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Birhanu and Tabo Agric & Food Secur (2016) 5:5 DOI 10.1186/s40066-016-0054-8 Agriculture & Food Security RESEARCH Open Access Shallow wells, the untapped resource with a potential to improve agriculture and food security in southern Mali Birhanu Zemadim Birhanu* and Ramadjita Tabo Abstract Background: Excessive rainwater during the rainy season and lack of water in the dry season have been challenging the agricultural productivity and food security for rural communities in southern Mali. Various soil and water conserva- tion practices were implemented in the past to improve crop yields and income, and reverse the effect of land degra- dation. However, none of these efforts looked into the potential use of shallow wells at a spatial scale to improve the agricultural productivity and hence the food security in the region. Results: In total 484 shallow wells were geo-referenced, mapped and studied in two districts, Bougouni and Koutiala, in southern Mali to understand the dynamics of groundwater recharge and relationship with rainfall in different sea- sons. The study found out that shallow wells were mainly utilized for household and livestock water consumption and not for agricultural water use. Well construction history followed the trend of the severe drought that hit the Sahel in the years of the 1970s and 1980s. Majority of wells (87 % in Bougouni and 84 % in Koutiala) were constructed after the drought period with significant variation of construction in the two districts (p value 0.032). Well depths ranged from 1 to 150 m, with the majority of wells (64 %) within the depth range of 6.5–14.5 m (p value 0.043). During the dry season water was available in the majority of wells (73 %) at a depth range from 5.5 to 15.5 m (p value 0.996). In the rainy season on average 84 % of wells in Bougouni and 94 % of wells in Koutiala experience water level rise within the range of 0.5–10.5 m (p value 0.423/Bougouni and 0.991/Koutiala). In few of the studied villages shallow wells were found to be fast recharging, thus enabling farmers to buffer the negative effects of drought conditions. Conclusion: Shallow wells are important sources of water in rural Mali. The wells have adequate recharging capacity during the rainy season and insignificant water level variation during the dry season. Though accessing water from shallow wells was labour-intensive and mostly done by women and the youth, water is available within an average depth ranging from 5.5 to 15.5 m from most studied wells. The issue of water scarcity in different seasons was thus attributed to accessibility due to the lack of appropriate water lifting mechanisms. Groundwater was an untapped resource in Mali, and we suggest groundwater management needs to be given consideration along with other man- agement practices in the changing climate condition to improve the agricultural productivity and food security. Keywords: Agriculture and food security, Bougouni district, Geo-referencing and mapping, Groundwater, Koutiala district, Monitoring shallow wells, Southern Mali, Water level variation Background productivity in developing countries particularly those of Climate change, land degradation, population growth and rural communities of sub-Saharan Africa [1]. The soils of over reliance on rainfed agriculture are common social sub-Saharan Africa are inherently poor in fertility char- and biophysical constraints to increased agricultural acterized by low productivity, and in addition to nutrient scarcity, land degradation and water stress hamper con- *Correspondence: [email protected]; [email protected] siderably the agricultural development of the region [2]. International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), These daunting challenges constitute potential setbacks West and Central Africa Hub (WCA), Samanko, BP 320, Bamako, Mali © 2016 Birhanu and Tabo. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons. org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Birhanu and Tabo Agric & Food Secur (2016) 5:5 Page 2 of 13 for agricultural development efforts in many countries of shorter in many areas, which inevitably require a radi- sub-Saharan Africa including Mali. cal shift in farming and natural resource management Located in West Africa and land locked, Mali is one of practices. the least developed countries with an economy that relies Various soil and water management practices were heavily on rainfed agriculture and livestock [3]. Small- implemented by local communities with the main objec- holder agricultural production is dominated by rainfed tive of improving crop yields and reversing the effect of production of millet, sorghum and maize for meeting land degradation such as water erosion from farm fields. food demands and on cotton for the market. Agricultural The commonly applied field level