The “water machine” of Bengal: a data-driven and policy-supported strategic use of aquifers for irrigation is needed to maximize their benefits
For decades, millions of farmers in Bangladesh have been capturing more water than even the world’s largest dams. They did so simply by irrigating intensively in the summer dry season using water from shallow wells. The ability to use groundwater to irrigate rice paddies during the dry seasons (January to May) helped Bangladesh become food self-sufficient by the 1990s, which was no small feat for one of the most densely populated countries in the world. Researchers proposed that lowering of the groundwater table as a result of intensive irrigation practices in the dry season created conditions for recharge from monsoon rains (June to September), which then replenishes the groundwater (1). On page 1315 of this issue, Shamsudduha et al. (2) present a quantitative analysis of this depletion-replenish process and show that this recharge has indeed been happening at a large scale, in a process they call the Bengal Water Machine (BWM).
Farmers / Policies / Pumps / Irrigated farming / Shallow water / Groundwater table / Groundwater recharge / Aquifers / Water use / Groundwater irrigation
Africa emits the lowest amounts of greenhouse gases (GHGs) into the global GHG budget. However, the continent remains the most vulnerable continent to the effects of climate change. The agricultural sector in Africa is among the most vulnerable sectors to climate change. Also, as a dominant agricultural sector, African agriculture is increasingly contributing to climate change through GHG emissions. Research has so far focused on the effects of GHG emissions on the agricultural and other sectors with very little emphasis on monitoring and quantifying the spatial distribution of GHG emissions from agricultural land in Africa. This study develops a new index: African Agricultural Land Greenhouse Gas Index (AALGGI) that uses scores and specific scale ranges for carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) to map the spatial variations in regional GHG emissions across Africa. The data for the three main GHGs (CO2, CH4, and N20) were downloaded from FAOSTAT. The data were analyzed through the newly developed African Agricultural Land Greenhouse Gas Index (AALGGI). This is an empirical index with scores ranging from 0 to 10, with higher scores indicating higher levels of emissions. The results show that Southern and North African regions have the lowest amounts of agricultural land GHG emissions, with AALGGIs of 3.5 and 4.5, respectively. East Africa records the highest levels of GHG emissions, with an AALGGI of 8 followed by West Africa with an AALGGI of 7.5. With the continental mean or baseline AALGGI being 5.8, East and Middle Africa are above the mean AALGGI. These results underscore the fact that though Africa, in general, is not a heavy emitter of GHGs, African agricultural lands are increasingly emitting more GHGs into the global GHG budget. The low AALGGIs in the more developed parts of Africa such as Southern and North Africa are explained by their domination in other GHG emitting sectors such as industrialization and energy. The high rates of emissions in East Africa and Middle Africa are mainly linked to intensive traditional farming practices/processes and deforestation. These findings underscore the need to further leverage climate change mitigation actions and policy in Africa and most importantly the co-benefits of mitigation and adaptations in the most vulnerable regions.
Time series analysis / Spatial distribution / Vulnerability / Climate change mitigation / Climate change adaptation / Nitrous oxide / Methane emission / Carbon dioxide / Agricultural land / Greenhouse gas emissions
Farmer-led irrigation / Commercialization / Business models / Smallholders / Private sector / Agricultural research for development / Capacity development / Strategies / Scaling up / Innovation / Agricultural value chains
Water scarcity and pollution are major threats for human development in the Middle East and North Africa (MENA) region, and Lebanon is no exception. Wastewater treatment and reuse in agriculture can contribute to addressing the increasing water crisis in the MENA region. However, what is the actual potential of water reuse as a solution for agriculture in Lebanon? This report addresses this question and provides the most comprehensive assessment of water reuse potential up to now. Using geographic information system (GIS) modelling and the best and most recent data available in the country, the report develops a detailed technical assessment of the quantities of treated water available for safe reuse in irrigation, and identifies the wastewater treatment plants that have the highest potential for that purpose. The report also examines the governance barriers that need to be overcome for the water reuse potential to materialize in practice. These barriers include structural shortcomings in the wastewater sector combined with challenges of governance and the lack of a regulatory framework for reuse management. Once the current economic, financial and political crisis in Lebanon eases, addressing these barriers will be key to achieving more and safer water reuse in the country.
