Peanut Basin Research Articles

INFLUENCE OF THE AGRO-ECOLOGICAL ZONES IN SENEGAL ON DIETARY CONSUMPTION OF PEANUT

Peanutisa valuable source of nutrients, but the patterns of peanut consumption, consumption frequencies and factors influencing peanut consumption in Senegal are poorly understood.This study surveyed the populations of four agroecological zones of Senegal:The Peanut Basin (BA), the Lower and Middle Casamance (BMC), the Eastern Senegal and Upper Casamance (SOHC) and the Senegal River Valley (VFS) with the aim of generating data on the consumption of peanut to fill this lack of knowledge and information on this food which represents a good part of the diet of the Senegalese population. The survey sampling plan is designed according to the principles of simple random sampling (SAS) combined with prior stratification. The results of the study showed that peanut-based dishes such as Nieleng in the BA use approximately 1048g of peanut during its preparation. In the VFS, the preparation of Dakhine requires an intake of 692g of peanut. The frequency of consumption of peanut-based dishes also varies according to agro-ecological zones. In the Peanut Basin, Mafe using approximately 465.7g per dish is consumed once or twice a week as is Mbaxalu Saloum in the BMC where 222.8g of peanut are used for a prepared dish. Individual peanut consumption varies depending on the agro-ecological zones. The highest average consumption is noted in the BA with 50.57g. It is followed by the SOHC, the VFS and the BMC with respective values of 41.38g, 25.18g. and 24.73g. People headed by a man in households consume an average of 50g of peanut per day per dish and those headed by a woman, around 40g.Polygamous families consume on average 55.4g of peanut per day per peanut dish. People in families whose chef did not attend school consume on average 51.6g of peanut per dish followed by those whose chef attended Koranic school with 50.9g of peanut per dish per day.

Microbial community shifts in pearl millet root zone soils with Guiera senegalensis intercropping along a rainfall and soil type gradient in the Sahel

AbstractThe Sahel of West Africa has vulnerable agroecosystems that threatens food security. A potential solution is intercropping with the indigenous shrub, Guiera senegalensis J.F. Gmel. Previous research of the Optimized Shrub‐intercropping System (OSS) (high density of ∼1,500 shrubs ha‐1 and coppiced residue incorporation) has been shown to dramatically improve pearl millet [Pennisetum glaucum (L.) R. Br.] yield, which is attributed to improved soil quality, nutrient and water availability, and harboring a distinct microbial community. Whether this response is consistent over a climate and soil type gradient in farmers’ fields has not been investigated. Therefore, the objective was to determine the impact of G. senegalenis on soil chemistry, enzyme activity, microbiomes, and metabolic pathways of millet root zone soils in farmers’ fields. The experiment was a three‐by‐two factorial with three rainfall and soil type sites along a north–south gradient in the Senegal Peanut Basin and two sampling locations (millet root zone soil within and outside the influence of the G. senegalensis). Guiera senegalensis shifted certain predicted bacterial metabolic pathways and enriched some bacterial and fungal genera. Notably, the increased crop growth due to G. senegalensis positively correlated with the abundance of genera having plant growth promoting properties (e.g., Enterobacter agglomerans and Paraburkholderia). Paucibacter, a genera that has deleterious and/or pathogenic properties, was highly abundant in non‐shrub soil but completely suppressed beneath the shrub. The results showed that G. senegalensis in farmers’ fields even at typical, low densities, where coppiced residues are annually burned, still increased soil chemical and microbial properties, suggesting that a more important factor than litter is the presence of shrub roots that provide root turnover and exudates, and water inputs through hydraulic lift.

Assessment of the potential of Vachellia seyal and Prosopis chilensis for the reclamation of saline soil lands in the peanut basin production of Senegal.

