Chemical quality of common beans as influenced by genotype and aluminium rates under two soil liming regimes

Soil acidity affects seed yield and crop quality negatively due to aluminium toxicity in most humid tropics where the crop is cultivated for food and cash income by smallholder farmers. This study was conducted to assess the effect of different exchangeable aluminium concentrations on bean chemical quality of two common bean genotypes grown on lime-treated and lime-untreated soils. Factorial combinations of five aluminium rates (0.0, 12.5, 25.0, 50.0, and 100.0 mg Al/ kg soil) and two common bean genotypes (New BILFA 58 and Roba 1) were laid out in a completely randomized design with three replications. For each treatment, four plants were raised per pot in the vegetation hall of Nekemte Soil Laboratory, western Ethiopia. The experiment was established in two sets: lime-treated soil and lime-untreated soil. The results revealed that aluminium toxicity caused major changes in the composition of the common beans. Significant differences (P < 0.01) were found among the different aluminium rates and between the two genotypes for bean crude protein, crude fibre, crude fat, and ash, carbohydrate, calcium, magnesium, and aluminium contents under both liming regimes. The interaction of aluminium and genotype also influenced most of the bean chemical quality attributes negatively. New BILFA 58 (acidic soil tolerant genotype) had better bean chemical quality attributes (except aluminium and condensed tannins contents) than Roba 1 (acidic soil sensitive genotype) under both liming regimes. On the average, lime application increased bean crude protein, crude fat, ash, and calcium contents by 4.1%, 20.7%, 7.9%, and 11.7%, respectively. However, it decreased bean crude fibre and aluminium contents. Bean carbohydrate and condensed tannin contents of the genotypes increased in response to increasing aluminium application under both liming regimes. The total ash, which is an indirect indicator of the mineral content of foodstuffs, was found to be higher for New BILFA 58 than Roba 1 under both liming regimes. In conclusion, the results of this study have demonstrated that increased soil aluminium contents have significant negative effects on common bean quality, but integrated use of tolerant genotypes and application of lime can simultaneously alleviate the problem of low yield and reduced bean nutritional quality of the crop.Keywords: Aluminium, proximate, Lime, soil, Phaseolusvulgari

Tropical Data: Approach and Methodology as Applied to Trachoma Prevalence Surveys

PURPOSE: Population-based prevalence surveys are essential for decision-making on interventions to achieve trachoma elimination as a public health problem. This paper outlines the methodologies of Tropical Data, which supports work to undertake those surveys. METHODS: Tropical Data is a consortium of partners that supports health ministries worldwide to conduct globally standardised prevalence surveys that conform to World Health Organization recommendations. Founding principles are health ministry ownership, partnership and collaboration, and quality assurance and quality control at every step of the survey process. Support covers survey planning, survey design, training, electronic data collection and fieldwork, and data management, analysis and dissemination. Methods are adapted to meet local context and needs. Customisations, operational research and integration of other diseases into routine trachoma surveys have also been supported. RESULTS: Between 29th February 2016 and 24th April 2023, 3373 trachoma surveys across 50 countries have been supported, resulting in 10,818,502 people being examined for trachoma. CONCLUSION: This health ministry-led, standardised approach, with support from the start to the end of the survey process, has helped all trachoma elimination stakeholders to know where interventions are needed, where interventions can be stopped, and when elimination as a public health problem has been achieved. Flexibility to meet specific country contexts, adaptation to changes in global guidance and adjustments in response to user feedback have facilitated innovation in evidence-based methodologies, and supported health ministries to strive for global disease control targets

Development and evaluation of a framework for global flood hazard mapping

Nowadays, the development of high-resolution flood hazard models have become feasible at continental and global scale, and their application in developing countries and data-scarce regions can be extremely helpful to increase preparedness of population and reduce catastrophic impacts.The present work describes the development of a novel procedure for global flood hazard mapping, based on the most recent advances in large scale flood modelling. We derive a long-term dataset of daily river discharges from the hydrological simulations of the Global Flood Awareness System (GloFAS). Streamflow data is downscaled on a high resolution river network and processed to provide the input for local flood inundation simulations, performed with a two-dimensional hydrodynamic model. All flood-prone areas identified along the river network are then merged to create continental flood hazard maps for different return periods at 30'' resolution. We evaluate the performance of our methodology in several river basins across the globe by comparing simulated flood maps with both official hazard maps and a mosaic of flooded areas detected from satellite images. The evaluation procedure also includes comparisons with the results of other large scale flood models. We further investigate the sensitivity of the flood modelling framework to several parameters and modelling approaches and identify strengths, limitations and possible improvements of the methodology

Streamflow response to climate change in the Greater Horn of Africa

The Greater Horn of Africa region increasingly experiences high risk of water scarcity. A combination of frequent droughts, rapid population growth and rising urbanisation has reduced streamflow and intensified water abstraction, causing water and food shortages. Estimates of future streamflow changes in the region have so far been highly uncertain and evaluations using ground-based measurements are still limited. Here, future streamflow changes are estimated using a distributed hydrological model forced with an ensemble of high-resolution climate simulations produced using the European community Earth-System Model v3.1. The simulated streamflow is evaluated using observed data from 29 stations from river basins across different climate zones in the region. Evaluation results show large sub-regional variations in the performance of simulated streamflow. The sign and magnitude of future streamflow changes vary between climate simulations and river basins, highlighting the uncertainties in the hydrologic projections. Overall, the streamflow projections indicate large (seasonal, long-term mean and extreme) streamflow decreases for all major rivers in Ethiopia and increases in the equatorial parts of the region at the end of the century. The ensemble mean shows a 10 to 25% decrease in the long-term mean flow in Ethiopia and a 10% increase in the equatorial part of the region in 2080s. Similarly, there is a substantial change in high flows in 2080s, with up to − 50% reduction in the northern and 50% increase in the equatorial parts of the region. These findings are critical because the rivers provide water supply to a rapidly changing socio-economy of the region