Sahelian Zone Research Articles

Experimentation of a better methanogenic potential by co-digestion of urban waste: Contribution to the challenges of sustainable development in the Sahel zone

Experimentation of a better methanogenic potential by co-digestion of urban waste: Contribution to the challenges of sustainable development in the Sahel zone

New multivariate models for the estimation of earth’s albedo and its variation with meteorological parameters over Kano, Nigeria

The study of what happens to sunlight as it goes through the atmosphere is vital to many fields of science because over time, reflection, scattering, and absorption in the atmosphere have changed the amount of solar radiation that reaches the Earth's surface. This study examined the variation in albedo over Kano, situated in the Sahelian climatic zone of Nigeria. The study's data, which covered the years 1984–2022, totaled thirty-nine, was obtained from the National Aeronautics and Space Administration (NASA). Utilizing monthly average daily measured meteorological data on global solar radiation, wind speed, mean temperature, surface pressure, and relative humidity, eleven models of three categories based on two, three, and four variable regression models were developed. Five validation indicators were used to verify the regression models: the t-test, coefficient of determination (R2), mean percentage error (MPE), root mean square error (RMSE), and mean bias error (MBE). The developed models that were considered most appropriate for estimating surface albedo were ranked; the three-variable regression model ALB7, which included the wind speed, relative humidity, and mean temperature, outperformed the previously employed generalized method from literature in estimating surface albedo over Kano. The variation of measured albedo with meteorological parameters depicts a direct relationship for clearness index and wind speed; an inverse relationship was observed for surface pressure. Mean temperature and surface pressure exhibit an inverse relationship during the wet season and vice versa for the dry season.

Origin and distribution of clay minerals in semi-arid Sahelian soils: case of Kori Ouallam watershed, south-western Niger

Abstract This study examines the origin and distribution of clay minerals of the pedological horizons of Kori Ouallam watershed (south-western Niger). It is based on field sampling campaigns and a series of laboratory analyses. A total of 49 samples were analysed, 28 from surface horizons (0–10 cm depth) and 21 from pedological profiles (0–1 m depth). The samples were analysed by X-ray diffraction on bulk and clay (<2 μm) fractions, X-ray fluorescence spectrometry, laser granulometry, organic matter and calcium carbonate content, macroscopic observations (binocular loupe) and scanning electron microscopy equipped with an energy-dispersive spectrometry system. The pedological horizons are characterized by low organic matter contents (<1%) and no calcium carbonate. The particle-size distribution shows net textural differentiation, with a predominance of sandy loam to sandy clay loam textures in the upper horizons and clay loam to clay in the deep horizons. The main major oxides were SiO2 (46.3–89.0%), Al2O3 (5.0–24.2%) and Fe2O3 (1.0–27.9%). Kaolinite (64–98%) is the predominant clay mineral at all horizons, associated with low to moderate proportions of illite (1–34%) and traces of chlorite. Kaolinite is essentially inherited from the parent rock, whereas illite results from chemical alteration by bisialitization of the primary minerals initially rich in potassium feldspar contained in the parent rock. However, soil texture and organic matter vary independently with clay mineralogy. An extended study of all of the pedological facies that make up south-western Niger, combined with supplementary analyses, would further improve our understanding of clay mineralogy in the Sahelian zone.

Morphological adaptation to environmental stress in small ruminants from the sahelian zones of Niger and potential associations with carcass yield

This study analyses, in the Sahelian zone of Niger, the morphological traits of sheep and goats' responses to environmental stress and the contribution of adaptive traits to herd productivity. The study utilized 2490 adult small ruminants, including 653 red and Sahelian goats and 1837 Peulh (with three varieties: Balami, Oudah and Bali-Bali) and Tuareg (Ara-ara) sheep from 13 sites with a marked aridity gradient within the country's northern latitude. Carcass yield was assessed on a second sample of 1617 adult animals, comprising 876 sheep and 741 goats. Variations in thorax auricular index (ratio of ear length to thorax depth), gracility index (which reflects the subtraction of the animal's body from the ground) and hot carcass yield, according to climate zones and breed, were subjected to an analysis of variance at the 5% risk threshold. Principal Component Analysis was used to analyze correlations between biometric and heat indices. For most breeds, the auricular thorax index and the gracility index were higher for animals in arid zones than those in humid zones. The increase in the average values of the body indices had as a result an increase in the animals' carcass yield and live weight. In all sheep and goat breeds, gracility increases with heat index. Gracility differed (p < 0.05) between breeds, with Bali-Bali and Oudah subgenetics of the Peulh sheep breed being more gracile than the Ara-ara sheep. Also, the auricular thorax index was higher (p < 0.05) in Sahelian goat than in red goat. The importance of biometric indices in terms of animals' adaptability to their environment means that we need to define important heat stress indicators specific to sheep and goats in Sahelian farming systems.

