Agriculture In West Africa Research Articles

Remote Sensing and Field Data Analysis to Evaluate the Impact of Stone Bunds on Rainfed Agriculture in West Africa

This study evaluates the effectiveness of stone bunds in enhancing soil moisture, vegetation health, and crop yields in Ghana’s semi-arid Upper East Region, an important area for agricultural productivity in West Africa. In this region, agricultural practices are heavily impacted by erratic rainfall and poor soil moisture retention, threatening food security. Despite the known benefits of traditional soil conservation practices like stone bunds, their effectiveness in this context has not been fully quantified. Field and remote sensing data were used to evaluate the influence of stone bunds on soil moisture dynamics, vegetation growth, and crop yield. Experimental plots with and without stone bunds were monitored for climate, soil water infiltration, and soil moisture and analyzed using the NDVI from Sentinel-2 satellite imagery over two growing seasons under sorghum production (2022–2023). The results indicated that stone bunds enhanced soil moisture retention and increased infiltration rates. The NDVI analysis consistently revealed higher vegetation health and growth in the plots with stone bunds, particularly during critical growth periods. The intermediate results of the conducted experiment indicated that stone bunds increased sorghum yields by over 35% compared to the control plots. The substantial agronomic benefits of stone bunds as a soil and water conservation strategy were evident, improving soil water infiltration, water retention, vegetation health, and crop yields. The findings support the broader adoption of stone bunds in semi-arid regions to enhance agricultural productivity and resilience against climate variability. Further research is recommended to explore the long-term impacts and the integration of stone bunds with other sustainable farming practices to optimize rainfed agricultural outcomes.

Estimating and mitigating greenhouse gas emissions from agriculture in West Africa: does threshold matter?

Estimating and mitigating greenhouse gas emissions from agriculture in West Africa: does threshold matter?

Optimal Sowing Windows under Rainfall Variability in Rainfed Agriculture in West Africa

Climate change is exacerbating adverse impacts of water stress in rainfed agriculture. This paper seeks to identify safe sowing windows for smallholder farmers in the Sudanian region of West Africa (WA). We hypothesize that the traditional focus on the onset of the season to start sowing leads to crop losses in years of high rainfall intermittency. AquaCrop, an FAO crop model, is used to simulate the yield response of maize (Zea mays L.) to sowing dates ranging from the 1st of May to the 30th of November at 20 locations in WA. We find that sowing directly after the first rains carries a higher risk of water stress, hampering crop development due to insufficient buildup of soil water storage to overcome dry spells. Based on three years of data per station on average, we identify safe sowing windows across the Sudanian region that secure optimal yield in 97% of all cases. We find that delaying sowing to mid-June (savanna and western part of the region) and to July (semi-arid region) ensures optimal yields. Of the three commonly applied local onset approaches covered in our evaluation, only LO10mm (10 mm/day on four consecutive days) achieves a similar yield result. The advantage of the safe window approach is that it is accessible for smallholders, who in many cases do not have access to local rainfall information.

Spatiotemporal monsoon characteristics and maize yields in West Africa

To assess the vulnerability of rainfed agriculture in West Africa (WA) to climate change, a detailed understanding of the relationship between food crop yields and seasonal rainfall characteristics is required. The highly seasonal rainfall in the region is expected to change characteristics such as seasonal timing, duration, intensity, and intermittency. The food crop yield response to changes in these characteristics needs greater understanding. We follow a data-driven approach based on historical yield and climate data. Such an approach complements model-based approaches. Previous data-driven studies use spatially and temporally averaged precipitation measures, which do not describe the high degree of spatial and temporal variability of the West African Monsoon (WAM), the primary source of water for agriculture in the region. This has led previous studies to find small or insignificant dependence of crop yields on precipitation amount. Here, we develop metrics that characterize important temporal features and variability in growing season precipitation, including total precipitation, onset and duration of the WAM, and number of non-precipitating days. For each temporal precipitation metric, we apply several unique spatial aggregation functions that allow us to assess how different patterns of high-resolution spatial variability are related to country-level maize yields. We develop correlation analyses between spatiotemporal precipitation metrics and detrended country-level maize yields based on findings that non-climatic factors, such as agricultural policy reform and increased investment, have driven the region’s long-term increase in maize yields. Results show that that the variability in the number of days without rain during the monsoon season and the lower bounds to the spatial rain pattern and end to the monsoon season are most strongly associated with maize yields. Our findings highlight the importance of considering spatial and temporal variability in precipitation when evaluating impacts on crop yields, providing a possible explanation for weak connections found in previous studies.