Soil properties and microbial activities are indicators that shape plant communities and evolution. We aimed to determine the interdependency between trees, belowground herbaceous plants, soil characteristics, and arbuscular mycorrhizal communities. Vachellia seyal and Prosopis chilensis and their associated herb layers were targeted. Soils sampled beneath the trees and outside the canopies were subjected to physicochemical and microbial characterization. Randomly collected living roots of trees and dominant herbs were checked for arbuscular mycorrhizal colonization. A tree seedlings nursery was conducted using black bags filled with the following substrates: natural soil 100%, soil mixed with leaf tree plants (LTPs) as organic matter at 10%, soil mixed with LTP at 20%, soil mixed with LTP at 30%, and soil mixed with LTP at 50%. As a result, the presence of trees improves both herb richness and diversity. Soil mycorrhizal inoculum potentials are higher beneath V. seyal than P. chilensis and decreased significantly with increasing distance from trees. The soil MIP decreased with increasing organic matter content for both tree species but was more pronounced for P. chilensis. Soil salinity is lower beneath V. seyal and higher under P. chilensis and outside the canopies. Soil fertility parameters such as carbon, nitrogen, and available phosphorus are higher beneath the trees and then decreased as the distance to the trees increases. We conclude that microbial communities, soil properties, and herb richness and diversity increased beneath the trees but decreased with increasing distance from the trees. This effect is tree species-dependent as P. chilensis increased soil salinity and decreased the belowground density of herbs.

Socio-Economic Constraints of Adopting New Cowpea Varieties in Three Agro-Ecological Zones in the Senegalese Peanut Basin

Socio-economic constraints like gender, education, age, and income significantly affect the adoption of improved agricultural technologies. The objective of this study was to determine socio-economic factors that affect the adoption of improved cowpea varieties in the Senegalese peanut basin. The study was conducted in three (Bambey, Kebemer, and Kaffrine) of six regions of the peanut basin based on regional importance of cowpea production and rainfall gradient. In each study region, ten villages were selected, and random sampling was used to select eight heads of agricultural households within each village. The questionnaires were administered to 240 randomly selected farmers across the three study regions, 7 communes, and 30 villages. Results showed most heads of households were middle-aged (52–54 years old), married (95–100%), illiterate (84%), and men (95–100%). Households were mostly agriculture dependent (87%), low literacy rates (26% least primary school), and large family sizes (average of 15 members). The median cowpea yields across the study area varied from 35–100 kg ha−1, well below the ~300–400 kg ha−1 average yields reported for Senegal and Sub-Saharan Africa. The majority of farmers (67%) in the study regions did not use improved varieties, and the main reasons were low seed availability (78.8%) and limited access to technical knowledge and information (76.3%), but only 5.8% indicated seed price as a barrier to improved variety adoption. Major uses of cowpea in the study area were for marketing, livestock feed, and human consumption. In Kaffrine, fodder production was the major (85%) criterion for cowpea variety selection, whereas in the north (Bambey and Kebemer), taste, maturity date, and grain yield were major selection criteria. Factors that had positive effect on the likelihood of using improved cowpea varieties include; access to extension services, membership in farmers’ organization, cowpea being the main crop of production, organic farming, market, and livestock-oriented production systems, access to farmland and credit, dependence on agriculture as the main source of household income, and education of head of household. We conclude that there is a critical need for training, access to improved seeds, awareness, and financial support to producers to increase the adoption of new improved cowpea varieties, yields, profitability, and nutritional security among smallholder farmers in the Senegalese peanut basin.

AgMIP Regional Integrated Assessment of Agricultural Systems in Nioro, Senegal

The Agricultural Model Intercomparison and Improvement Project (AgMIP) developed protocol-based methods for Regional Integrated Assessment (RIA) of agricultural systems. These methods have been applied by teams of scientists working with regional and national stakeholders across Sub-Saharan Africa and South Asia. This paper describes the data sets that were used to implement the AgMIP RIA methods for the Nioro region of Senegal. The goal of the RIA is to assess the potential impacts of climate change on the principal agricultural system in the Senegal peanut basin comprised of peanut, millet, maize and other minor crops and livestock, and to assess adaptations of that system to climate change, under current as well as future climate and socio-economic conditions. The data sets include: the Representative Agricultural Pathways (RAPs) developed for Nioro from 2000-2050; climate data used to implement crop yield simulations; the data used to parameterize the Agricultural Production Systems sIMulator (APSIM) and the Decision Support System for Agrotechnology Transfer (DSSAT) crop models, which include historical climate data and future climate scenarios; and the data used to parameterize the Tradeoff Analysis Model for Multi-dimensional Impact Assessment (TOA-MD) economic simulation model. The analysis is structured around four AgMIP “core questions'' of climate impact assessment.