Case studies / Financial situation / Economic crises / Non-governmental organizations / Stakeholders / Water authorities / Irrigation systems / Agricultural land / Domestic water / Parameters / Regulations / Water quality / Wells / Water supply / Groundwater / Infrastructure / Irrigation requirements / Water shortage / Water use / Water availability / Water rights / Water governance / Water demand / Supply and demand / Water balance / Water budget / Water management / Water resources / Geographical information systems / Modelling / Databases / Municipal wastewater / Wastewater treatment plants / Analysis / Irrigation water / Water potential / Water reuse
Training / Course Materials and Fact Sheet
Water demand / Water table / Water levels / Water balance / Discharge / Irrigation requirements / Water requirements / Irrigation water / Manuals / Pumps / Solar powered irrigation systems
Suitable MGNREGS [Mahatma Gandhi National Rural Employment Guarantee Scheme] practices and convergence opportunities for regional development priorities: a compendium
Composting / Aquifers / Surface water / Water productivity / Watershed management / Water conservation / Rain water management / Microirrigation / Horticulture / Farming systems / Diversification / Crop management / Water-use efficiency / Water availability / Groundwater / Water resources
Metrics assessment and streamflow modeling under changing climate in a data-scarce heterogeneous region: a case study of the Kabul River Basin
Due to many uncertainties in hydrological data and modeling, the findings are frequently regarded as unreliable, especially in heterogeneous catchments such as the Kabul River Basin (KRB). Besides, statistical methods to assess the performance of the models have also been called into doubt in several studies. We evaluated the performance of the Soil and Water Assessment Tool (SWAT) model by statistical indicators including the Kling-Gupta efficiency (KGE), Nash–Sutcliffe efficiency (NSE), and the coefficient of determination (R2 ) at single and multi-outlets in the KRB and assessed the streamflow under changing climate scenarios i.e., Representative Concentration Pathways (RCP) 4.5 and 8.5 (2020–2045). Because of the heterogeneous nature of the KRB, NSE and R 2 performed poorly at multi-outlets. However, the KGE, as the basic objective function, fared much better at singleoutlet. We conclude that KGE is the most crucial metric for streamflow evaluation in heterogeneous basins. Similarly, the mean and maximum annual streamflow is projected to decrease by 15.2–15.6% and 17.2–41.8% under the RCP 4.5 and 8.5, respectively.
Parameters / Temperature / Land cover / Land use / Soil water content / Watersheds / Case studies / River basins / Climate change / Modelling / Stream flow
Agricultural Water Management (AWM) typologies: targeting land-water management interventions towards improved water productivity
Watershed management / Water conservation / Aquifers / Groundwater / Water security / Water availability / Yield gap / Water productivity / Land / Water management / Agriculture
Chromium (Cr) contamination in paddy soil-rice systems threatens human health through the food chain. This study used a new dataset of 500 paddy soil and plant tissue samples collected in the rice-growing regions of Sindh and Punjab Provinces of Pakistan. Overall, 97.4% of grain samples exceeded the Cr threshold values of 1.0 mg kg-1, determined by the China National Food Standard (CNFS). The Cr in paddy soil, 62.6% samples exceeding the China natural background threshold value (90 mg kg-1) for Cr concentration in paddy soil, and lower than the (pH-dependant gt; 7.5 threshold value for Cr 350 mg kg-1) as determined by China Environmental Quality Standards (EQSs) for paddy soil (GB15618-2018). Geographically weighted regression (GWR) modelling showed spatially nonstationary correlations, confirming the heterogeneous relationship between dependent (rice grain Cr) and independent paddy soil (pH, SOM, and paddy soil Cr) and plant tissue variables (shoot Cr and root Cr) throughout the study area. The GWR model was then used to determine the critical threshold (CT) for the measured Cr concentrations in the paddy soil system. Overall, 38.4% of paddy soil samples exceeding CT values confirm that the paddy soil Cr risk prevails in the study area. Furthermore, the GWR model was applied to assess the loading capacity (LC), the difference between the CT, and the actual concentration of Cr in paddy soil. Loading capacity identified potential paddy soil Cr pollution risk to rice grain and assessed the risk areas. Overall LC% of samples paddy soil Cr risk areas grade: low-risk grade I (34.6%); moderate-risk grade II (15.8%); high-risk grade III (11.2%); and very high-risk grade IV (38.4%) have been assessed in the study area. The human health index, total hazard quotient (THQ 1), indicates no potential health risk originating from Cr exposure to the population. However, the excess Cr level in paddy soil and rice grain is still a concern. The current studyapos;s results are also valuable for the national decision-making process regarding Cr contamination in the paddy soil-rice system.