Climate Change Impact and Variability on Cereal Productivity among Smallholder Farmers under Future Production Systems in West Africa

Agriculture in West Africa is constrained by several yield-limiting factors, such as poor soil fertility, erratic rainfall distributions and low input systems. Projected changes in climate, thus, pose a threat since crop production is mainly rain-fed. The impact of climate change and its variation on the productivity of cereals in smallholder settings under future production systems in Navrongo, Ghana and Nioro du Rip, Senegal was assessed in this study. Data on management practices obtained from household surveys and projected agricultural development pathways (through stakeholder engagements), soil data, weather data (historical: 1980–2009 and five General Circulation Models; mid-century time slice 2040–2069 for two Representative Concentration Pathways; 4.5 and 8.5) were used for the impact assessment, employing a crop simulation model. Ensemble maize yield changes under the sustainable agricultural development pathway (SDP) were −13 and −16%, while under the unsustainable development pathway (USDP), yield changes were −19 and −20% in Navrongo and Nioro du Rip, respectively. The impact on sorghum and millet were lower than that on maize. Variations in climate change impact among smallholders were high with relative standard deviations (RSD) of between 14% and 60% across the cereals with variability being higher under the USDP, except for millet. Agricultural production systems with higher intensification but with less emphasis on soil conservation (USDP) will be more negatively impacted by climate change compared to relatively sustainable ones (SDP).

Intensification of Sorghum Production in Flood Recession Agriculture in Yelimane, Western Mali

Flood recession farming is as an important supplement to rainfed agriculture in West Africa. Every year, large areas are flooded along riverbanks and temporary lakes. When water recedes from the flooded areas, farmers plant crops. This study describes the flood recession farming in the Yelimane district of Kayes region in Mali and assesses different ways to intensify the system. The use of external inputs in this system is minimal. Field experiments were undertaken over two years to test crop establishment methods, soil tillage, increasing plant density, use of organic and mineral fertilizer, and improved varieties. These technologies increased sorghum yield as compared to the control in the following descending order: Seed priming + fertilizer (77.1%), NPK + organic fertilizer (74%), seedling transplantation + micro fertilization (61.3%), improved varieties (49%), mounding (34%), and urea application (24.9%). The technology seed priming in combination with mineral fertilizers was promising because of the high yield and the low labor demand. Nitrogen fertilizer is needed in flood recession agriculture as the soils and the deposited sediments are low in nitrogen. Farmers’ choice of technology will depend on the yield level, net return per hectare, labor use, and access to inputs.

On-farm trials identify adaptive management options for rainfed agriculture in West Africa

Rainfed crop production is the primary means of food security and income generation for rural households in semi-arid West Africa, which contains a high level of agro-ecological and socio-economic heterogeneity. Official management recommendations currently focus on the use of purchased certified seed and inorganic fertilizers, but are based primarily on highly controlled on-station trials that do not capture this heterogeneity and complexity of production systems. This study established hundreds of on-farm research trials across Senegal and The Gambia to test the agronomic benefit of multiple integrated practices related to seeds, inorganic fertilizers, and locally available organic amendments. All management practice were found to reliably increase yield across both the heterogeneity of this region and the diversity of the partnering farmers, and multiple integrated practices had greater effect than the currently recommended “best” practice. These alternative practices therefore offer an immediate pragmatic replacement to the existing recommendations and demonstrate the research and extension value of supervised on-farm trials. These findings also suggest that agronomic recommendations should focus on multiple “better” options rather than singular “best” practices, and farmers encouraged to select among these options based on their individual knowledge, circumstances, and preferences.

