Search Results (26)

This study analyzed terrestrial water storage (TWS) changes across the Inner Niger Delta (IND) in Mali (West Africa) from April 2002 to September 2022 using Gravity Recovery and Climate Experiment (GRACE), GRACE-Follow-On (GRACE-FO), and Global Land Data Assimilation System (GLDAS) products. TWS changes exhibited strong seasonal patterns (−170 mm to 330 mm) with a high correlation between GRACE/GRACE-FO and GLDAS (r = 0.92, RMSE = 35 mm). The TWS trend was positive (7.3 to 9.5 mm/year). Maximum TWS changes occurred in September, while minimum values were observed between April and May. Wavelet analysis identified dominant seasonal cycles (8–16 months). Finally, we examined the climatic effects on TWS changes along the Niger River, from its source in the humid zones of Guinea to the semi-arid Sahelian zones of the IND in Mali. Precipitation (P) and potential evapotranspiration (PE) influence TWS changes only in the humid regions (r = 0.18–0.26, p-value < 10⁻²). Surface water bodies (SWB) exhibited a significant correlation with TWS in all regions, with r exceeding 0.50 in most cases. Groundwater changes, estimated from GRACE/GRACE-FO and GLDAS, showed strong agreement (r > 0.60, RMSE < 120 mm), with recharge rates increasing in semi-arid and Sahelian regions (r > 0.70, p-value < 10⁻³). This study highlights that precipitation, surface water bodies, and groundwater recharge appear as primary drivers of TWS in different regions: precipitation in the humid forest of Guinea, surface water bodies in the Southern and Northern Guinea Savanna along the Guinea–Mali border, and groundwater recharge in the semi-arid and IND Sahelian regions of central Mali. Full article

Frankenia is a morphologically complex genus, with some species exhibiting a few diagnostic characters and significant morphological variability. This has led to misidentification or the synonymisation of many names based on one or a few diagnostic traits. This phenomenon affects the annual sea-heath, F. pulverulenta, a Eurasian–Mediterranean herb that has become subcosmopolitan, to which several entities have been included due to their shared features, namely their annual lifespan or their flattened leaves. However, this fact also extends to shrubby species, such as the Madeiran F. cespitosa. Here, integrative taxonomic studies, encompassing detailed morphological descriptions of macro- and microcharacters along with molecular phylogenetic analyses of both nuclear ribosomal (ITS1-5.8S-ITS2 region) and plastid (matK gene) DNA sequence data, and an analysis of biogeographic data were undertaken. This examination has resulted in the most complete phylogenetic trees of Frankenia to date, leading to the reinstatement of two African species broadly differing morphologically from F. pulverulenta. Firstly, F. florida L.Chevall., a name applied to a species occurring in the Saharan regions of Algeria, Morocco, Mali, and Mauritania, is often accepted as a variety or subspecies of the annual sea-heath. In contrast, F. densa Pohnert, a species endemic to southern Namibia and northern South Africa, has been synonymised with F. pulverulenta. However, since those two names were later homonyms of two Chilean and Australian plants, they were deemed illegitimate upon publication. Consequently, two new names are proposed for them: F. sahariensis and F. dinteri, respectively. Their substantiation as independent species is provided by data on their morphology, distribution, ecology, and molecular phylogenetics, which demonstrate their distinctiveness from F. pulverulenta. Nomenclatural synonymy and types are also presented for all concerned names, including the designation of two new lectotypes. Furthermore, the importance of an accurate description of the morphological variation in populations is emphasised for a precise identification of taxa in Frankenia. Full article

The increasing demand for carbon-free energy in recent years has positioned hydrogen as a viable option. However, its current production remains largely dependent on carbon-emitting sources. In this context, natural hydrogen, generated through geological processes in the Earth’s subsurface, has emerged as a promising alternative. The present study provides the first national-scale assessment of natural dihydrogen (H₂) potential in Uruguay by developing a catalog of potential H₂-generating rocks, identifying prospective exploration areas, and proposing H₂ systems there. The analysis includes a review of geological and geophysical data from basement rocks and onshore sedimentary basins. Uruguay stands out as a promising region for natural H₂ exploration due to the significant presence of potential H₂-generating rocks in its basement, such as large iron formations (BIFs), radioactive rocks, and basic and ultrabasic rocks. Additionally, the Norte Basin exhibits potential efficient cap rocks, including basalts and dolerites, with geological analogies to the Mali field. Indirect evidence of H₂ in a free gas phase has been observed in the western Norte Basin. This suggests the presence of a potential H₂ system in this area, linked to the Arapey Formation basalts (seal) and Mesozoic sandstones (reservoir). Furthermore, the proposed H₂ system could expand exploration opportunities in northeastern Argentina and southern Brazil, given the potential presence of similar play/tramp. Full article

