass strips [11], compost with mineral fertilizers [19,20], zaï or pit planting with organic amendments [21,22], stone and contour bunding [23,24], halfmoon techniques [21,25] and gully interventions [11]. However, these methods were piecemeal efforts that did not evolve into precise and efficient soil degradation control measures as they are labour-intensive and, with the increasing annual levels of degradation, only translated into marginal yield increase that is not sustainable [26].…”