Urogenital schistosomiasis in schoolchildren in the lake zones of Kankossa and Oued Rawdha, southern Mauritania: The first parasitological and malacological survey.

Urogenital schistosomiasis due to Schistosoma haematobium is a major public health problem in Mauritania, but little is known about its epidemiology in many areas of the country, particularly in the lake zones. The objectives of the present parasitological and malacological study were to assess the prevalence and intensity of urogenital schistosomiasis among school children in Kankossa and Oued Rawdha lakes, southern Mauritania, and determine the species of intermediate host snails and the prevalence of snails with schistosome. A school-based epidemiological survey was conducted in two villages in the lake areas of Kankossa and Oued Rawdha. Urine samples were collected from 450 state primary school children and Koranic school children and examined for the presence of S. haematobium eggs using filtration technique. Water bodies adjacent to human settlement were surveyed for Bulinus and Biomphalaria snails that may potentially be intermediate hosts of S. haematobium. Morphological, molecular, and proteomic (i.e. matrix-assisted laser desorption ionization time-of-flight mass spectrometry [MALDI-TOF MS]) identification of collected snails were conducted, and their infection status was assessed by real-time polymerase chain reaction (RT-PCR) using the highly repetitive DraI gene. The prevalence of urogenital schistosomiasis was 35.6% and 15.8% in Kankossa and Oued Rawdha villages, respectively, corresponding to 'moderate' prevalence (i.e., 10-49% infected schoolchildren). Urogenital schistosomiasis prevalence was higher in boys (30.0%) than in girls (21.2%; P < 0.05), and in Koranic schools pupils (37.1%) than in state schools (20.5%; P < 0.05) pupils. Multiple regression analysis showed that sex (odds ratio [OR]: 1.64; 95% confidence interval [95% CI]: 1.06-2.57; P = 0.03) and Koranic school level (OR: 1.79; 95% CI: 1.06-3.04; P = 0.03) were independently and significantly associated with urogenital schistosomiasis. Based on molecular and proteomic identification, both B. senegalensis and B. umbilicatus colonized the water bodies of Oued Rawdha, whereas both B. forskalii and B. truncatus colonized those of Kankossa. The DraI RT-PCR detected S. haematobium complex DNA in 8 of 66 (12.1%) analysed snails: one B. truncatus and one B. forskalii in Kankossa and five B. senegalensis and one B. umbilicatus in Oued Rawdha. Urogenital schistosomiasis is moderately prevalent in the lake zones of Kankossa and, to a lesser extent, Oued Rawdha, located in southern Mauritania. Mass drug administration campaigns with praziquantel should be conducted to reduce the prevalence of urogenital schistosomiasis among school-aged children in the lake zone of Kankossa and Oued Rawdha village. Further parasitological and malacological studies should be conducted in other villages located in the Mauritanian lakes in the southern Sahelian zones and the northern oasis areas to strengthen our knowledge of the current epidemiological situation and implement appropriate urogenital schistosomiasis control strategies.

Agromorphological Characterization of the Main Sesame Varieties Grown in the Sahelian Zone of Chad

Sesame (&amp;lt;i&amp;gt;Sesamum indicum&amp;lt;/i&amp;gt; L.) would be one of the oldest cultivated plants in the world. Currently in Chad, its cultivation is in vogue and constitutes one of the priorities of farmers. The objective of this study was to highlight the agronomic and morphological characteristics of two varieties of sesame grown in the Sahelian zone of Chad. The experiment was conducted in open fields in the natural site of Kournari, around thirty kilometers from the capital N&amp;apos;Djamena. The local black seed and white seed S-42 varieties were grown in a randomized Fisher block design with 3 replicates. Plant height, number of leaves, number of capsules, number of seeds per capsule, average seed weight, weight of 1000 seeds, and grain yields per plant were determined. The measured parameters showed that vegetative development is greater in the S-42 variety than in the local variety. While in terms of yield per plant, the local variety is more productive with 33.01 g per plant compared to 20.08 g per plant for the S-42 variety. Plant height had a negative effect on grain yield per plant. It would be interesting to study the characteristics of other varieties in order to identify those which would best respond to the Sahelian climate.