The mosquito Culex pipiens occurs in two ecotypes differing in their mating and overwintering behavior: pipiens mate in open environments and diapause, and molestus also mate in small spaces and is active throughout the year. Cx. pipiens carry Wolbachia endosymbionts of the wPip strain, but the frequency of infection differs between studied populations. Wolbachia infection affects the host reproductive success through cytoplasmic incompatibility. wPip Wolbachia is divided into five types, wPip I–V. The type of wPip carried varies among Cx. pipiens populations. In northern European locations different wPip types are found in the two ecotypes, whereas in southern locations, they often carry the same type, indicating differences in hybridization between ecotypes. In this study, Cx. pipiens specimens of both ecotypes were collected from Sweden and compared to specimens from Norway, England, Italy, and the Netherlands, as well as Cx. quinquefasciatus from Mali and Thailand. The abundance varied, but all specimens were infected by Wolbachia, while the tested specimens of other mosquito species were often uninfected. The wPip strains were determined through the sequence analysis of Wolbachia genes ank2 and pk1, showing that Cx. pipiens ecotypes in Scandinavia carry different wPip strains. The observed differences in wPip strains indicate that hybridization is not frequent and may contribute to barriers against hybridization of the ecotypes in Sweden and Norway. Full article

Wood characteristics and properties are related to various factors connected to the biochemical processes that occur in the tree during wood formation, but also, to the interactions with the environmental conditions at the tree growing location. In addition to climatic factors, several investigations drew attention to the significance of the influence of other environmental parameters at the tree growing location. In this perspective, this work aimed to characterize the variation in color and chemical composition of timber wood from different locations in southern Mali, of trees growing under the same climatic conditions. To do so, a total of 68 grounded wood samples, from 4 timber wood species (Daniellia oliveri, Isoberlinia doka, Khaya senegalensis, and Pterocarpus erinaceus), were analyzed using CIELab color space and FTIR-ATR. Overall, the results indicated that the variation in wood color and chemical properties can be related to the local environmental conditions. Pterocarpus erinaceus presented significant differences between samples from the three areas according to the highest number of variables (color parameters, molecular composition determined by FTIR-ATR spectroscopy, and FTIR-ATR ratios). Daniellia oliveri and Khaya senegalensis, however, showed significant differences between areas of provenance for a lower number of variables. Isoberlinia doka, for its part, showed no significant differences and seems to be less sensitive to environmental factors. Furthermore, the results revealed that important differences exist between wood samples from Kati and Kéniéba. Full article

In Mali, hepatocellular carcinoma (HCC) is the third and sixth most common cancer in men and women, respectively. Mali comprises several distinct climato-ecological zones. Most studies to date have been conducted in the sub-Sahelian zone of southern Mali, including the capital city Bamako. In this part of the country, the main risk factors for HCC are chronic hepatitis B virus (HBV) carriage and dietary exposure to aflatoxins, a well-known hepatocarcinogen. Data are scarce for other ecological zones, but our preliminary data from 721 blood donors in the area of Timbuktu, presented in this study, suggest that chronic HBV carriage is also endemic in the northern Saharan zone of Mali. For further study, 29 healthy HBV chronic carrier volunteers were recruited from the blood transfusion center in Timbuktu. Successful viral genotyping in 20 volunteers revealed HBV genotype E in 13 cases and D in 7 cases, suggesting that this geographical and anthropological transition zone may also represent a transition zone between HBV genotypes that dominate sub-Saharan and northern Africa, respectively. Sequencing of circulating cell-free plasma DNA (cfDNA) from donors did not reveal the presence of the TP53 R249S mutation in these donors, a marker of dietary exposure to aflatoxins in sub-Saharan Africa. These results suggest that the geo-epidemiological distribution of the risk factors for HCC is not uniform across Mali, but is dependent upon climatic, socioeconomic and anthropological factors that might have an impact on patterns of chronic liver disease and cancer. Full article