Single Application of Biochar Increases Fertilizer Efficiency, C Sequestration, and pH over the Long-Term in Sandy Soils of Senegal

This study evaluated the long-term effects of a single application of different biochar types and quantities in combination with cow manure and annual inorganic fertilizer on soil properties and grain yield under millet monocropping and millet–peanut rotation in sandy soils of the peanut basin of Senegal. Results of over six years showed that a single application of 5–10 t ha−1 biochar (rice husk or Typha australis) and/or manure significantly increased soil pH (from 5.5 to 6.3) and total C (from 1.84% to an average of 2.69%). Soil available P increased due to all treatments. These improved soil properties were maintained for at least eight years following a single application of 5–10 t ha−1 biochar and/or manure. There was limited or slightly negative effects of biochar application on soil N and total soil microbial activity. Applications of either one-third or half of national recommended NPK rate, in combination with a single application of biochar or cow manure, increased millet grain yield up to four to five times (i.e., 100 to 450 kg ha−1), which was equivalent to the yield of treatments receiving the full national recommended fertilizer rate. Limited improvement was observed on peanut yield. This research clearly shows the synergistic benefits of applying single low rates of organic materials in combination with annual low levels of inorganic fertilizer. Treatments receiving the national recommended inorganic fertilizer rates (150 kg ha−1 NPK 15-15-15 and 100 kg ha−1 of urea four weeks after planting) did not produce more than 400 kg ha−1. Biochar application alone did not increase millet yields. With a recommended biochar application rate of 5 t ha−1, we calculate that Senegal has enough biomass available for biochar to cover all of its cropland every 4.4 to 5.5 years. Of particular importance, the 0.85% increase in stable total C has the potential to sequester 27.2 tons C ha−1 and if scaled across Senegal’s 1.6–2.0 million ha of peanut and millet cropland, this practice could sequester 43.52 to 54.4 million tons of C having mutual benefits on crop productivity and climate change mitigation.

Enterobacteriaceae, coliform, yeast, and mold contamination patterns in peanuts compared to production, storage, use practices, and knowledge of food safety among growers in Senegal

Peanuts and peanut products are significant revenue sources for smallholder farmers in the Senegalese peanut basin. However, microbial contamination during production and storage can greatly affect market access for producers. Peanut products have emerged as possible sources of foodborne illness, encouraging discussions on international standards for peanuts. In this study, we interviewed 198 households throughout the Senegalese peanut basin to assess current production practices, storage methods, and producers’ prior knowledge of microbial contamination using a 162-question survey. A member of each household orally completed the survey with a trained enumerator and the results were compared to microbiological results obtained from peanut samples collected at the time of the interview using linear regression and an analysis of variance model. Samples were collected from stored peanuts at each household; peanuts were shelled and total Enterobacteriaceae, coliform, and yeast and mold populations were enumerated. Of the 198 samples analyzed, 13.0% and 13.6% were greater than the upper detection limits for Enterobacteriaceae and coliforms, respectively. A total of 21.2% of samples were above the detection limit for yeast and mold populations. Only 22.7% and 18.7% of producers were aware of pathogenic bacteria or aflatoxins, respectively; there were no significant differences in observed microbial populations between household who took preventative measures against microbial contamination and those who did not. Additionally, four households reported washing their kitchen utensils before using them to eat and 60.1% reported always washing their hands before eating. Enumerators were asked to report peanut storage container type and if the containers were stored off the ground at the time of collection. While the interaction between storage container type and if the container was stored off the ground was significant for Enterobacteriaceae and coliforms, it was not significant for yeast and mold. Additionally, when storage container type and if peanuts were stored off the ground were included in the regression model, these methods were predictive of contamination levels for Enterobacteriaceae and coliforms. To our knowledge, this is the first study to analyze the relationship among Enterobacteriaceae, coliforms, and yeast and mold contamination and producer knowledge of Senegalese peanuts. These results provide preliminary data to inform future studies to determine pathogen prevalence and impactful preventative measures to minimize microbial contamination of peanuts produced in Senegal.

