Development of a Training Knowledge Management System for the SERVIR Global Network

No abstract availabl

Genetic diversity of rhizobia and plant growth promoting rhizobacteria of soil under the influence of Piliostigma reticulatum (DC.) Hochst and their impact on shrub growth

International audiencePiliostigma reticulatum shrub is a native legume found in fallow areas in dry and semi-dry savanna soil and is used in intercropping systems. The aim was to understand the functioning of the rhizosphere, particularly the involvement of symbiotic and free living-N fixing bacteria. Soil extracts collected from P. reticulatum roots were sampled in two contrasting areas and endophytic bacterial communities were isolated using three trap host species (F. albida, A. bivenosa and V. seyal). Potential endophytic bacteria (PEB) were characterized by RFLP, nifH PCR and by 16S rRNA gene sequencing. The subsequent behavior of P. reticulatum was monitored in vitro by measuring leaf weight, biomass and chlorophyll content, after inoculation with PEB. This approach enabled isolation of 59 bacteria belonging to different genotypes. The most abundant genera were Cohnella (27.65%) among which 11 isolates clustered together and could represent a new species closely related to C. plantaginis. The other dominant genera were Paenibacillus (21.27%), Bradyrhizobium (14.89%) and Ensifer (8.5%). The nitrogen fixing gene (nifH) was detected in 21 strains and in particular, detected in a single isolate (PZS_S04) close to Cohnella xylanilytica. The strains PZS_S05 (Ensifer) and PZG_A18 (Cohnella) significantly increased certain parameters including shoot dry weight, shrub height at 90 days and photosynthetic activity (SPAD), compared to non-inoculated controls.The result obtained showed that soil under the influence of P. reticulatum roots harbored a specific diversity of endophytic bacteria including two free living-N fixing bacteria with the potential to improve the growth of P. reticulatum in natural conditions

Effect of Soil Collected under Eucalyptus camaldulensis Dehn on Peanut (Arachis hypogaea L.) Development and Soil Microbial Community Structure

Aims: The objective of this study was to determine the effect of soil sampled under E. camaldulensis on peanut development and microbial community. Place and Duration of Study: Soil sampling at the 0-10 cm horizon was conducted at different distances: 1.5 m, 3 m, 4.5 m, 6 m and 30 m from 3 randomly selected E. camaldulensis plants in four sites: Karamba, Nicia, Rokout and Dioncome. Methodology: A two-factor randomized complete block design was set up in a greenhouse experiment and parameters such as chlorophyll content, acetylene reducing activity, mycorrhization rate, number of nodules, mass of dry matter and microbial community structure were studied. Results: No significant difference was noted among the parameters regardless of the sampling distance for the Karamba, Nicia and Dioncome sites (P>0.05). In the case of Rokout site, however, the chlorophyll content measured at 4.5 m was significantly different from the chlorophyll content measured at 1.5 m from the tree. For aboveground dry biomass, no significant difference was noted regardless of sampling distance at Karamba and Rokout sites except for samples collected at 4.5 m (Pa≤0, 045; Pc≤0.029). No significant difference was also noted for root biomass regardless of sampling distance at the Karamba, Rokout, and Dioncome sites (P>0.05). However, at Nicia, the biomass of the control treatment was significantly higher compared to others (P=0.021). Nodulation did not vary according to sampling distance (P>0.05). The amount of nitrogen fixed is higher at 6 m from Eucalyptus compared to other distances at the Karamba and Nicia sites (P<0.02). In contrast, at Boucotte it is higher at 1.5 m from the tree (P<0.03). Mycorrhization intensity was significantly higher at 6 m and 30 m from the tree compared to other distances. Conclusion: Microbial community structure differed between soil collected under and outside of the canopy of E. camaldulensis

An Investigation into the Effects of Organic Amendments in a Saline Environment on Soil Chemical Characteristics, Growth, and Yield of Rice in the South of Senegal