Onion is one of the most economically and nutritionally important vegetable crops in West Africa. Onions are very important for consumers due to the antioxidants and compounds they contain that may reduce inflammation, lower triglycerides and reduce cholesterol levels, resulting in lower risks of heart disease and blood clots. However, high-yielding varieties that are accessible to farmers remain scarce. The objective of the present study was to identify adapted onion genotypes for sustainable production in Northern Ghana and Southern Mali. Nine onion lines, including a check variety, were assessed for yield stability using a randomized complete block design. The trials were carried out in “technology parks” under the joint management of farmers and researchers. Onion bulb weight was recorded for each plot after harvest. Separate analyses of variances were performed for each location and season. Analysis of variance of combined locations, seasons and lines was performed to determine the most stable varieties using the line-superiority measure and ecovalence stability coefficients. Results indicated that the lines AVON1310 and AVON1325 were most stable for yield performance over locations and seasons (Wi = 2.20 and 11.60, respectively; Pi = 1.32 and 6.56, respectively). From the genotype main effects and genotype-by-environment interaction biplots, the best performing lines were AVON1310 (33.32 t.h⁻¹), AVON1308 (28.81 t.h⁻¹) and AVON1325 (31.68 t.h⁻¹). The stability of these lines makes them potential candidates for commercial release in West Africa to contribute to sustainably intensifying onion production in the region. Full article

Agricultural development across much of sub-Saharan Africa is constrained by the gap in knowledge on site suitability for sustainably expanding irrigable lands to new areas. This study aimed to identify the most suitable sites for promoting small-scale irrigation in Mali based on environmental and land use/land cover criteria. Six thematic layers were integrated to consider the water accessibility (distance from surface water and groundwater potential), soil, climate conditions, slope, and land use/land cover. Subjective scores and weights were assigned to each of the six layers, which were integrated to select the most suitable sites according to five categories ranging from ‘very high’ to ‘very low’. Results indicated that 641,448 ha of land have a very high potential for small-scale irrigation expansion: these are mostly located in the central Segou region (53% of the total very high potential sites across the country) and around the capital district, Bamako, in southern Koulikoro (38% of the total very high potential sites across the country). Sites ranked second as having high potential are also distributed in southern Segou, central Koulikoro, and the western Kayes and Mopti regions, totaling 20.8 Mha. Moderate potential sites are generally located in the northwestern and southern parts accounting for 37.8 Mha of the country, whereas low and very low potential sites are concentrated in the northern and eastern parts of the country over a total area of 65 Mha. The present study demonstrates the usefulness of remote sensing and GIS techniques in agricultural development planning at large-scale; similar methodologies can be applied in other sub-Saharan African countries. Full article

Climate variability and change greatly affect agricultural and water resource management over West Africa. This paper presents the current characteristics and projected change in regional crop water demand (CWD), irrigation requirement (IR), and water availability (WA) over West Africa. Observed and simulated daily rainfall, minimum temperature, maximum temperature, and evapotranspiration are used to derive the above agro-meteorological and hydrological variables. For future periods, high-resolution climate data from three regional climate models under two different scenarios, i.e., representative concentration pathway (RCP) 4.5 and 8.5, are considered. Evaluation of the characteristics of present-day CWD, IR, and WA indicated that the ensemble mean of the model-derived outputs reproduced the prevailing spatial patterns of CWD and IR. Moreover, the wetter part of the domain, especially along the southern coast, was correctly delineated from the drier northern regions, despite having biases. The ensemble model also simulated the annual cycle of water supply and the bimodal pattern of the water demand curves correctly. In terms of future projections, the outcomes from the study suggest an average increase in the CWD by up to 0.808 mm/day and IR by 1.244 mm/day towards the end of the twenty-first century, compared to the baseline period. The hot-spot areas, where there is higher projected increment in CWD and IR, are over Senegal, Southern Mali, and Western Burkina Faso. In most cases, WA is projected to decrease towards the end of the twenty-first century by −0.418 mm/day. The largest decline in WA is found to be over Guinea and most of the eastern parts of West Africa. Despite the current under-utilization of the existing groundwater resources, the threat of global warming in reducing future WA and increasing CWD suggested caution on the scale of irrigation schemes and management strategies. The outcomes from the study could be a crucial input for the agricultural and water managers for introducing effective measures to ensure sustainability of irrigated farm lands. Full article