Development of an Illumina-based analysis method to study bradyrhizobial population structure-case study on nitrogen-fixing rhizobia associating with cowpea or peanut.

Bradyrhizobia are Gram-negative soil bacteria that regroup a growing number of species. They are widespread in nature and recovered from various biomes that may be explained by a high genetic diversity in this genus. Among the numerous metabolic properties they can harbor, the nitrogen fixation resulting from the association with plants among which important crop legumes (soya bean, peanut, cowpea …) is of great interest, notably in a context of sustainable development. Metabarcoding is widely applied to study biodiversity from complex microbial communities. Here, we demonstrate that using a new species-specific and highly polymorphic 16S-23S rRNA intergenic spacer barcode, we could rapidly estimate the diversity of bradyrhizobial populations that associate with cowpea and peanut plants, two crop legumes of major interest in Senegal. Application of the method on indigenous bradyrhizobia associated with peanut and cowpea grown in soils collected in the center of the peanut basin shows that Bradyrhizobium vignae is a dominant symbiont. We also showed that the two plant species associate with distinct community profiles and that strains introduced by inoculation significantly modified the population structure with these two plants suggesting that application of elite strains as inoculants may well ensure optimized symbiotic performance. This approach may further be used to study the diversity of bradyrhizobia from contrasting agro-eco-climatic zones, to test whether the plant genotype influences the association outputs as well as to estimate the competitiveness for nodule occupancy and the fate of elite strains inoculated in the field.Key points• An amplicon sequencing approach targeting the Bradyrhizobium genus was developed.• Diversity of cowpea and peanut bradyrhizobia from cultivated soils was identified.• The method is well suited to test the competitiveness of defined Bradyrhizobium inoculants.

Landscape heterogeneity analysis using geospatial techniques and a priori knowledge in Sahelian agroforestry systems of Senegal

Agroforestry plays a pivotal role for Sahelian communities by allowing simultaneous improvement of food security and conservation of natural ecosystems and their biodiversity. However, agroforestry systems (AFSs) are particularly heterogeneous in sub-Saharan Africa due to small to very small fields, a large variety of agricultural practices and a diversity of parkland compositions and configurations. This makes spatial sampling processes very important but problematic in terms of representativeness of the landscape heterogeneity to allow an effective study of Sahelian AFSs. In this paper, we proposed, tested and assessed a methodological approach for landscape sampling, mapping and characterization while considering the different types of spatial heterogeneity in complex landscapes, such as Sahelian AFSs. Several complementary methods were combined on the basis of a priori knowledge of agroforestry landscape functioning using multisource data, remote sensing methods, and statistical and spatial analyses applied to landscape ecology. First, the landscape heterogeneity was stratified and used to design two weighted, stratified sampling plans for field surveys of tree species and land use/land cover types. Then, with multisource satellite images together with collected field data, the agroforestry systems were mapped, with a satisfactory accuracy of 85.12% and a Kappa index of 0.81. Finally, we used landscape metrics and diversity indices derived from AFS mapping and the tree species inventory to analyze the diversity of the studied AFS located in the Senegalese Peanut Basin. The results of the analysis evidenced the compositional, configurational and functional heterogeneity found in the study area. This allowed us to demonstrate the ability of the sampling strategy proposed in this paper to capture the various types of heterogeneity in agricultural landscapes. We also showed by implementing the method that it can be used for (i) tree biodiversity analysis, (ii) mapping and (iii) characterization of a complex AFS in sub-Saharan Africa.

