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Globally, the productivity of sugarcane is highly sensitive to water availability, which is also affected by climate variability. In Ethiopia, Awash River Basin has large-scale sugarcane production using a surface water source. However, there is a lack of integrated basin-scale assessments linking sugarcane growth with water availability under climate change remains a key gap for sustainable water management. This research investigates the dynamics of sugarcane production and irrigation water availability using the Soil and Water Assessment Tool (SWAT+) at Wonji using the CMIP6 climate projections and socio-economic pathways (SSP2-4.5 and SSP5-8.5). This method implements irrigation from channels and Koka reservoir releases to assess projected sugarcane yield, irrigation withdrawal, and water productivity. The SWAT+ model performed well in replicating both sugarcane yield and irrigation use, with a PBIAS (Percent Bias) of 3.5 This figure summarizes the study, which investigates the role of the SWAT+ modeling framework in simulating sugarcane productivity and irrigation demand, both historical and future projections. Daily climate data from the Ethiopian Meteorological Institute (EMI) for precipitation, maximum and minimum temperatures, solar radiation, wind speed, and relative humidity were used in the historical simulation. The dataset from six selected CMIP6 models (Coupled Model Intercomparison Project Phase 6) was applied to project climate change impacts, considering the socio-economic pathways (SSP2-4.5 and SSP5-8.5) scenarios. The framework integrates geospatial data on landuse, topography, and soil types as model input, while observed stream flow and sugarcane yield data are used in model calibration processes. Decision tables were developed to implement management scenarios, including the Koka reservoir release rule, sugarcane planting and harvesting, and furrow irrigation. Linking irrigation from channels is achieved through the water allocation file. Once the SWAT+ model is calibrated and validated for streamflow, sugarcane yield, and irrigation use, the framework was applied to assess future climate impacts by projecting changes in sugarcane yield, water productivity, and irrigation demand. The results show that both projected sugarcane yield and water productivity indicate a decline in both scenarios, with a higher decline in the far future. The irrigation demand is projected to increase, especially in the far future of the high-emission scenario. This integrated approach allows for a thorough evaluation of the impacts of climate change on large-scale irrigated sugarcane systems. Furthermore, it facilitates informed decision-making regarding water allocation and designing adaptation strategies, including adjusting planting and harvesting dates, optimizing reservoir operations, implementing efficient irrigation methods, and utilizing heat-tolerant varieties of sugarcane. The SWAT+ model effectively simulates sugarcane yield and irrigation water usage. Irrigation withdrawals from channels provide valuable guidance for water allocation and management. Projected sugarcane yield and water productivity are expected to decline under both SSP2-4.5 and SSP5-8.5 scenarios. The demand for irrigation water for sugarcane is projected to increase under both climate scenarios. The unmet irrigation demand for sugarcane under both scenarios indicates the need for an additional water source.
A strong Community of Practice (CoP) can be powerful in supporting people to share, generate, and disseminate knowledge. This study evaluates the use of the Communities of Practice (CoP) approach for effective knowledge consolidation in the field of citizen science. Our paper offers an analysis of four CoPs that were set up as part of the European-based 3-year WeObserve project, with distinct themes of (1) co-design citizen engagement; (2) impact and value for governance; (3) interoperability and standards; and (4) the United Nations Sustainable Development Goals. Participation across the four CoPs fluctuated during their three-year life-time. Three key outcomes emerged from the CoPs. First, a joint identity and understanding were created within and across CoPs through the creation of an inception report by each CoP and through the creation of Citizen observatory (CO) vocabulary, which also served to differentiate such observatories from citizen science (CS) initiatives. Next, scientific papers and technical reports were cooperatively produced by CoP members that represent a synthesis of CoP members’ knowledge. Essential ingredients to the success of these CoPs also included extensive stakeholder engagement and the CoPs being steered by the underpinning values of the CS community. The impacts of the WeObserve CoPs range from the uptake of jointly produced publications, novel cooperative CS projects, new CoPs, joint grant proposals, and the integration of citizen science data into SDG monitoring. This evaluation highlights the diverse and transformative potential of CoPs for citizen science practice.