Agriculture Development, Employment Generation and Poverty Reduction in West Africa

Background: The problem of poverty eradication has been limited to the Economic Community of West African States (ECOWAS) region, which accounts for more than 40% of the world's poor population. The majority of these people are rural farmers who depend solely on agriculture for livelihood. Agriculture in West Africa remains the largest means of employment in which more than 60% of the sub-region’s active labour force is involved. Objective: This study examined the potentials of agriculture to generate employment for the people, thereby reducing the level of poverty in West Africa. Methods: The Generalized Method of Moments (GMM) econometric technique was employed in this study for the panel data covering the period of 17 years (2000 to 2016). Results: Results from the study showed that agriculture provides the opportunity for the poor to increase their earnings to escape the poverty trap, whether the poor can seize these agricultural opportunities depends on their human capital development. Conclusion: The study, therefore, concluded that effective policies (e.g. social protection) should be formulated in the agricultural development plans that will prioritize sustainable land and water management, access to markets, and the food security. To achieve this, the use of modern methods should be encouraged through farm incentives to boost agricultural production and increase farmer’s income which is earned through the sale of agricultural commodities, and thus; in the long run, increase the revenue accruing to the government and reduce the rate of poverty.

Wastewater used for urban agriculture in West Africa as a reservoir for antibacterial resistance dissemination

State of art metagenomics were used to investigate the microbial population, antibiotic resistance genes and plasmids of medical interest in wastewater used for urban agriculture in Ouagadougou (Burkina Faso). Wastewater samples were collected from three canals near agricultural fields in three neighbourhoods. Assessment of microbial population diversity revealed different microbial patterns among the different samples. Sequencing reads from the wastewaters revealed different functional specializations of microbial communities, with the predominance of carbohydrates and proteins metabolism functions. Eleven pathogen-specific and 56 orthologous virulence factor genes were detected in the wastewater samples. These virulence factors are usually found in human pathogens that cause gastroenteritis and/or diarrhoea. A wide range of antibiotic resistance genes was identified; 81 are transmissible by mobile genetic elements. These included seven different extended spectrum β-lactamase genes encoding synthesis of four enzyme families, including two metallo-β-lactamases (blaAIM-1 and blaGES-21). Ten different incompatibility groups of Enterobacteriaceae plasmid replicons (ColE, FIB, FIC, FII, P, Q, R, U, Y, and A/C), and 30 plasmid replicon types from Gram-positive bacteria. All are implicated in the wide distribution of antibiotic resistance genes. We conclude that wastewater used for urban agriculture in the city represents a high risk for spreading bacteria and antimicrobial resistance among humans and animals.

Toward climate-smart agriculture in West Africa: a review of climate change impacts, adaptation strategies and policy developments for the livestock, fishery and crop production sectors

Many projections of the impact of climate change on the crop, livestock and fishery production sectors of African agriculture are reported in the literature. However, they may be arguably too general to understand the magnitude of impact and to inform adaptation strategies and policy development efforts that are tailored to promoting climate-smart agriculture in the West African region alone. This paper was synthesized from several scholarly literature and aimed at providing up-to-date information on climate change impacts, adaptation strategies, policies and institutional mechanisms that each agriculture subsector had put in place in dealing with climate change and its related issues in West Africa. For each subsector (crop, fishery and livestock), the current status, climate change impacts, mitigation and adaption strategies have been analyzed. In addition, we reviewed recent policy initiatives in the region that foster the development and adoption of climate-smart agricultural options to improve resilience of farming systems and livelihoods of smallholder farmers to climate change risks. From community to national and regional levels, various strategies and policies are also being taken to guide actions and investment for climate-smart agriculture in West Africa.

Agriculture in West Africa in the Twenty-First Century: Climate Change and Impacts Scenarios, and Potential for Adaptation.