Performance of dry and wet spells combined with remote sensing indicators for crop yield prediction in Senegal

Studying the relationship between potential high-impact precipitation and crop yields can help us understand the impact of the intensification of the hydrological cycle on agricultural production. The objective of this study is to analyse the contribution of intra seasonal rainfall indicators, namely dry and wet spells, for predicting millet yields at regional scale in Senegal using multiple linear regression. Using dry and wet spells with traditional indicators i.e. proxies of crop biomass and cumulated rainfall, hereafter called remote sensing indicators (NDVI, SPI3, WSI and RG), we analysed the ability of dry and wet spells alone or combined with these remote sensing indicators to provide intraseasonal forecasts covering the period 1991–2010. We analysed all 12 regions producing millet and found that results vary strongly between regions and also during the season, as a function of the dekad of prediction. At the spatial scale, the strongest performing combinations include the dry spell indicators DSC20 and DSxl in the peanut basin. While in the south of the country, the combination of wet period indicators WS1 or WSC5 with the RG is fairly reliable. Focussing on Thies, our best region in the groundnut basin, we showed that dry and wet spells indicators can explain up to 80% of yield variations, alone or in combination with remote sensing indicators. Regarding the timing of prediction, millet yield can be forecast as early as July with an accuracy of 40% of the mean yield but the best forecast is obtained in early September, at the peak of crop development (accuracy of 100 kg/ha i.e. 20% of the mean yield). Although, the estimated yields show biases over some years identified as extremely deficient or in oversupply in terms of agricultural yields.

Climatic variability in the Sine-Saloum basin and its impacts on water resources: case of the Sob and Diohine watersheds in the region of Niakhar

Abstract. Local peoples from Niakhar in the Senegalese peanut basin highlight a dramatic increase of water access problems due to marked rainfall deficits and salinization of surface and ground water resources. The chemical quality of groundwaters is often critical because of the salinization process, whereas water surfaces, which should be used in such situations, are up early. More and more, lowlands and rivers beds are pervaded by salt crusts. Then the salinization of wells is increasing, leading to the extension of tans (salty of acidified soils). To study the impacts of climatic pejoration on the agroecosystems and on the living conditions of the populations, we carried out the analysis of the time series of the precipitations with daily and annual time steps from 1950 to 2015 on 6 meteorological stations, in situ measurements on 78 wells for an area of 311 km2, as well as local population interviews and field observation. The results confirm an important climatic break in the region in 1970. The long dry period, from 1970 to 2009, has increased the annual rain variability, decreased the number of rainy days per year. We confirm a real and large extension of well salinization, and salt crusting in the lowlands and the riverbeds. From the local people, it seems the process of degradation of the aquifers continues to progress from a large tidal event in 1984. The rainfall increase noted in the last decade does not seem to be enough to reverse the trend and to ensure both the rise of the piezometric level of the aquifers and the desalinization of surface and ground waters.

Birds and bats contribute to natural regulation of the millet head miner in tree-crop agroforestry systems

A better understanding of environmental factors driving natural pest regulation is a major challenge for designing sustainable cropping systems. The objective of the present study was to assess the association between vegetation openness in traditional tree-crop agroforestry systems in Senegal, richness and abundance of vertebrates including insectivorous birds and bats, and their contribution to the natural regulation of crop pests. The millet head miner (MHM), Heliocheilus albipunctella (Lepidoptera, Noctuidae), a major constraint to increasing millet crop productivity in sub-Saharan Africa, was selected as a model system. Ten sites separated by at least one km from each other were selected in a 100 km2 study area in the Peanut basin in Senegal. In each site, a pair of millet fields distant from at least 100 m each was selected according to a gradient of vegetation openness within a 100-m radius buffer with sampling plot (5 × 5 m) at the center. Nine insectivorous bird and bat species were recorded in millet fields over the 2017 cropping season and their predator status was confirmed by direct observation or DNA detection in fecal samples. Grain losses were reduced when panicles were accessible to birds and bats, confirming their net contribution to pest regulation. At a local scale, tree diversity and vegetation openness were important predictors of the abundance of insectivorous village weaver birds and grey-headed sparrows, respectively. Some tree species (soapberry trees and neems) indirectly contributed to natural regulation of the MHM likely by providing refuges to insectivorous vertebrates whereas other tree species (baobabs) provided disservices as possible refuges for the MHM moths. Further research is needed to better understand relationships between tree cover, food web interactions and natural pest suppression, so that specific conservation measures such as habitat management can be designed to improve pest control.