Impact of climate, land management and harvesting patterns on the ecological traits and the population structure of Pterocarpus lucens in West African semi-arid areas

Multipurpose woody plant species experience severe pressure owing to human overexploitation, land management and climate change. In response to their inability to cope with environmental disturbances in their natural range, some species such as Pterocarpus lucens migrate to more suitable areas. To better conserve P. lucens, this study examined the impacts of climate, land management and harvesting practices on its natural populations.This study was conducted in Burkina Faso using a combined gradient approach involving two climatic zones and two land management types. Data on the biological age classes, structural traits and intensities of harvesting were collected on each individual of the species. Linear models were used to assess the effects of the investigated gradients on structural traits of the species. The diameter and height class size distributions were evaluated using the least squares method.The results showed that the species’ pre-reproductive individuals increased significantly (p < 0.05) with climatic and the protection gradient, resulting in an invasive trend of P. lucens in the Sudano-Sahelian protected areas. The species is overexploited in unprotected areas, with the majority of individuals undergoing all pruning intensities. However, while in the Sahelian climatic zone, decreasing pruning rates were observed according to the severity gradient (low intensity 36.02 %, moderate intensity 27.47 %, and severe intensity 19.73 %), an increasing pruning rate was observed in the Sudan-Sahelian climatic zone (low intensity 16.49 %, moderate intensity 17.38 %, severe intensity 24.48 %, and very severe intensity 35.79 %). Linear regression analysis showed a significant effect (p < 0.05) of climate, land management, pruning, and debarking on the structural traits of the species. The diameter class structure revealed unstable populations of the adult stratum in the Sahelian climatic zone, regardless of the land management types. The juvenile stratum of this species exhibited an unstable structure in unprotected areas, regardless of climatic zone.This study highlights the urgent need to implement effective management strategies to mitigate the decline of P. lucens populations in the Sahelian climatic zone and in unprotected areas through its integration in reforestation programmes.

Historical Analysis of Climate Variability and Agricultural Production in Nigeria (1931-2020)

This study investigates the historical dynamics of climate variability and its impacts on agricultural production in Nigeria from 1931 to 2020. Utilizing a robust analytical framework that integrates climatic data analysis, statistical modelling, and geographic information system (GIS) techniques, the research explores trends in temperature and precipitation across different agro-ecological zones. Key findings reveal a consistent upward trend in average annual temperatures, with more pronounced warming observed in northern Nigeria, notably the Sahelian zone. Concurrently, precipitation patterns exhibit regional disparities, characterized by increased rainfall in southern regions and variable patterns in the north, including periods of severe droughts during the 1970s and 1980s. Statistical analyses employing Mann-Kendall trend tests and regression models confirm significant temperature increases and varying precipitation trends, underscoring their direct impacts on agricultural productivity. The study highlights the sensitivity of crop yields to climatic factors, demonstrating that rising temperatures adversely affect staple crops such as maize, millet, and sorghum, while adequate precipitation plays a critical role in enhancing yields. Socio-economic factors, including disparities in resource access between northern and southern regions, influence farmers’ adaptive capacity and resilience to climate variability. Adaptation strategies adopted by Nigerian farmers, such as adjusted planting schedules, crop diversification, and irrigation practices, are explored within the context of socio-economic constraints and infrastructural limitations. Spatial analysis using GIS provides insights into the differential impacts of climate variability across Nigeria, emphasizing the vulnerability of northern regions to climate shocks compared to the relative resilience of southern regions. Policy implications underscore the urgency of promoting climate-resilient agricultural practices, improving resource access, enhancing rural infrastructure, and implementing targeted capacity-building initiatives. These measures are essential for enhancing adaptive capacity, resilience, and sustainable agricultural development amidst on going climate variability and change in Nigeria.