West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture, and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature. West Africa is nowadays experiencing a rapid climate change, characterized by a widespread warming, a recovery of the monsoonal precipitation, and an increase in the occurrence of climate extremes. The observed climate tendencies are also projected to continue in the twenty-first century under moderate and high emission scenarios, although large uncertainties still affect simulations of the future West African climate, especially regarding the summer precipitation. However, despite diverging future projections of the monsoonal rainfall, which is essential for rain-fed agriculture, a robust evidence of yield loss in West Africa emerges. This yield loss is mainly driven by increased mean temperature while potential wetter or drier conditions as well as elevated CO2 concentrations can modulate this effect. Potential for adaptation is illustrated for major crops in West Africa through a selection of studies based on process-based crop models to adjust cropping systems (change in varieties, sowing dates and density, irrigation, fertilizer management) to future climate. Results of the cited studies are crop and region specific and no clear conclusions can be made regarding the most effective adaptation options. Further efforts are needed to improve modeling of the monsoon system and to better quantify the uncertainty in its changes under a warmer climate, in the response of the crops to such changes and in the potential for adaptation.

Chromolaena odorata (L.) R.M. King & H. Rob. (Asteraceae) in sub-Saharan Africa: A synthesis and review of its medicinal potential

Ethnopharmacological relevanceChromolaena odorata (L.) R.M. King & H. Rob. (Asteraceae) is a scrambling perennial shrub that originated in the Americas, but is now common in sub-Saharan Africa, Asia and Oceania, where it has become a serious weed. The species, particularly the biotype found in Asia and West Africa, has many ethnopharmacological uses, including treatment of malaria, wounds, diarrhoea, skin infection, toothache, dysentery, stomach ache, sore throat, convulsions, piles, coughs and colds. Furthermore, no attempt has been made to synthesise and review the available literature on the usefulness of the plant in the sub-Saharan African region, hence this paper examines the beneficial attributes of C. odorata in sub-Saharan Africa. Material and methodsPublished information on the species was gathered by the use of different database platforms, including Google Scholar, ScienceDirect, SciFinder and Scopus. ResultsRecords indicate that two biotypes of C. odorata are present in sub-Saharan Africa viz. the more widespread Asian/West African C. odorata biotype (AWAB) and the southern African biotype (SAB). While the usefulness of the former is well elucidated in the literature, such information on the latter is still scarce. Although the importance of AWAB C. odorata as a fallow species and as a soil fertility improvement plant in the slash and burn rotation system of agriculture in West Africa is increasingly being recognised, its usage in traditional medicinal practice is far more appreciated. The species has a wide range of ethnopharmacological uses, possibly because of the presence of flavonoids, essential oils, phenolics, tannins and saponins. The plant is reported to have antibacterial, anti-inflammatory, antioxidant, anthelminthic, antifungal, cytotoxic, anticonvulsant, antiprotozoal, antispasmodic, antipyretic and analgesic properties. ConclusionWhile the results of this review suggest that the AWAB plant can be exploited as an alternative to other threatened plant species known to possess similar medicinal potential, the medicinal and pharmacological potential of the SAB plant remains to be established. Further studies on the phytochemistry and pharmacological properties of the SAB plants will not only advance our knowledge of ethnobotany and ethnomedicine, but may also improve the health and knowledge of the local people.

A question of timing: spatio-temporal structure and mechanisms of early agriculture expansion in West Africa

Although understanding the emergence of agriculture in West Africa has recently benefited from major advances, the reasons for its fast diffusion south of the Sahara remain to be explained. We propose here a reconstruction of African agriculture expansion built from a spatialization of available archaeological data and associated radiocarbon dates. With this approach, we can show that the initial spread of food production occurred with some specific rhythms. From this structure, we discuss the potential underlying processes. Our work suggests that the spread of agriculture in West Africa cannot be explained by a simple response to an abrupt environmental change at the beginning of the Late Holocene, but rather by a combined climate-culture mechanism. In addition, cord-wrapped roulette-impressed pottery appears to be a good indicator of the expansion of agro-pastoralist populations in Sub-Saharan regions. Our results are also consistent with the assumption of a monophyletic origin of domestic pearl millet in south-western Sahara and strengthen the idea that the first cultivators were Saharan pastoralists.