Peanut residues supply minimal plant‐available nitrogen on a major soil series in the USA peanut basin

AbstractField observations have shown that a substantial portion of peanut leaves abscise in windrows during pod curing, leading to an uneven distribution of leaves and stems when intact residues are spread during harvest. Possible differences in nitrogen (N) mineralization rates between peanut leaf and stem residues may lead to spatial and temporal variability in available N during subsequent crops. The objective of this study was to quantify N mineralization in soil amended with different peanut residue components under simulated conventional and conservation tillage practices. A 252‐day microlysimeter incubation was conducted in which peanut leaves, stems and a 1:1 mixture of leaves:stems from three varieties were incorporated or placed on the soil surface to simulate conventional or conservation tillage, respectively. Soils were periodically leached to assess N mineralization compared with a soil‐only control. Nitrogen mineralization was only affected by residue component. Averaged over variety and residue placement, soil amended with leaves mineralized 10% more N relative to the control or soil containing stems. It was estimated that leaves supplied 25 kg N ha−1 over 252 days at 0–15 cm soil depth, which would likely be insufficient to induce a yield response by a subsequent crop. This study suggests that uneven distribution of peanut leaf and stem residues following harvest causes only minor spatial and temporal variability in available N during subsequent crop growth. These results support the growing body of evidence indicating that peanut residue N contributions to subsequent crops are negligible in the peanut basin of the south‐eastern USA.

Milk production traits among indigenous and crossbred dairy cattle in Senegal

Milk production and milk composition of various cattle breeds and their crosses in the North Central Peanut Basin of Senegal have been analysed. In total, 6082 records were collected from 1447 cows. But finally, only 1923 test-day records of milk volume were evaluated from 319 cows with 370 lactations during a longitudinal survey. A subset of 227 cows was used to determine the milk composition of the main breed-groups that were present and which were clustered into four groups: Indigenous zebus (Zebu Gobra; Zebu Maure), Indigenous zebu by Guzerat (Indigenous zebu cross with 25% to 50% Guzerat), Indigenous zebu by Bos taurus taurus (Indigenous zebu cross with 25% to 50% Bos taurus taurus where the Bos taurus taurus includes breeds such as Montbeliarde and Holstein-Friesian) and High Bos taurus taurus (cows with a high component of Bos taurus taurus , typically 75% to 100% of previous Bos taurus taurus ). The daily milk yield, cumulative milk yield of 305 days, milk fat and protein percentages were determined for each cluster. The daily milk yield varied from 1.43 L/day in indigenous zebus to 7.04 L/day in High Bos taurus taurus . In general, the daily milk yield increased with the number of parturitions. Indigenous zebus showed the lowest 305-day milk yield (466 L and 496 L for first and later lactations, respectively) whilst High Bos taurus taurus cows showed the highest milk production (1408 L and 2108 L for first and later lactations, respectively). Fat percentage increased from the primiparous to the multiparous cows. Primiparous Indigenous zebus by Bos taurus taurus cows showed the highest fat content (5.10%), followed by Indigenous zebus (4.44%). The average calving interval ranged from 519 days for Indigenous zebus by Bos taurus taurus to 580 days for Indigenous zebus. The average lactation length for all cows was 370 days. Key words : Dairy cows, lactation, milk yield, milk quality, breed differences, Senegal

Soil Characterization and Classification of the Koutango Watershed in the Semi-Arid Southern Peanut Basin of Senegal

