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Pluviométrie décadaire des sites de Séfa (SF), de Kolda (KD), de Vélingara (VLG) et de Sinthiou malème (SM) en 2015 et 2016
Source publication
RESUME
Objectif : Déterminer la date et la densité de semis optimales pour une bonne croissance et un maximum de production de grain du mil tardif.
Méthodologie et résultats : L’essai a été installé durant la saison des pluies de 2015 et 2016 en zone soudanienne humide (station de Séfa et Kolda) et en zone soudano sahélienne (station de Vélingara e...
Contexts in source publication
Context 1
... 2015, elle est fixée à la 3 e décade à Kolda, Vélingara et Sinthiou Malème, à la 2 e décade à Séfa. En 2016, cette date est fixée à la 3 e décade à Séfa et à la 1 e décade à Vélingara ( Figure 2). Un démariage de 3 plants a été effectué au 15 e jour après levée (JAL). ...
Citations
... In contrast, for millet, in most Senegal, a local village committee decides the sowing date before the rains start (Grillot, 2018). The exception to this rule is Upper Casamance, where sowing of the local photoperiodic variety of mil sanio is spread out during the months of June and July (Ndiaye et al., 2019;Bamba et al., 2019). ...
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.
... Cela se traduit par des stress hydriques survenant à différents stades de développement des plantes et dommageables pour leur productivité [22], [23]. En effet, la récurrence des pauses pluviométriques surtout observées pendant les phases de croissance et de maturation des graines de nombreuses céréales comme le maïs entraine une baisse de la productivité [24]. Certains travaux ont même montré que les semis tardifs des céréales en conditions de déficit hydrique et de fortes températures en phase de remplissage des grains provoquent une augmentation de la proportion des grains de petite taille et immatures [25], [26]. ...
ABSTRACT: Faced with climatic hazards that lead to the abandonment of some traditional local varieties of maize (Zea mays L.), a study was undertaken in northern Côte d'Ivoire. Its objective was to determine the effectiveness of different manure on the productivity of these local maize varieties under water deficit conditions during the reproductive phase. The experimental device was a split-plot, the first factor of which was fertilizers and the second, variety. A water deficit was observed during the reproductive phase of the maize varieties studied with a higher ETo accumulation than the water available for the plants. The application of chicken droppings and cattle droppings has reduced the development cycle of black seed maize. The depressive effect of water deficit on yield was more pronounced on the control, unlike chicken dropping and cattle dropping manure, which yielded six times more than the control in the black seed variety. As a result, these manures have reduced the depressive effect of water deficit on the yield of this variety. The use of these manures in maize cultivation could be an alternative to the consequences of the water deficit recorded during the reproductive phase in maize. RESUME: Face aux aléas climatiques qui occasionnent l'abandon de certaines variétés traditionnelles locales de maïs (Zea mays L.), une étude a été entreprise au Nord de la Côte d'Ivoire. Elle avait pour objectif de déterminer l'efficacité de différentes fumures sur la productivité de ces variétés locales de maïs en conditions de déficit hydrique au cours de la phase reproductive. Le dispositif expérimental a été un split-plot, dont le premier facteur a été les fertilisants et le second, la variété. Un déficit hydrique a été observé au cours de la phase reproductive des variétés de maïs étudiées avec un cumul de ETo supérieur à l'eau disponible pour les plants. L'application des fientes de poulet et déjections de bovins a réduit le cycle de développement du maïs à grains noirs. L'effet dépressif du déficit hydrique sur le rendement a été plus marqué sur le témoin contrairement aux fumures de fiente de poulet et de déjection de bovins qui ont présenté un rendement six fois plus élevé que le témoin chez la variété à grains noirs. Ces fumures ont donc permis de réduire l'effet dépressif du déficit hydrique sur le rendement de cette variété. L'utilisation de ces fumures en culture du maïs, pourrait constituer une alternative aux conséquences du déficit hydrique enregistré au cours de la phase reproductive chez le maïs. MOTS-CLEFS: Déficit hydrique, évapotranspiration de référence (ETo), évapotranspiration de la culture (ETc), fumure, maïs (Zea mays L.), rendement. Réponse de deux variétés locales de maïs (Zea mays L.) à deux types de fertilisation en conditions de déficit hydrique post-floral en zone soudanienne en Côte d'Ivoire
Impacts potentiels du changement climatique sur les rendements du mil et du sorgho cultivés dans les communes rurales au Niger
Sahelian Africa must meet the challenge of providing enough food to meet its growing population. Therefore, novel breeding and intensive production methods are needed to mitigate this challenge. The objective of this study was to calibrate and validate sorghum varieties leaf area index (LAI) values estimated from Unmanned Aerial Vehicle (UAV) at different growing seasons in Senegal and Mali. To achieve this objective, four experiments were conducted with 14 sorghum (sorghum bicolor) varieties between 2017 and 2019. At the study sites, LAI was measured and crop reflectance was measured with a multispectral camera mounted on a UAV. The study showed that normalized difference vegetation index (NDVI) and simple ratio (SR) were highly correlated to the area index. The results of validation model revealed a better prediction of measured LAI from NDVI (R² = 0.92) and SR (R² = 0.89) vegetation indices in 2019 dry season in Senegal. In addition, the LAI predictions for Mali from NDVI (p < 0.01) and SR (p < 0.01) were highly correlated. Findings showed that vegetation indices can be used to estimate LAI in Mali and Sahel.
Climate change is a major threat to the populations of West Africa in general, and the Sahel in particular. Niger is fully concerned by this situation, which has resulted in high rainfall variability and recurrent droughts since the 1970s. This study analyzes the impact of climate change on millet and sorghum yields in the rural Communes of Balleyara, Dan Issa, Dogo, Harikanassou, Illéla, Magaria and Mokko, Niger. Two millet varieties (HKP and SOMNO) and one sorghum variety (Caudatum) were tested. Climatic data for the reference period 1990-2020 were obtained from the Niger National Meteorology Service and the AGRHYMET Regional Climate Center for West Africa and the Sahel. The SARRA-H (V33) model was used to simulate yields of different varieties over the reference and future periods (2010-2039 and 2040-2069), based on RCP4.5 and 8.5. For each Commune, data for future climate change scenarios were generated by 05 global models chosen from the 29 tested as part of the AgMIP project, considering 05 climatic conditions: Cool and Humid, Cool and Dry, Medium, Hot and Humid, Hot and Dry. Three sowing dates (early, medium, and late), two soil types (sandy and sandy-clay) and two soil fertility levels (Fertile and Non-Fertile) were considered in the SARRA-H model, for each Commune. Simulated yields for millet and sorghum varieties over the period 1990-2020 were higher in the Commune of Magaria and lower in those of Balleyara and Illéla, particularly for late sowing on non-fertile soil. The impacts of future climate scenarios translated into yield reductions for the varieties tested, ranging from -5% to -70% depending on the RCP, horizons, Communes, soil types and sowing dates. The photoperiodic millet variety SOMNO was the least sensitive to the climatic scenarios tested, and the sorghum variety Caudatum the most sensitive. These results show that the choice of varieties and sowing dates best suited to local soil and climate conditions can mitigate the impact of climate change on agricultural yields in Niger, notably through the use of fertilizers and the deployment of measures to reduce the negative impacts of rainfall deficits.