Tomato is an important vegetable crop and plays a major role in the food and nutrition security of the people of Mali. Production has increased in the recent decades but improvement in the fruit yield and quality remains suboptimal. Limited access to the best-adapted tomato varieties to the local conditions, pests and diseases are the major limiting factors for improving productivity. This study evaluated the performance of different tomato entries and varieties for their productivity, resistance to pests and diseases and postharvest fruit quality in Mali. Twenty-two entries and varieties of tomato in the rainy season and twenty-four in the dry season were evaluated. Varieties that were well adapted, better yielded, disease resistant and with good fruit quality were identified. Major plant diseases observed included tomato yellow leaf curve disease (TYLCD), bacterial wilt, bacterial leaf spot, early blight and southern blight. However, TYLCD was the major problem during the dry season. The variety of Icrixina was the most affected by TYLCD in both the rainy and dry seasons, although its total yield was not affected and remained one of the highest. Konica was one of the most susceptible varieties to bacterial wilt and bacterial leaf spot diseases. Tomato accession AVTO1710 provided the highest fruit yield (40.9 t/ha), while AVTO1704 provided the lowest (6.50 t/ha) in the rainy season. In contrast the highest yield during the dry growing season was 20 t/ha from VIO43614. Tomato entries and varieties varied in their postharvest fruit quality attributes (firmness, total soluble solid, pH and dry matter). Production season clearly influenced yield, disease occurrence and severity, as well as postharvest fruit qualities. The study identified better disease-resistant and yielding tomato entries suitable for rainy and dry growing seasons, which can be considered and scaled up for production so that farmers in Mali can produce tomato all year round. Full article

The depletion of soil organic matter is one of the major challenges constraining agricultural production in the southern zone of Mali. This study evaluated the effects of compost types, methods, and dose applications on the productivity and sustainability of sorghum. Two types of compost (farmer practice and cotton stems) were applied to sorghum at two rates (microdosing at 2.5 t ha⁻¹ and broadcasting at 5 t ha⁻¹) and evaluated on 30 farmer fields in 2019 and 2020. The treatments used included CPA (cotton stem compost at 5 t ha⁻¹ + 100 kg ha⁻¹ DAP), CPA (cotton stem compost at 2.5 t ha⁻¹ + 100 kg ha⁻¹ DAP), CP (farmer compost at 5 t ha⁻¹ + 100 kg ha⁻¹ DAP), CP (famer compost at 2.5 t ha⁻¹ + 100 kg ha⁻¹ DAP), control (100 kg ha⁻¹ DAP), and control. The results showed that regardless of the compost type, applying a microdose of 2.5 t ha⁻¹ improved the growth rate, plant height, grain yield, and biomass yield by 15%, 18%, 47%, and 27%, respectively, when compared to the control. No statistical difference was observed in the yield of 2061 kg ha⁻¹ between applying compost by microdosing at 2.5 t ha⁻¹ and broadcasting at 5 t ha⁻¹. It can be inferred that the application of compost by microdosing makes it possible to achieve a 100% fertilized surface compared to broadcasting, with a nitrogen use efficiency of more than 55%. The application of compost by microdosing at 2.5 t ha⁻¹ resulted in an economic gain of 334,800 XOF ha⁻¹, which was 27% higher than that obtained with the application of compost by broadcasting at 5 t ha⁻¹. Conversely, the contribution to the improvement of soil nitrogen stock varied from 12–20% with a microdose of 2.5 t ha⁻¹ compared to 100% for broadcasting compost at 5 t ha⁻¹ per application. Therefore, the availability of cotton stems in the southern zone of Mali presents an opportunity for farmers to implement compost microdose technology to double the fertilized area and improve sorghum productivity. Full article

Droughts are one of the world’s most destructive natural disasters. In large regions of Africa, droughts can have strong environmental and socioeconomic impacts. Understanding the mechanism that drives drought and predicting its variability is important for enhancing early warning and disaster risk management. Taking North and West Africa as the study area, this study adopted multi-source data and various statistical analysis methods, such as the joint probability density function (JPDF), to study the meteorological drought and return years across a long term (1982–2018). The standardized precipitation index (SPI) was used to evaluate the large-scale spatiotemporal drought characteristics at 1–12-month timescales. The intensity, severity, and duration of drought in the study area were evaluated using SPI–12. At the same time, the JPDF was used to determine the return year and identify the intensity, duration, and severity of drought. The Mann-Kendall method was used to test the trend of SPI and annual precipitation at 1–12-month timescales. The pattern of drought occurrence and its correlation with climate factors were analyzed. The results showed that the drought magnitude (D_M) of the study area was the highest in 2008–2010, 2000–2003, and 1984–1987, with the values of 5.361, 2.792, and 2.187, respectively, and the drought lasting for three years in each of the three periods. At the same time, the lowest D_M was found in 1997–1998, 1993–1994, and 1991–1992, with D_M values of 0.113, 0.658, and 0.727, respectively, with a duration of one year each time. It was confirmed that the probability of return to drought was higher when the duration of drought was shorter, with short droughts occurring more regularly, but not all severe droughts hit after longer time intervals. Beyond this, we discovered a direct connection between drought and the North Atlantic Oscillation Index (NAOI) over Morocco, Algeria, and the sub-Saharan countries, and some slight indications that drought is linked with the Southern Oscillation Index (SOI) over Guinea, Ghana, Sierra Leone, Mali, Cote d’Ivoire, Burkina Faso, Niger, and Nigeria. Full article