Unravelling institutional determinants affecting change in agriculture in West Africa

This paper compares lessons learned from nine studies that explored institutional determinants of innovation towards sustainable intensification of West African agriculture. The studies investigated issues relating to crop, animal, and resources management in Benin, Ghana, and Mali. The constraints addressed were agronomic or economic (e.g. low production, yield, quality, prices) and institutional (e.g. poor access to resources and constraining regulations) and were analysed using an array of research approaches. The studies showed that political ambitions to foster institutional change were often high (restoring the Beninese cotton sector and protecting Ghanaian farmers against fluctuating cocoa prices) and that the institutional change achieved was often remarkable. However, flexibility of institutions, co-evolution of technical and institutional change, and increased transparency are needed to make institutional change successful. The programme Convergence of Sciences – Strengthening Agricultural Innovation Systems encouraged interventions where needed and enabled researchers and stakeholders to acquire the change capacities required to identify the need and potential for change and to make change happen. More research is needed to design pathways towards sustainable intensification based on social and technological innovation. Policy-makers should create space for institutional experimentation and empower smallholder farmers in West Africa to create resilient, local food systems to feed burgeoning urban populations.

Institutional change towards sustainable agriculture in West Africa

This paper describes why inter- and trans-disciplinary research, accompanied by innovation platforms, is essential in the context of agricultural development in West Africa. The institutional context in West Africa can become a trap for smallholder farmers and for society at large. Therefore, we argue that an enabling institutional context is necessary to achieve an increase in agricultural production. This will have consequences for setting priorities of agricultural research and the way research should be organized in order to have impact. Within the framework of two consecutive programmes, attempts were made to create such an enabling context. The first programme, focusing on participatory technology development, showed that smallholders can capture only limited benefits from technologies because of their constrained opportunities. The point of departure for the second programme was that institutions explain a large portion of variance in agricultural output and that multi-stakeholder innovation platforms at local, district, and national levels are needed to create change. The paper concludes with an overview of this special issue, which provides nine case studies of institutional factors that influence smallholder innovation. Each of these case studies identifies and analyses institutional mechanisms at aggregation levels higher than the household, farm, or village.

A framework for the use of decision-support tools at various spatial scales for the management of irrigated agriculture in West-Africa

The Kou watershed, situated in the Southwestern part of Burkina Faso, has succumbed since a couple of decades in a typical theater play of anarchistic water management. With its 1800 km2, this small watershed holds the second largest city of Burkina Faso (Bobo-Dioulasso), a former State ran irrigated rice scheme and several informal agricultural zones. Despite the abundance on water resources, most water users find themselves regularly facing to water shortages due to an increase in population and low irrigation efficiencies. Local stakeholders are hence in need of easy-to-use and low-cost decision support tools for the monitoring and exploitation of the water resources at different spatial and user levels. A top-to-bottom string of adapted water management tools has been successfully installed to tackle the problems: from watershed (top) to field level (bottom), passing by the 1200 ha irrigation scheme. Land use maps have been derived from time-series of free satellite images. Combined with data from a network of hydrologic gauging stations, regional water use maps were established. SIMIS was put in place for the public-private management of the regions irrigated rice scheme. Day to day water use on irrigated plots was followed by soil humidity and crop canopy measurements. A simple field-cropwater balance model Aqua Crop was used by extension workers to draft optimal irrigation charts. Each tool was applied independently, requiring only limited data; but their combined results contributed to an improved integrated water management.

Pratylenchus speijeri n. sp. (Nematoda: Pratylenchidae), a new root-lesion nematode pest of plantain in West Africa

A new root-lesion nematode, particularly pathogenic to Musa spp. and causing important plantain losses in Ghana, is described and named Pratylenchus speijeri n. sp. The cryptic status of this species within the P. coffeae species complex has been assessed and confirmed in this study. An extensive comparison of the morphological and molecular characteristics of this new species with those of P. coffeae and other related amphimictic species did not result in an unambiguous separation of this species from P. coffeae because only a few morphological features of diagnostic value were found. Sequence and phylogenetic analyses of the D2-D3 expansion segments of the 28S rRNA gene, the ITS rRNA gene and a portion of the hsp90 gene of P. speijeri n. sp. and P. coffeae species complex populations from different sources generated majority consensus BI trees with three major clades: P. speijeri n. sp. from Musa spp. roots in Ghana; unidentified or putative new Pratylenchus sp. C1 from Colocasia esculenta roots in Japan and P. coffeae with non-homogeneous relationships from different hosts and distant geographical areas. These results confirmed the validity of P. speijeri n. sp. as a new taxon and indicated that P. coffeae populations from Colocasia in Japan also need to be considered as a new species. Sequence differences in the ITS were used to design group- and species-specific primers to detect P. speijeri n. sp. and other species of P. coffeae species complex. The use of these species-specific primers for the separation of P. speijeri n. sp., Pratylenchus sp. C1 and P. coffeae has important practical application in breeding programmes for agriculture in West Africa.