Modelling / Translocation / Bioaccumulation factor / Physicochemical properties / Metals / Risk assessment / Health hazards / Human health / Rice fields / Paddy soils / Contamination / Chromium
Are climate finance subsidies equitably distributed among farmers? Assessing socio-demographics of solar irrigation in Nepal
Solar-powered irrigation pumps are a vital tool for both climate change adaptation and mitigation. Since most developing countries cannot fully utilize large-scale global funds for climate finance due to limited institutional capacities, small-scale solar irrigation pumps (SIPs) can provide a climate-resilient technological solution. We study the case of a subsidized SIP program in Nepal to understand who likely benefits from a small-scale climate finance program in a developing country setting. We analyze government data on profiles of farmers applying for SIPs and in-depth interviews with different actors along the SIP service chain. We find that vulnerable farmers (women, ethnic minorities, and poor farmers) were less likely than wealthier and non-minority farmers to have access to climate finance subsidies. Even though the government agency gave preference to women and ethnic minority farmers during beneficiary selection, an unrepresentative pool of applicants resulting from social and institutional barriers that prevented them from applying to the program led to an inequitable distribution of subsidized SIPs. The lack of a clear policy framework for allocating climate finance subsidies was a significant constraint. Lack of periodic updating of SIP prices and poor provision of after-sale services were also responsible for the inequitable distribution of subsidized SIPs. We recommend the involvement of local governments in soliciting applications from a wider pool of farmers, periodic revision of SIP prices to reflect market price, replacement of the current fixed subsidy scheme with a variable subsidy scheme, and mandatory provisions of after-sales services.
Monitoring / Policies / Renewable energy / Pumps / Solar powered irrigation systems / Ethnic groups / Social inclusion / Gender / Women farmers / Smallholders / Equity / Subsidies / Finance / Climate change
The projected climate change substantially impacts agricultural productivity and global food security. The cropping system models (CSM) can help estimate the effects of the changing climate on current and future crop production. The current study evaluated the impact of a projected climate change under shared socioeconomic pathways (SSPs) scenarios (SSP2-4.5 and SSP5-8.5) on the grain yield of winter wheat in the North China Plain by adopting the CSM-DSSAT CERES-Wheat model. The model was calibrated and evaluated using observed data of winter wheat experiments from 2015 to 2017 in which nitrogen fertigation was applied to various growth stages of winter wheat. Under the near-term (2021–2040), mid-term (2041–2060), and long-term (2081–2100) SSP2-4.5 and SSP5-8.5 scenarios, the future climate projections were based on five global climate models (GCMs) of the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The GCMs projected an increase in grain yield with increasing temperature and precipitation in the near-term, mid-term, and long-term projections. In the mid-term, 13% more winter wheat grain yield is predicted under 1.3 C, and a 33 mm increase in temperature and precipitation, respectively, compared with the baseline period (1995–2014). The increasing CO2 concentration trends projected an increase in average grain yield from 4 to 6%, 4 to 14%, and 2 to 34% in the near-term, mid-term, and long-term projections, respectively, compared to the baseline. The adaptive strategies were also analyzed, including three irrigation levels (200, 260, and 320 mm), three nitrogen fertilizer rates (275, 330, and 385 kg ha-1 ), and four sowing times (September 13, September 23, October 3, and October 13). An adaptive strategy experiments indicated that sowing winter wheat on October 3 (traditional planting time) and applying 275 kg ha-1 nitrogen fertilizer and 260 mm irrigation water could positively affect the grain yield in the North China Plain. These findings are beneficial in decision making to adopt and implement the best management practices to mitigate future climate change impacts on wheat grain yields.