Precise agricultural predictions of climate change effects on crop water productivity are essential to ensure food security and alleviate water scarcity. In this regard, the present study provides an overview of the future impacts of climate change on the irrigation of agricultural products such as rice, millet, maize, cassava, sorghum, and sugar cane. These crops are some of the most-consumed foodstuffs in countries of the Niger River basin. This study is realized throughout 2020 to 2080, and three Global Climate Models (GCMs) (CSIRO, MIROC5, and ECHAM. MPI-ESM-LR) have been used. The GCMs data have been provided by the IPCC5 database. The irrigation water requirement for each crop was calculated using Smith’s CROPWAT approach. The Penman–Monteith equation recommended by the FAO was used to calculate the potential evapotranspiration. The inter-annual results of the IWR, according to the set of models selected, illustrate that the largest quantities of water used for irrigation are generally observed between January and March, and the lowest quantities are the most often seen between July and September. The majority of models also illustrate a peak in the IWR between March and April. Sorghum and millet are the crops consuming the least amount of water for irrigation; followed by cassava, then rice and corn, and finally sugar cane. The most significant IWRs, which have been predicted, will be between 16.3 mm/day (MIROC5 model, RCP 4.5) and 45.9 mm/day (CSIRO model, RCP 4.5), particularly in Mali, Niger, Algeria, and rarely in Burkina-Faso (CSIRO model, RCP4.5 and 8.5). The lowest IWRs predicted by the models will be from 1.29 mm/day (MIROC5 model, RCP 4.5) to 33.4 mm/day (CSIRO model, RCP 4.5); they will be observed according to the models in Guinea, southern Mali, Ivory Coast, center and southern Nigeria, and Cameroon. However, models predict sugarcane to be the plant with the highest IWR, between 0.25 mm/day (Benin in 2020–2040) and 25.66 mm/day (Chad in 2060–2080). According to the models’ predictions, millet is the crop with the most IWR, between 0.20 mm/day (Benin from 2020 to 2060) and 19.37 mm/day (Chad in 2060–2080). With the results of this study, the countries belonging to the Niger River basin can put in place robust policies in the water resources and agriculture sectors, thus ensuring food security and high-quality production of staple crops, and avoiding water scarcity while facing the negative impacts of climate change. Full article

The total fertility rate in Mali (6.2) is the third highest in the world. Despite sociocultural similarities, the total fertility rate in neighboring Senegal is 4.2. The aim of this study is to identify factors which may help to explain the differences between the two countries and which may thereby inform family planning policy in Mali. A cross-sectional study was conducted with a convenience sample of 602 married women aged 16–50 from urban and rural sites in southern Mali and Senegal. A total of 298 respondents from Mali and 304 from Senegal completed a structured questionnaire between July and October 2018. In total, 11.1% of the Malian respondents and 30.9% of the Senegalese respondents were currently using family planning, and 34.6% and 40.5%, respectively, had ever used a modern family planning method. Pressure from husbands was cited as a primary influence for having more children (in 50.3% of Malians and 45.4% of Senegalese, p = 0.000). Women’s age, education level, and knowledge of different contraceptive methods were associated with ever use of contraceptives. After adjustment for confounders, discussing family planning with one’s husband was the strongest predictor of contraceptive use among both Senegalese (OR = 3.4, 95% CI (1.9–6.3), p = 0.000) and Malian respondents (OR = 7.3, (4.1–13.3), p = 0.000). Full article

For the first time, volatile hydrocarbons were measured in Croatia, at Mali Lošinj in the period from autumn 2004 to autumn 2005. Mali Lošinj site is conveniently located as a gateway to Croatia for any potential pollution from either Po valley in Italy, or other locations in southern Europe or even Africa. The sampling was performed on multisorbent tubes and then analyzed by thermal desorption gas chromatography with a flame ionization detector. The aim was to determine and estimate the non-methane hydrocarbons in Mali Lošinj, a location with Mediterranean vegetation and species which emit large quantities of volatile organic compounds. Ozone volume fraction and meteorological parameters were also continuously measured, from April to October 2005. Ethane, ethene, ethyne, propane, propene, n-pentane, n-hexane, benzene and toluene were identified in all air samples. Benzene and toluene have been found in ambient air and significant positive correlations between ethyne and ethane, propane and propene indicate emissions from transport. Full article