Cross-Location Analysis of the Impact of Household Socioeconomic Status on Participation in Urban and Peri-Urban Agriculture in West Africa

This study explores the relation between household socioeconomic status (SES) and participation in urban and periurban agriculture (UPA) in three West African cities. We used a structured questionnaire to survey 700 randomly selected households: 250 in Kano, Nigeria, 250 in Bobo Dioulasso, Burkina Faso, and 200 in Sikasso, Mali. Multiple correspondence analysis was applied on household asset variables to create an index of assets which was used as a proxy for household SES. The results showed no significant differences in households’ rate of participation in UPA across socioeconomic groups. Participation in UPA was rather significantly (P < 0.001) and positively related to household size. Interestingly, the analysis revealed that field crop cultivation and gardening were more common among households in the low and medium SES groups while those in the high SES group were more likely to keep livestock.

A modeling assessment of geneflow in smallholder agriculture in West Africa

PurposeSmall-scale agriculture is an important issue for food security in Africa. In the context of Genetically Modified Organisms, approaches to quantify geneflow in small-scale systems are widely unexplored. We aimed at bridging this gap by contributing to the scientific discussion on the uncertainties of the cultivation of genetically modified (GM) crops in the region. The safety issue is: Would it be possible to withdraw a variety in case that unexpected and undesirable effects occur? e.g. the resistance of pests which make the variety no more useful.MethodsWe used a GIS approach to determine the location of maize cultivation sites, field geometries and applied a model for the calculation of geneflow scenarios.ResultsThe data revealed that the given cropping density provides optimal conditions for transgene spread, potentially limiting the possibility for coexistence between GM and non-GM fields. On average, we found about 60 fields within a nearest distance of 100 m, and cropping density of 56 fields per square kilometer. The resulting cross-pollination rate from the single GM field into the neighbouring conventional fields was estimated to be about 0.12%.ConclusionsGM varieties if introduced could remain in cultivation even if their admission has expired or has been retracted. This would be undesirable and could cause long-term, undesirable stacked combination of transgenes which cannot be tested with respect to eventual combinatory effects. These developments pose major challenges for fielder livelihoods, and conservation of maize genetic resources with potentially negative consequences for the African food export sector.

Besieged Palaeonegritics or Innovative Farmers: Historical Political Ecology of Intensive and Terraced Agriculture in West Africa and Sudan

This article provides an overview of the historical occurrences of terracing, manuring and other features of intensive agriculture in West Africa and Sudan. The aim is to shed more general light on the political, economic and social contexts of precolonial intensive farming in sub-Saharan Africa. The article uses the vantage point of recent debates on driving forces behind terracing and irrigation in East Africa. It argues that despite being regularly cited as fact in the literature on terraced agriculture on West Africa, no clear historical evidence is available to show that slave raiding was indeed the determining factor behind the first settlement of these hills and the terracing. The farming systems of the late precolonial period must definitely be seen as an outcome of the political economy of the slave trade period. But the idea that the intensification is the outcome of the retreat of decentralised societies into hills and mountains is challenged by the fact that intensification also occurred on the plains and in areas dominated by stratified social organisation and predatory states. It seems as if the labour mobilisation required for intensive agriculture was achieved at both ends of this social continuum. Conflicts and defensive strategies, as well as cooperation in the forms of intermarriage, trade, etc, formed part of a long-term process of different groups relating to one another, intensifying their agriculture and developing a geographical division of labour.