Context of the Study: The use of organic amendments could help increase the resilience of lowland rice in Lower Casamance to salinity. The aim of this study was to test the effect of different organic amendments (biochar and compost) on the salinity tolerance of lowland rice in Basse Casamance. Objective: The aim was to test the effect of different organic amendments on the salinity tolerance of rice in the lowlands of the villages of Selecky and Essyl in Lower Casamance. Methodology: A split-plot design was adopted with two factors: the type of organic amendment with 4 treatments (biochar, compost, compost + biochar and the control) and salinity with two treatments (salted and unsalted zones). These treatments were repeated 3 times in two consecutive years, 2020 and 2021, at the Selecky and Essyl sites. Physico-chemical characteristics as well as rice growth and production parameters were studied. Results: In the saline zone, soil amendments significantly increased the number of tillers and the height of rice plants compared with controls (p<0.05). Average rice yield and plant biomass were significantly higher in the amended plots at Selecky in both experimental years (p<0.05). At Essyl, on the other hand, height, number of tillers, rice yield and plant biomass were lower in the 2nd year of experimentation. Organic amendments had a significant effect (p<0.05) on rice production and yield parameters in the salt zone

The use of green macroalgae (<em>Ulva lactuca</em> and <em>Codium tomentosum</em>) that have a high methane potential, as a source of biogas in Senegal

International audienceAnaerobic digestion is a biochemical process that occurs naturally in the absence of oxygen. It is used commonly in developing countries to produce both energy and biofertilizers. Objective: The purpose of this work was to study the anaerobic digestion of green macroalgae (Ulva lactuca and Codium tomentosum), which cause severe environmental problems in Dakar-Senegal, and elsewhere along Africa's Atlantic coast. Methodology and Results: These green macroalgae were characterized in terms of physicochemical properties and biochemical methane potential (BMP). Their characteristics were compared to those of other locally available feedstock, such as cow manure and Jatropha curcas cake. The results showed that volatile solids of macroalgae were about 500 g VS/kg and twice that of cow manure. Furthermore, the methane potential of macroalgae was twice (216.4 L CH4/kg VS) that of cow manure (100.3 L CH4/kg VS). The green macroalgae achieved a heating value potential of 2151 kWh/t VS. The methane potential of Jatropha cake as a substrate for anaerobic digestion was intermediate (133.6 L CH4/kg VS) but contained a large quantity of lignin (34%), a slowly biodegradable organic substance. Conclusions and application of findings: This study results showed that green macroalgae could be used as a substrate for the production of renewable energy the biogas in Senegal

The use of green macroalgae (Ulva lactuca and Codium tomentosum) that have a high methane potential, as a source of biogas in Senegal

Anaerobic digestion is a biochemical process that occurs naturally in the  absence of oxygen. It is used commonly in developing countries to produce both energy and biofertilizers.Objective: The purpose of this work was to study the anaerobic digestion of green macroalgae (Ulva lactuca and Codium tomentosum), which cause severe environmental problems in Dakar-Senegal, and elsewherealong Africa's Atlantic coast.Methodology and Results: These green macroalgae were characterized in terms of physicochemical properties and biochemical methane potential (BMP). Their characteristics were compared to those of other locally available feedstock, such as cow manure and Jatropha curcas cake. The results showed that volatile solids of macroalgae were about 500 g VS/kg and twice that of cow manure. Furthermore, the methane potential ofmacroalgae was twice (216.4 L CH4/kg VS) that of cow manure (100.3 L CH4/kg VS). The green macroalgae achieved a heating value potential of 2151 kWh/t VS. The methane potential of Jatropha cake as a substrate foranaerobic digestion was intermediate (133.6 L CH4/kg VS) but contained a large quantity of lignin (34%), a slowly biodegradable organic substance.Conclusions and application of findings: This study results showed that green macroalgae could be used as a substrate for the production of renewable energy the biogas in Senegal.Keywords: Biogas, renewable energy, biochemical methane potential, macroalgae, Jatropha curcas