Socioeconomic development / Fertilizers / Nitrogen / Irrigation water / Precipitation / Temperature / Forecasting / Climate models / Crop modelling / Crop yield / Winter wheat / Carbon dioxide / Climate change adaptation
Despite the progress made in conceptualizing and advocating for secure community-based land and forest tenure rights, there is a critical lacuna in advocacy and policymaking processes pertaining to community-based freshwater tenure rights. Moreover, water tenure as a concept has only recently gained significant traction in global policy circles. This report analyzes national and international legal pathways for recognizing customary forms of community-based freshwater tenure rights held by Indigenous Peoples and Local Communities (IPLCs) in sub-Saharan Africa. It employs a methodological framework and builds on an analysis of community-based water tenure systems that was developed and applied by the Rights and Resources Initiative (RRI) and the Environmental Law Institute (ELI) in the publication Whose Water? A Comparative Analysis of National Laws and Regulations Recognizing Indigenous Peoples’, Afro-Descendants’, and Local Communities’ Water Tenure. Based on the key findings of this analysis, in particular the frequent dependence of IPLCs’ legally recognized customary water tenure rights on their legally recognized land and/or forest rights, this report further analyzes national constitutions, national legislation governing water, land, forests, environmental protection and other related matters, international and national case law, and international and regional human rights laws, to explore how legal frameworks are recognizing and protecting customary water tenure rights across sub-Saharan Africa. The findings and recommendations provide a basis for analyzing the comparative effectiveness and potential drawbacks of these legal pathways for the recognition and protection of customary water tenure and ultimately for future work refining and improving legislation and assessing progress in its implementation and enforcement.
International law / Transboundary waters / Participation / Water user associations / Policies / Constitution / Regional organizations / Government / Sustainable development / Food security / Livelihoods / Women / Gender / Human rights / Water governance / Legal frameworks / Forests / Land rights / Water rights / Rural areas / Local communities / tenure rights / Indigenous peoplesapos / Freshwater / Nexus approaches / Water resources / Land tenure / Customary law / Water law / Legislation / Customary tenure / Water tenure
As groundwater levels steadily decline in India, authorities are concerned about reducing extraction for irrigation purposes without jeopardizing food security. Very low or zero prices for electricity and water in agriculture is partly responsible for overextraction, but charging higher prices is politically not feasible. In this study, we describe the results of a pilot scheme implemented in Punjab, India, where farmers who enrolled were allocated a monthly entitlement of electricity units and compensated for unused electricity. Eight hours of uninterrupted daytime electricity supply were also provided under the scheme instead of the usual mix of daytime and night-time supply. Analyzing data from a cross-sectional farm household survey and instrumenting for enrollment, we find that self-reported hours of irrigation for enrolled farmers were significantly lower than for non-enrolled ones, with no impact on rice yields. We also find a reduction in monthly electricity consumption at electricity-feeder level due to the pilot scheme using the synthetic control method. Our results suggest that the combination of daytime electricity provision and cash incentives for unused electricity has the potential to incentivize farmers to reduce electricity consumption and irrigation hours by at least 7.5% and up to 30% without impacting paddy yields.
Pilot projects / Monsoons / Rice / Groundwater extraction / Farmers / Pricing / Nexus approaches / Irrigation / Energy consumption / Electricity supplies / Agriculture / Incentives / Pumping / Groundwater level
Modeling climate change impact on inflow and hydropower generation of Nangbeto Dam in West Africa using multi-model CORDEX ensemble and ensemble machine learning
Climate change (CC) poses a threat to renewable hydropower, which continues to play a significant role in energy generation in West Africa (WA). Thus, the assessment of the impacts of climate change and climate variability on hydropower generation is critical for dam management. This study develops a framework based on ensemble climate models and ensemble machine learning methods to assess the projected impacts of CC on inflow to the reservoir and hydropower generation at the Nangbeto Hydropower plant in WA. Inflow to reservoir and energy generation for the future (2020–2099) is modeled using climate models output data from Coordinated Regional Downscaling Experiment to produce a publicly accessible hydropower dataset from 1980 to 2099. The bias-adjusted ensemble mean of eleven climate models for representative concentration pathways (RC4.5 and RCP8.5) are used. The added value of this approach is to use fewer input data (temperature and precipitation) while focusing on their lagged effect on inflow and energy. Generally, the model output strongly correlates with the observation (1986–2005) with a Pearson correlation of 0.86 for energy and 0.82 for inflow while the mean absolute error is 2.97% for energy and 9.73% for inflow. The results reveals that both inflow and energy simulated over the future periods (2020–2039, 2040–2059, 2060–2079, and 2080–2099) will decrease relative to the historical period (1986–2005) for both RCPs in the range of (2.5–20.5% and 1–8.5% for inflow and energy, respectively), at annual, monthly and seasonal time scales. Therefore, these results should be considered by decision-makers when assessing the best option for the energy mix development plan.