Soil Characterization and Classification of the Koutango Watershed in the Semi-Arid Southern Peanut Basin of Senegal

Allometric equations and carbon stocks in tree biomass of Jatropha curcas L. in Senegal’s Peanut Basin

In Senegal, numerous initiatives exist to cultivate Jatropha curcas L. (JCL) trees as a multipurpose energy crop, including for fuel. Thus, research on this drought-resistant shrub has been predominately focused on biofuel production from its seeds, while its potential for carbon (C) sequestration, which could be valuable in sink projects (i.e., afforestation, reforestation) under the Clean Development Mechanism (CDM) of the Kyoto protocol, has been largely unstudied. This study was carried out in Senegal’s Peanut basin to develop allometric equations for estimating biomass of individual JCL shrubs, JCL plantations, and determining their respective C storage potential. We discovered a three-stage evolution of JCL biomass accumulation. A slow build-up stage (1–3 years), followed by a fast production of biomass (3–4 years), and a relatively slower stage where certain fractions-root and leaf biomass-reach a plateau (4–5 years). The ratio between belowground and aboveground biomass varies from 53% (1 year after planting) and 26% (5 year after planting), with an average of 41%. We developed allometric models that provide a reliable estimation of the different biomass fractions of JCL and according to tree age. The models revealed that the stocks of biomass and C become relatively important from the fifth year with a storage capacity of 5.07 kg per tree. Most of the biomass and organic C are stored in the aboveground fractions of trees, suggesting that JCL plantations may be valuable for C sink and CDM projects.

Evaluating Intercropping (Living Cover) and Mulching (Desiccated Cover) Practices for Increasing Millet Yields in Senegal

Located within the Sahel region, Senegal faces several agricultural production challenges. Limited rainfall, poor soil fertility, and insufficient agronomic inputs all contribute to low pearl millet [Pennisetum glaucum (L.) R. Br.] yields. This study was initiated to assess the potential for increasing millet yields through intercropping (living cover) and mulching (desiccated cover) practices. During the 2013 and 2014 growing seasons, pearl millet was intercropped with cowpea [Vigna unguiculata (L.) Walp.], mungbean [Vigna radiata (L.) Wilczek], or grown under mulch (neem [Azadirachta indica] leaves applied at 2 t ha−1). Field trials were conducted at two sites within Senegal's central millet–peanut (Arachis hypogaea L.) basin, in Bambey (14°41′38″ N, 16°28′12″ W) and Thiés (14°45′45″ N, 16°53′14″ W). Soil moisture and plant N (based on the normalized difference vegetation index [NDVI]) were measured in addition to yield. When intercropped with a legume, millet grain yields increased up to 55% compared to millet alone. The combined grain yields under intercropping (millet + legume) were always higher than yields of millet alone, up to 67% in Bambey. Mulching increased soil moisture up to 14%, with yield increases of up to 70% over millet with no mulch. Plant N increased in both intercropped and mulched millet, with NDVI increases up to 21% with mulch and 16% when grown with a legume (prior to flowering). These yield increases were achieved using resources that are available and affordable to small‐scale producers in the region (seeds and mulch), and did not require the addition of fertilizer inputs.Core Ideas Intercropping millet with cowpea or mungbean was found to increase millet grain yield compared to millet that was grown alone. Yield increases as high as 55% were recorded. Increasing ground cover through mulching of millet was found to significantly increase soil moisture compared to millet grown with no additional ground cover. Soil moisture increased up to 14% in mulched soils compared to unmulched soils. Intercropping millet with a legume (cowpea or mungbean) always resulted in a higher combined yield than growing either the millet or the legume by itself.

Calf management practices, challenges and opportunities in traditional cattle production systems in the Peanut Basin of Senegal.