technologies include production is inadequate to feed Mali’s population, which live fencing and grass strips [11], compost with mineral is growing at a rate of nearly 3 % per year and at present fertilizers [19, 20], zaï or pit planting with organic amend- over a quarter of Mali’s population is undernourished [4]. ments [21, 22], stone and contour bunding [23, 24], half- The Malian economy is based mainly on cotton export moon techniques [21, 25] and gully interventions [11]. which contributes 10 % of the national GDP and consti- However, these methods were piecemeal efforts that did tutes the main source of cash for 2.5 million of farmers not evolve into precise and efficient soil degradation con- in the southern part [5]. Challenges faced by farmers in trol measures as they are labour-intensive and, with the Mali particularly in the southern part include among increasing annual levels of degradation, only translated others, excessive rainwater during the rainy season, scar- into marginal yield increase that is not sustainable [26]. city of water in the dry season, soil acidity and nutrient A report by Jalloh et al. [27] highlighted that significant depletion [6], rapid land degradation caused by decades decline in crop yields is expected until 2050 in West of intensive and extensive cotton cultivation [7], and high Africa Sahel if no further adaptation measures are taken. costs of fertilizers that contribute to low crop yields [8], Zougmoré et al. [25] argued that loss of water through consequently making poverty rampant [9]. It was also run-off, soil evaporation and drainage below the root recognized that yield gaps in the semi-arid regions of zone account for the water deficiency (longer periods of West Africa are results of inefficient land, water and crop water stress). This water, however, if managed properly management practices [10]. could easily be used to recharge shallow wells to enhance Soil erosion by wind and water and soil physical deg- the groundwater storage. Most efforts in the past focused radation, for example crust development, are important on land management practices with little attention to processes of soil degradation in southern Mali. During improve aquifer recharge. In southern Mali in particular the droughts of the 1970s and 1980s, bare soils were vul- there were few studies that looked into the potential use nerable to wind erosion, and large areas lost most of their of shallow wells to store the excess rainwater and sup- top soils. Winds transported the eroded soils (dust) and plement water shortages in different seasons to improve deposited them elsewhere forming new layers of topsoil food security. Groundwater provides a reliable, high up to a decimetre thick. Substantial water run-off and quality and accessible sources of fresh water that enables soil erosion usually occur on these soils when surface farmers to militate against the production risks associ- run-off is high [11], and this erosion is often observed in ated with extreme weather events and climate variability areas with compacted soils having low water infiltration [28]. The current study was conducted to understand the capacity. Thus, run-off and wind contribute to soil deg- recharging capacities of existing shallow wells in differ- radation through erosion of the upper layers which ulti- ent seasons as a potential groundwater source to improve mately reduce water availability for crops and trees of the the current agricultural productivity and incomes (food parkland [12]. security) in southern Mali. Using 484 shallow wells spa- In southern Mali, the estimated water run-off was at tially spread in ten farming communities, we tested and 20–40 % of annual rainfall and up to 70 % of individual presented availability of water for various purposes in dif- rainstorms [13]. Soil losses in cultivated soils were 25 kg ferent seasons. of N ha−1 year−1 and 20 kg of K ha−1 year−1. The conclu- sion was that 44 % of the losses in farmers’ incomes were Methods due to soil depletion [14]. Southern Mali receives mean Site characteristics annual rainfall ranging from 500 to 1000 mm with strong The study was conducted in ten farming communities variations and irregular rainfall events most of the times located in the two districts of Sikasso region in southern [15]. Water scarcity associated with rainfall variability Mali (Fig. 1). In Bougouni district, the target communi- poses one of the biggest obstacles to the achievement of ties were Dieba, Flola, Madina, Sibirila and Yorobou- food security and poverty reduction in the region. Recent goula. Similarly, the five target communities in Koutiala reports [16–18] indicated that in West African countries district were M’Pessoba, Nampossela, N’Golonianasso, rainfall has become less reliable and growing seasons are Sirakele and Zanzoni.

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