Global nitrogen cycling is tightly governed by iron and sulfur biogeochemical processes in anoxic environments, while the mechanism of surface vacancy structures of iron sulfides in nitrate transformation remains unclear. Here we show that pyrrhotite with iron vacancies and a low Fe–S bond energy (1.35 eV) facilitates efficient electron transfer and microbial utilization of reduced sulfur to convert nitrate into dinitrogen. Conversely, FeS2, with strong Fe–S bonding (1.63 eV), shows minimal reactivity due to restricted electron mobility. FeS, with an intermediate bond energy (1.39 eV) and abundant sulfur vacancies, supports simultaneous abiotic nitrate-to-ammonium and microbial nitrate-to-dinitrogen conversions. These mineral-specific mechanisms regulate nitrogen transformations in anoxic systems such as wetlands and marine sediments, ultimately shaping global nitrogen cycling. Furthermore, tuning iron sulfide phases and vacancy structures offers potential strategies for sustainable wastewater treatment, steering nitrate removal towards nutrient recovery or benign dinitrogen production. Iron–sulfur minerals play critical roles in regulating nitrogen cycling under anoxic conditions. This study shows that pyrrhotite with abundant iron vacancies promotes electron transfer and microbial nitrate reduction to dinitrogen.
The water-energy-food-ecosystems (WEFE) nexus promotes holistic management of natural resources. WEFE sectors are linked through socio-economic connections, for example the food sector depends on water availability, and through policies largely developed in silos. South Africa has c. 80% of households reporting inadequate access to food and water resources, but has mineral wealth supported by high-value agriculture and tourism. The primary energy source is coal, with aging infrastructure leading to intermittent energy supply. This paper presents the development of a system dynamics WEFE nexus model in the Inkomati-Usuthu Water Management Area, capturing interactions between sectors to 2050 under climate and socio-economic pathways. The model integrates policies to assess their impact across sectors. Implemented one-at-a-time, policy impacts tend to be confined to the sector to which they are developed. The land sector is a key nexus impact driver, and land-based policies have wide impacts across sectors. Food production is shown to drop up to 52% compared to the reference, with nitrogen leaching dropping by up to 37%. With all policies implemented simultaneously, impacts across sectors are greater and most sectors benefit for example crop production is enhanced by up to three times, nitrogen leaching drops by up to 48%, and greenhouse gas emissions are reduced by up to 19%, reflecting policy design. By integrating multiple uncertainties, in terms of modelling biases and strong radiative forcing, variables such as crop yield and biomass growth under some RCP8.5 simulations can expand with predicted values well above feasible levels. Results trends were validated by local stakeholders and against observation. Results suggest that interactions between policies are very complex, an important message for policy makers dealing with natural resources management. Results show unintended consequences (trade-offs) of siloed policy development and implementation, with some policies countering the effects of others. For example, land and ecosystems preservation policies tend to reduce local food production, an issue for food security concerns. There are hundreds of millions of combinations, opening opportunities for machine learning to search vast spaces and suggest ‘optimal’ policy strategies. This work contributes to: i) improved understanding of multi-sectoral response to policy implementation; ii) providing updates to policy makers regarding resource response to policy actions; and iii) promoting holistic, integrated thinking about natural resources management and policy development in the region.
Ram pumps, despite serving as off-grid and fossil-free water pumping devices, suffer from significant noise and vibration during operation, adversely impacting both their performance and reliability. The solution proposed in this paper leverages phononic crystals (PCs) concept on the basis of a four-equation fluid-structure interaction (FSI) model to describe and reduce these disturbances. Bloch-Floquet approach has been used to design a PC-based drive pipe consisting of alternating materials, featuring band gaps in the vibrational frequency ranges. The ability of the proposed solution in attenuating noise and vibration and enhancing ram pump performance has been experimentally verified using a hydraulic ram experimental setup. The results show that a drive pipe, constructed with alternating (PVC) and copper pipe sections arranged in 6-unit cells, achieves a 90 % reduction of vibration amplitudes in the pressure signal, leading to a 25 % improvement in the ram pump efficiency compared to the ordinary one operating under identical conditions.