Calf management in traditional cattle herds in many parts of the tropics receive less attention as compared to immediate income-generating cows or bulls. Information on long-term implications of poorly reared young stock is limited. A study to assess practices, challenges and opportunities during rearing of less than 12-month-old calves in traditional cattle herds in the Peanut Basin of Senegal was carried out. Data were collected on 207 farms through farm visits and completion of a questionnaire. Categorical principal component analysis followed by two-step cluster analysis identified two cattle production systems: livestock based (LB: 47.83%) and livestock-crop based (LCB, 52.17%). On average, 2.81 ± 0.15 calves were reared per farm. Calves were weaned at the age of 12.27 ± 0.32months. A majority of the calves were of indigenous breeds (71.37%) and were meant to serve as replacement stock (74.23%). The tropical livestock unit for cattle owned was significantly lower in LB compared to LCB farms (12.71 vs. 18.85). Significantly higher number of farmers owned non-indigenous calves, had clean calf rearing area and reported feed availability in LB farms as compared to LCB farms. A majority of farmers (98.50%) perceived calf morbidity and mortality as a major challenge in calf rearing. Meanwhile, labour was readily available to assist with calf rearing in 88.24% of farms in both systems. Capacity building on improve husbandry practices could enhance calf survival and productivityin surveyed farms. Studies to better identify health and feeding constraints of calves will be necessary to define intervention targets.

A historical political ecology of land use in the southeastern Peanut Basin of Senegal

This article presents a history of twentieth century human occupation and agricultural expansion in the southeastern Peanut Basin in Senegal, West Africa. Using a political ecology conceptual framework, I describe social and cultural characteristics of the region’s population relevant to an analysis of environmental challenges that have affected the region over time. I also address the significance of state intervention, during both colonial and post-colonial times, in agricultural resettlement schemes that were intended to control access to land-based resources in this less densely populated part of the country. A discussion of more recent studies on environmental change and land use in the Peanut Basin illustrates the importance of understanding the region’s past in order to address its contemporary environmental challenges. This examination of historical land use dynamics in the southeastern Peanut Basin informs current conditions and future concerns regarding natural resource management in the region.

Analysis of vegetation seasonality in Sahelian environments using MODIS LAI, in association with land cover and rainfall

Present-day Sahelian vegetation in a highly anthropized semi-arid region is assessed from local to regional scales, through the joint analysis of MODIS LAI (1km2 and 8-day resolutions), daily rainfall, morphopedological and land cover datasets covering the period 2000–2008. The study area is located in northwest Senegal and consists of the “Niayes” and the northwestern “Peanut Basin” eco-regions, characterized by market gardening and rain-fed cultivated crops, respectively. The objectives are i) to analyse at pixel scale LAI time series and their relation to vegetation and soil types, ii) the estimation of phenological metrics (start of season SOS, end of season EOS, growing season length GSL) and their inter-annual variability, iii) to recognize the vegetation responses to rainfall trends (mean annual precipitation, MAP; frequency of rainy events, K; combination of MAP and K, called F).Pixel-scale analyses show that LAI time series 1) describe the actual phenology (agreeing with ground-truth AGHRYMET data), and thus can be used as a proxy for Sahelian vegetation dynamics, 2) are strongly dependent on soil types. Median maps of SOS and EOS suggest an increase of the GSL from Saint-Louis to Dakar, in agreement with both the North-South rainfall gradient and the intensification of agricultural practices around Dakar. Significant correlations (R: 0.64) between annual variation coefficient of LAI and MAP for both herbaceous crops and natural vegetation are highlighted; this correlation is reinforced (R: 0.7) using the rainfall distribution factors K and F. Rainfall thresholds allowing the SOS can be defined for each type of vegetation. These thresholds are estimated at 0–5mm, 20mm and 40mm for natural herbs, herbaceous crops and shrublands, respectively.If previous works revealed the close link between the MAP and the SOS, our results highlight that LAI dynamics are also controlled by rainfall distribution during the Monsoon season. In this study, climatic indicators are proposed for estimating vegetation dynamics and monitoring SOS. Coupling Earth Observation data, such as MODIS LAI, with rainfall data, vegetation and soil information is found to be a reliable method for vegetation monitoring and for assessing the impact of human pressure on vegetation degradation.