Intra-Urban Livestock Breeding in the Sahel Zone and the Living Environment of City Dwellers in Maroua, Far Nord, Cameroon

Intra-Urban Livestock Breeding in the Sahel Zone and the Living Environment of City Dwellers in Maroua, Far Nord, Cameroon

Groundwater Dynamics in African Endorheic Basins in Arid to Semi-Arid Transition Zones: The Batha Aquifer System, NE Chad

This study investigates the Batha endorheic basin in Chad, situated east of the Lake Chad basin in the arid to semi-arid Sahelian zone. This region has not yet undergone comprehensive geological and hydrogeological studies. More broadly, the transition zone between semi-arid and arid climates has been minimally explored. This research aims to evaluate the resources and dynamics of this multi-layered system using a combined geology-hydrogeology-hydrochemistry-isotopes approach. The multilayer system includes sedimentary layers (Quaternary, Pliocene, and Eocene) over a crystalline basement. A piezometric investigation of the system shows a general SE–NW groundwater, indicating an interconnection between all layers. Hydrochemical analyses identifies four main facies (calcium-bicarbonate, sodium-bicarbonate, sulphate-sodium, and mixed), primarily controlled by water–rock interaction with secondary influences from base-exchange and evaporation. Saturation indices indicate that these waters are close to equilibrium with the calcite-Mg phases, gaylussite and gypsum. Stable isotopes (oxygen-18 and deuterium) categorize groundwater into three groups: ancient water, recent and older meteoric water mixtures affected by evaporation, and mixtures more heavily impacted by evaporation. Tritium contents reveal three groups: current rainwater, modern water, and sub-modern water. These results indicate that ionic and isotopic differentiations cannot be strictly linked to specific layers, confirming the interconnected nature of the Batha system. The observed heterogeneity is mainly influenced by lithological and climatic variations. This study, though still limited, enhances significantly the understanding of the basin’s functioning and supports the rational exploitation of its vital resources for the Batha area’s development. Future investigations to complete the present study are highlighted.

Assessment of the Influence of zaï, Stone Rows, and Organo-mineral Fertiliser on Soil Properties and Groundnut Yields Performances in Sudan Sahelian Zone of Burkina Faso

Groundnut occupies a vital position in oilseed crop production in Burkina Faso, with current production at 630,526 tonnes. However, its production faces threats from drought and low soil fertility. This study aims to determine the influence of zaï, stone rows, ridge tillage, and mineral fertilisation on soil health and on groundnut yields performances in Sudan Sahelian zone of Burkina Faso. Experimental treatments were distributed randomly following a Fisher block design, comprising four treatments and five replications, in the village of Sandogo. Data on soil properties, plant growth, and yields were analysed using variance analysis in R software. The results indicate significant influences of the treatments on carbon content, nitrogen content, phosphorus content, pH values, soil moisture content, soil carbon dioxide release, and soil macrofauna. Moreover, notable effects were observed on the number of nodules, drier nodule weight, number of leaves and branches, pod load, pod and straw yields, and the weight of 100-pods. The highest carbon content (0.857; 0.861%), nitrogen content (0.081%; 0.087%), phosphorus content (7.488; 7.735 mg.kg-1), pH values (6.43; 6.54), and soil moisture content (24.80; 25.27%) were recorded in the homogeneous group of zaï and zaï associated to stone rows. The highest carbon dioxide release (2863.33 ppm) was recorded in plots treated with stone rows. Ants were the most widely encountered macrofauna, whereas no earthworms were recorded. The highest performance in terms of the number of nodules (84.76; 87.88), dry nodule weight (0.0893; 0.0886 g/plant), number of leaves (40; 40), number of branches (6; 6), pod load (25; 25), weight of 100-pods (112.90; 111.98 g), straw yields (1673.28; 1664.87 kg.ha-1), and pod yields (2122.32; 2161.96 kg.ha-1) were achieved with zaï and zaï combined with stone rows. Zaï and zaï combined with stone rows can therefore be used as effective alternatives to improve groundnut production in the Sudan Sahelian zone of Burkina Faso in a context of climate change, while protecting the environment.

