Introducing sorghum (Sorghum bicolor L. Moench) genotypes into new environments is necessary for expanding the production of food and fuel, but these efforts are complicated by significant genotype × environment interactions that can reduce their effectiveness. This study set out to thoroughly analyze genotype × environment interactions and assess trade-offs between the agronomic performance and the stability of grain and biomass yields of ten contrasting genotypes under Sudano-Sahelian conditions. Experiments were carried out in a randomized complete block design with four replicates. They were conducted from 2013 to 2016 in Bambey, Sinthiou Malem and Nioro du Rip in Senegal. The joint analysis of variance revealed a highly significant effect (p < 0.0001) of genotypes (G), environments (E) and G × E interaction. Most genotypes showed specific adaptations. The best grain yields were obtained by the Nieleni and Fadda hybrids, while the improved varieties IS15401 and SK5912 were best for biomass production. An Additive Main effect and Multiplicative Interaction (AMMI) analysis showed that good grain yields were associated with environments having good soil fertility and good rainfall, while biomass yields were more influenced by the sowing date and rainfall. Similarly, we were able to confirm for our 10 sorghum genotypes that yield stability was generally associated with low performance, except for the Nieleni and Fadda hybrids, which performed well for grain and biomass production regardless of the environment. The Senegalese control genotype, 621B, showed particular susceptibility to growing conditions (soil), but remained very productive (more than 3 tons per hectare) under good agro-pedological conditions. These results lead us to recommend the Fadda and Nieleni hybrids for the entire study region, while 621B can also be recommended, but only for highly specific environments with good soils.

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.

Reference evapotranspiration is a key parameter in hydrological and meteorological studies and used to determine the actual water use rate for various crops. The objectives of this study were to explore trend in the grass-reference evapotranspiration (ETo) through years 1961–2011 and to identify trend in aridity index as an indicator of change in climate in Togo. ETo was calculated using FAO-56 Penman–Monteith method and trends analyses were performed with non-parametric statistics proposed by Mann–Kendall and Sen slope estimator. Results showed that annual ETo varied from 1,440 to 1,690 mm at Lomé, from 1,761 to 1,905 mm at Tabligbo, and from 1,839 to 1,990 mm at Sokode. The Mann–Kendall test revealed significant increase in annual ETo at Tabligbo (Z = 2.89) and Sokode (Z = 2.29). Annual ETo is much more stable at Lomé with non-significant decrease. In Togo, according to the three study sites, the 1961–2011 period annual aridity index varied from 0.26 to 0.99 at Lomé, 0.38 to 0.98 at Tabligbo, and 0.45 to 1.08 at Sokode. The Mann–Kendall test revealed declining trend in the ratio precipitation/ETo which adversely implies an increasing severity of the aridity index at all the sites, prejudicial to rainfed agriculture practiced by about 90% of Togolese crop growers.

Soil nutrient deficiency and rainfall variability impair the production of sorghum (Sorghum bicolor (L). Moench) in Sudano-Sahelian zone. The aim is to study the environmental factors that can determine the effect of fertilizer application on sorghum grain yield and to formulate tailored fertilization strategies according to sorghum varieties (hybrid and open pollinated improved varieties) and environmental context. Field experiments were conducted during the 2015 and 2016 growing seasons in Nioro du Rip and in Sinthiou Malème (Senegal). In a randomized complete block design arranged in a split-plot with four replications, three factors were tested: sorghum genotype (G: Fadda, Faourou, Soumalemba and Soumba with different cycle lengths), environment (E: irrigation and rainfed, different soil types and fertility levels), and fertilization management (M: five different combinations of application dose and application time) including T1 = no fertilizer applied; T2 (recommended practice, 100%) = 150 kg/ha of NPK (15-15-15) at emergence + 50 Kg/ha of urea (46%) at tillering + 50 kg/ha of urea at stem extension; T3 = 50% T2; T4 (100% delay) = 150 kg/ha of NPK +50 kg/ha of urea at stem extension +50 kg/ha of urea at heading ; T5 = 50% T4. Results showed that: (i) in most environments, stressed plants under late application treatments (T4 and T5) recovered biomass once the fertilizer was applied (ii); grain yield with T5 was higher than with T4 under well-watered conditions (sufficient and well distributed rainfall and eventual complementary irrigations) ; (iii) Fadda, a hybrid, responded differently to fertilization than the other varieties only for biomass production, (iv) late fertilizer application treatment (T4) gave higher grain yield than the recommended practice (T2) in the environment with low yield potential, and (v) long cycle duration genotypes benefited better from late fertilization compared to short cycle duration genotypes. This study showed that under Sudano-Sahelian conditions late fertilization of sorghum can be beneficial to grain yield if the rainy season has a slow start, depending on sorghum genotypes (i.e., cycle length), and on the initial N content of the soil.

From adaptation to building effective resilience to climate change is critical for transforming West and Central Africa (WCA) agricultural system. Climate-Smart Agriculture (CSA) is an approach initiated by leading international organizations to ensure food security, increased adaptation to climate change and mitigation. Its application spans from innovative policies, practices, technologies, innovations and financing. However, CSA initiatives lack scientific-based assessment prior to implementation to ensure their effectiveness. To fill this gap, future interventions should not only be assessed using rigorous methodology but should also be built on lessons learned from previous initiatives. Although there are a lot of climate related agricultural initiatives in WCA, most of them have not been analyzed through a CSA lens and criteria to capitalize on their experiences to improve future interventions. In this study we mapped previous climate-related initiatives in WCA, highlighted their gaps and lessons learned to accelerate the implementation of CSA in the region. The study covered 20 countries in WCA: Benin, Burkina Faso, Cameroon, Cape Verde, Central African Republic, Chad, Côte d’Ivoire, Congo, Gabon, Gambia, Ghana, Guinea, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Togo. CSA initiatives were reviewed using a three-steps methodology: (i) national data collection, (ii) regional validation of the national database, (iii) data analysis including spatial mapping. Data was collected from the websites of international, regional and national organizations working in the field of agricultural development in the region. Each initiative was analyzed using a multicriteria analysis based on CSA principles. A total of 1629 CSA related initiatives were identified in WCA. Over 75% of them were in the form of projects/programs with more of a focus on the first CSA pillar (productivity and food security), followed by adaptation. The mitigation pillar is less covered by the initiatives. Animal production, fisheries, access to markets, and energy are poorly included. More than half of these initiatives have already been completed, calling for more new initiatives in the region. Women benefit very little from the implementation of the identified CSA initiatives, despite the substantial role they play in agriculture. CSA initiatives mainly received funding from technical and financial partners and development partners (45%), banks (22%), and international climate financing mechanisms (20%). Most of them were implemented by government institutions (48%) and development partners (23%). In total, more than 600 billion EUR have been disbursed to implement 83 of the 1629 initiatives identified. These initiatives contributed to reclaiming and/or rehabilitating almost 2 million ha of agricultural land in all countries between 2015 and 2025. Future initiatives should ensure the consideration of the three CSA pillars right from their formulation to the implementation. These initiatives should consider investing in mixed production systems like crop-animal-fisheries. Activities should be built around CSA innovation platforms to encourage networking among actors for more sustainability.