Changes in Rainfall in Sierra Leone: 1981–2018

Diagnostic Appraisal of the Sorghum Farming System and Breeding Priorities in Sierra Leone

Understanding demographic structures, production constraints, and trait preferences is essential for setting up crop breeding goals and enhancing adoption strategies for new varieties. The objective of this study was to document the sorghum (Sorghum bicolor L. Moench) production constraints and preferred sorghum traits to guide breeding in Sierra Leone. A participatory rural appraisal was used to collect data from 210 farmers across seven districts in Sierra Leone in 2019. Results showed that all sorghum varieties in cultivation are landraces. Poor access to fertilizer (91%), lack of suitable varieties (85%), poor agronomic knowledge (79%), low yielding varieties (78%), storage pests (75%), field pests (67%), low soil fertility (52%), lack of market (49%), sorghum disease (43%), drought (16%), and heavy rainfall (12%) are key production constraints limiting sorghum production. Farmers expressed interest in adopting new varieties with high yield (99%), disease (84%) and pest (81%) resistance, drought tolerance (50%), white grain (59%), and short height (53%). The prioritized traits will form the basis for farmer-oriented sorghum breeding.

A Framework for Calculating Peak Discharge and Flood Inundation in Ungauged Urban Watersheds Using Remotely Sensed Precipitation Data: A Case Study in Freetown, Sierra Leone

As the human population increases, land cover is converted from vegetation to urban development, causing increased runoff from precipitation events. Additional runoff leads to more frequent and more intense floods. In urban areas, these flood events are often catastrophic due to infrastructure built along the riverbank and within the floodplains. Sufficient data allow for flood modeling used to implement proper warning signals and evacuation plans, however, in least developed countries (LDC), the lack of field data for precipitation and river flows makes hydrologic and hydraulic modeling difficult. Within the most recent data revolution, the availability of remotely sensed data for land use/land cover (LULC), flood mapping, and precipitation estimates has increased, however, flood mapping in urban areas of LDC is still limited due to low resolution of remotely sensed data (LULC, soil properties, and terrain), cloud cover, and the lack of field data for model calibration. This study utilizes remotely sensed precipitation, LULC, soil properties, and digital elevation model data to estimate peak discharge and map simulated flood extents of urban rivers in ungauged watersheds for current and future LULC scenarios. A normalized difference vegetation index (NDVI) analysis was proposed to predict a future LULC. Additionally, return period precipitation events were calculated using the theoretical extreme value distribution approach with two remotely sensed precipitation datasets. Three calculation methods for peak discharge (curve number and lag method, curve number and graphical TR-55 method, and the rational equation) were performed and compared to a separate Soil and Water Assessment Tool (SWAT) analysis to determine the method that best represents urban rivers. HEC-RAS was then used to map the simulated flood extents from the peak discharges and ArcGIS helped to determine infrastructure and population affected by the floods. Finally, the simulated flood extents from HEC-RAS were compared to historic flood event points, images of flood events, and global surface water maximum water extent data. This analysis indicates that where field data are absent, remotely sensed monthly precipitation data from Integrated Multi-satellitE Retrievals for GPM (IMERG) where GPM is the Global Precipitation Mission can be used with the curve number and lag method to approximate peak discharges and input into HEC-RAS to represent the simulated flood extents experienced. This work contains a case study for seven urban rivers in Freetown, Sierra Leone.

Can Enhancing Efficiency Promote the Economic Viability of Smallholder Farmers? A Case of Sierra Leone

By developing meta-frontier efficiency and structural equation models, the paper examines whether farm economic viability is positively associated with technical efficiency in a highly food insecure context, such as that of rural Sierra Leone. The findings show that technical efficiency can be a sufficient but not necessary condition in determining economic viability of smallholder farming. It is possible to breach reproductive thresholds at the cost of reduced technical efficiency, when the crop diversification strategy of smallholders includes market-oriented high-value crops. This calls for a dual policy approach that addresses farmers’ internal needs for self-consumption (increasing efficiency of food crop production) while encouraging market-oriented cash crop production (diversification assisted through the reduction of associated transaction costs and the establishment of accessible commercialization channels of export related crops and/or high-value crops). The work also calls out for a move-up or move-out strategy for small holders to create viable farming systems in developing world.