Prevalence and risk factors for gastrointestinal parasitosis in small ruminant farms in the Sahelian zone of Niger

The general aim of this study is to analyse the risk factors for gastrointestinal parasitosis in small ruminants in order to contribute to the emergence of targeted treatment methods, at herd and agro-climatic zone levels, for the integrated and sustainable management of parasitic diseases in Sahelian livestock systems. The methodology was based on a questionnaire survey conducted in 37 villages and coprological analysis using the McMaster method on faecal samples from 968 small ruminants, including 555 goats and 413 sheep. Multiple logistic regression was used to highlight the risk factors associated with each type of parasitosis encountered. The results showed that the most widespread farming system remained 100% traditional, with feeding based essentially on natural grazing. Coprological results showed the prevalence of nematodosis (70.2%), Cestodosis (4.1%) and Coccidiosis (79.9%), with an average prevalence of coinfection of 56.9%. These parasite loads were significantly higher during the rainy season and in the more arid northern Sahelian zone, with a marked reduction at the end of the season. Average parasitic egg excretions were 1089 EPG of nematodes and 6864 EPG of coccidia. Parasite loads were higher in the wetter southern strip and varied significantly by breed. Of the five breeds of small ruminants studied, the ara-ara sheep had the highest parasitic loads and prevalences for nematodosis (78.6%), coccidiosis (89,3%) and coinfection (70.9%), appears to be the most susceptible to parasitosis. As for risk factors for severe parasite pressure, animals at the end of the rainy season, older animals and those with poor body condition were at risk of nematodiasis or coinfection. On the other hand, animals at the beginning of the rainy season, farms located in less arid southern Sahelian zones and male subjects were the groups at significant risk of coccidiosis. In these extensive Sahelian farming conditions, the control of these parasitoses by selective treatment of animals could be developed, targeting in particular the risk groups highlighted in this study.

Droughts and heatwaves in the West African monsoon system

AbstractHeatwaves and droughts increasingly impact public health and societal system in a world subject to global warming. Several studies reported these phenomena all around the world, but there is a dearth of research specifically in West Africa. This study fills that gap by comparing heatwave/heat stress and drought occurrence in three climate zones (Guinea, Sudan and Sahel) of West Africa from 1981 to 2020. The analysis focuses on the comparison of station and gridded datasets. The Cumulative Excess Heat (CumHeat) and the Universal Thermal Climate Index (UTCI) are considered for heatwaves. For drought, the Standardized Precipitation (Evapotranspiration) Index SPI (SPEI) are used at 3‐, 6‐ and 12‐month scales. Both heatwave and drought characteristics are investigated as well as their co‐occurrence (D‐HW). The investigation reveals a good correlation between station and gridded datasets for drought indices. While station data records fewer and less intense heatwave, gridded data indicates longer‐lasting heat extremes. The study also demonstrates a strong agreement between the UTCI computed from the Rayman model and ERA5‐HEAT dataset, despite timing discrepancies, especially along the Guinea coast. The Sahel region is found to endure higher heat stress levels, with increasing intensity of heatwaves over time. Notably, the study uncovers an increasing frequency of compound D‐HW in all zones, especially the Sudan and Sahel zones, offering new insights into the climatic challenges faced by West Africa. These findings emphasize the critical need for improved planning and early warning systems (EWS) to mitigate the impacts of these climate extremes ecosystems and human health.

Spatiotemporal distribution of Eurasian Spoonbills (Platalea leucorodia) outside the Carpathian Basin – the results of the Hungarian colour-ringing project based on twenty years (2003–2023)

Abstract The Eurasian Spoonbill (Platalea leucorodia) is a migratory waterbird. We used the confirmed observations of colour-ringed individuals (2,735 specimens) of the Hungarian population collected outside the Carpathian Basin between May 2003 and February 2023. 546 Spoonbills occurred in 28 countries. They used mainly the Central Mediterranean Flyway, however, some individuals were seen along the East Atlantic Flyway or the East Mediterranean Flyway. Three individuals were observed north of the Alps, too. A small proportion of Spoonbills crossed the Sahara and they occurred in the Sahel zone, between Sudan in the east and Senegal and Mauritania in the west. A few individuals were observed on Saharan wetlands in Algeria during winter. The most important destination for the Hungarian (Pannonian) population during the migration is Tunisia, where many of them spend the winter, primarily in the tidal area of the Gulf of Gabes. The first adults reached North Africa (Tunisia) on 28 July during their southward migration, while the last ones stayed there until 23 April. The first observation of juveniles in North Africa (Tunisia) happened on 31 August. Immature, 2- and 3-cyold birds spend the summer in unknown numbers in Tunisia. The majority of Pannonian Spoonbills migrate through the Balkans and Italy and some stay there to winter, mainly in Italy. Some of the immatures spent the summer in Italy. In southern Europe, the peak of the spring migration was in March, and the peak of the autumn migration was in September. There was also a difference in the migration of different age groups: in Southern Europe, the migration peak of adult birds falls between March and April, while most of the immatures were observed in May and June during northward migration. The peak of the southward migration in all age groups was observed in September. In the southern part of Europe, there may still be adults migrating north on 13 May, while other adults may already migrate southward on 15 May. The earliest juvenile migrating south was documented on 30 June in Italy.

Evaluation of Gridded Rainfall Products in Three West African Basins

In recent years, accessing rainfall data from ground observation networks maintained by national meteorological services in West Africa has become increasingly challenging. This is primarily due to high acquisition costs and the often sparse distribution of rainfall gauges across the region, which limits their use in hydrological studies and related research. At the same time, the rising availability of precipitation products derived from satellite/earth observations, reanalysis datasets, and in situ measurements presents exciting prospects for hydrological applications. Nonetheless, these datasets constitute indirect measurements, necessitating rigorous validation against ground-based rainfall data. This study comprehensively assesses twenty-three gridded rainfall products, including sixteen from satellites, six from reanalysis data, and one from in situ measurements, across the Senegal, Gambia, and Casamance River basins. Performance evaluation is conducted across distinct climatic zones, both pre- and post-resampling against observed rainfall data gathered from forty-nine rainfall stations over a six-year period (2003–2008). Evaluation criteria include the Kling–Gupta Efficiency (KGE) and Percentage of Bias (PBIAS) metrics, assessed at daily, monthly, and seasonal time steps. The results reveal distinct performance levels among the evaluated rainfall products. RFE, ARC2, and CPC notably yield the highest KGE scores at the daily time step, while GPCP, CHIRP, CHIRPS, RFE, MSWEP, ARC2, CPC, TAMSAT, and CMORPHCRT demonstrate superior performance at the monthly time step. During the rainy season, these products generally exhibit robustness. However, rainfall estimates derived from reanalysis datasets (ERA5, EWEMBI, MERRA2, PGF, WFDEICRU, and WFDEIGPCC) perform poorly in the studied basins. Based on the PBIAS metric, most products tend to underestimate precipitation values, while only PERSIANN and PERSIANNCCS lead to significant overestimations. Spatially, optimal performance of the products is observed in the Casamance basin and the Sudanian and Sahelian climatic zones within the Gambia and Senegal basins. Conversely, in the Guinean zone of the Gambia and Senegal Rivers, the rainfall products displayed the poorest performance.

Feed balances for ruminant livestock: gridded estimates for data−constrained regions

Demand for animal−source foods and livestock feed are forecast to increase across sub-Saharan Africa. In this context, there is a need to estimate the availability of livestock feed to support decision−making at local, sub-national and national levels. In this study, we assess feed balances for ruminant livestock in Ethiopia and Burkina Faso. Feed availability was estimated using remotely sensed products and detailed feed composition data. Feed requirements were estimated for maintenance, growth, lactation, gestation and locomotion using a data−intensive model. Biomass available as animal feed was estimated to be 8.6 tonnes of DM per hectare in the Ethiopian highlands and midlands, 3.2 tonnes DM per hectare in the Ethiopian lowlands, 2.9 tonnes DM per hectare in Burkina Faso’s Sudanian agro-ecological zone and 1.0 tonne DM per hectare in the Sahel. The energy requirements of lactating cows were estimated to be 62.1 Megajoules (MJs) per animal per day in the Ethiopian highlands and midlands, 62.7 MJ in the Ethiopian lowlands, 88.5 MJ in Burkina Faso’s Sudanian agro-ecological zone and 53.1 MJ per animal per day in the Sahel. Feed scarcity hotspots are most prominently located in the Ethiopian highlands and the Sahelian agro-ecological zone of Burkina Faso. Demand−side policy and investment initiatives can address hotspots by influencing herd sizes, nutritional requirements and herd mobility. Supply−side policy and investment initiatives can secure existing feed resources, develop new sources of feed and incentivise trade in feed resources. Improving feed balances will be of value to decision−makers with the aims of optimising livestock productivity, minimising exposure to climatic shocks and minimising greenhouse gas emission intensity.

Evaluation of Satellite-Based Rainfall Estimates against Rain Gauge Observations across Agro-Climatic Zones of Nigeria, West Africa

Satellite rainfall estimates (SREs) play a crucial role in weather monitoring, forecasting and modeling, particularly in regions where ground-based observations may be limited. This study presents a comprehensive evaluation of three commonly used SREs—African Rainfall Climatology version 2 (ARC2), Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) and Tropical Application of Meteorology using SATellite data and ground-based observation (TAMSAT)— with respect to their performance in detecting rainfall patterns in Nigeria at daily scales from 2002 to 2022. Observed data obtained from the Nigeria Meteorological Agency (NiMet) are used as reference data. Evaluation metrics such as correlation coefficient, root mean square error, mean error, bias, probability of detection (POD), false alarm ratio (FAR), and critical success index (CSI) are employed to assess the performance of the SREs. The results show that all the SREs exhibit low bias during the major rainfall season from May to October, and the products significantly overestimate observed rainfall during the dry period from November to March in the Sahel and Savannah Zones. Similarly, over the Guinea Zone, all the products indicate overestimation in the dry season. The underperformance of SREs in dry seasons could be attributed to the rainfall retrieval algorithms, intensity of rainfall occurrence and spatial-temporal resolution. These factors could potentially lead to the accuracy of the rainfall retrieval being reduced due to intense stratiform clouds. However, all the SREs indicated better detection capabilities and less false alarms during the wet season than in dry periods. CHIRPS and TAMSAT exhibited high POD and CSI values with the least FAR across agro-climatic zones during dry periods. Generally, CHIRPS turned out to be the best SRE and, as such, would provide a useful dataset for research and operational use in Nigeria.

Enhancing tree species conservation in Burkina Faso through indigenous knowledge

Natural resources such as plant plays an important role in the livelihood of many local people in Africa. The high anthropogenic pressure on plant resources lead to their disappearance. Assessing ethnobotanical knowledge is useful for development of management and conservation of plant resources. Focusing on woody plants, our ethnobotanical investigations involved 60 randomly selected households across two Sahelian villages. Through semi-structured interviews, we meticulously assessed indigenous knowledge and perceptions related to the conservation of 41 woody plant species spanning 32 genera and 15 families.Our analysis categorized these species based on their diverse uses, encompassing food, medicine, fodder, construction, energy and art. The most dominant families reported Fabaceae and Combretaceae followed by Malvaceae. Notably, fruits, leaves, bark, and seeds emerged as the most valued plant organs.Crucially, our findings pinpointed human activities as the primary threat to species conservation, overshadowing climatic factors. We further identified key species and prioritized those in need of urgent conservation efforts. This study underscores the imperative of incorporating indigenous knowledge and perceptions into the development of effective conservation management strategies for plant resources in Sahelian zone.

Study of goat rearing systems and their impact on young goat production in the Sahelian zone of Africa: The case of West Mayo-Kebbi, Chad

Study of goat rearing systems and their impact on young goat production in the Sahelian zone of Africa: The case of West Mayo-Kebbi, Chad

Numerical Study of the Thermal Behavior of a Wall Containing Phase Change Material (PCM) in a Hot and Dry Climate

Current buildings in Burkina Faso, particularly in the Sahelian zone, built with local materials are energy-intensive and sources of discomfort for the occupants. However, the role of housing is to provide man with shelter which protects him from external climatic conditions and offers him thermal comfort. In this work, we present a numerical study of the thermal behavior of a wall containing a phase change material (PCM) in the Sahelian zone. The MCP used in this study is RT27 paraffin with a melting temperature of 27°C and a latent heat of fusion of 179kJ/kg. The equations obtained were adimensionalized and discredited by the finite element method and solved using COMSOL Multiphysics software version 5.3. To this end, we were interested on the one hand in the study of the evolution of the flow of heat and the temperature at the level of the external and internal walls of the wall. On the other hand, we studied the effect of the location of a layer of PCM mortar, simple plaster or cement plaster on the temperature of the internal wall of the wall. The results show the magnitude of heat flux and temperature is greatly reduced by the incorporation of PCM into the wall.