Energy generation / Forecasting / Datasets / Machine learning / Precipitation / Temperature / Climate variability / Reservoirs / Hydroelectric power generation / Hydropower / River basins / Dams / Modelling / Climate change
Water sources remain the key sources of irrigation in semi-arid regions. However, future climate changes threaten these sources. The study analysed water requirements of two commonly cultivated crops in the dry season in the Ghanaian Savannah regions under baseline and future periods. Crop water requirement (CWR) and crop irrigation requirement (CIR) were lowest in baseline periods and increased in the 2020 s, 2050 s, and 2080 s for RCP 4.5 and RCP 8.5 at all locations. CIR was higher for tomato as compared to onions for most locations. Seasonal changes in the CWR ranged from 2–9, 3–12, and 3–12% and 2–8 3–12% and 5–18% for the 2020 s, 2050 s and 2080 s under RCP 4.5 and RCP 8.5, respectively, for both the crops. Bole and Zuarungu recorded highest increases in CWR for tomato, whereas the least change was observed at Yendi for onions. Changes in seasonal CIR ranged from 3–19, 2–21, and 6–22%, respectively, for the 2020 s, 2050 s and 2080 s for RCP 4.5. Under RCP 8.5, changes in seasonal CIR ranged from 3–23, 5–23, and 6–27% were observed for the 2020 s, 2050 s, and 2080 s, respectively. Highest increases in CIR were noticed at Bole and Zuarungu for tomato, whereas the least change was observed at Wenchi for onions. Findings of the study support zero hunger and climate action, goals 2 and 13 of the SDGs.
Onions / Tomatoes / Forecasting / Rain / Evapotranspiration / Temperature / Dry season / Savannahs / Semiarid zones / Irrigation requirements / Water requirements / Irrigation water / Crops / Climate change
As urbanization increases, meeting the challenges of urban food supply and food security requires coherent and holistic strategies. Attention too often focuses solely on best practices without addressing the required behavior change. This policy brief highlights the importance of minimizing food loss and waste, which accounts for some 30% of current global production, in order to link and achieve SDGs 2, 11 and 12. The strategy comprises four interrelated elements, namely adopting holistic and circular planning perspectives; facilitating urban and peri-urban farming; integrating innovative behavioral interventions; and providing enabling environments. The G20 has the capacity to act rapidly, without the need for major capital investment, thereby also providing leadership to the entire international community.
Policies / Partnerships / Sustainable Development Goals / Strategies / Behavioural changes / Reuse / Waste management / Food supply / Food security / Circular economy / Resilience / Food systems / Peri-urban agriculture / Urban agriculture / Waste reduction / Food losses / Food wastes
Living customary water tenure is the most accepted socio-legal system among the large majority of rural people in sub-Saharan Africa. Based on literature, this report seeks to develop a grounded understanding of the ways in which rural people meet their domestic and productive water needs on homesteads, distant fields or other sites of use, largely outside the ambits of the state. Taking the rural farming or pastoralist community as the unit of analysis, three components are distinguished. The first component deals with the fundamental perceptions of the links between humankind and naturally available water resources as a commons to be shared by all, partially linked to communities’ collective land rights. The second component deals with the sharing of these finite and contested naturally available water resources, especially during dry seasons and droughts. Customary arrangements shape both the ‘sharing in’ of water resources within communities and the ‘sharing out’ with other customary communities or powerful third parties. Since colonial times, communities have been vulnerable to those third parties grabbing water resources and overriding customary uses and governance. The third component deals with infrastructure to store and convey water resources. Since time immemorial, communities have invested in infrastructure for self supply, ranging from micro-scale soil moisture retention techniques to large-scale collective deep wells. As increasingly recognized in both the water, sanitation and hygiene (WASH) and irrigation sectors, this component of self supply is rapidly expanding. In all three components, local diversity is high, with gender, class and other social hierarchies intertwining with social safety nets, neighborliness and moral economies. The study derives two sets of implications for state and non-state policies, laws and interventions. First, state legislation about the sharing of water resources should recognize and protect living customary water tenure, especially through due process in ‘sharing out’ water with powerful third parties. Remarkably, water law, which is dominated by permit systems in sub-Saharan Africa, lags behind other legislation in recognizing customary water tenure (see IWMI Research Report 182). Second, by taking communities’ self supply for multiple uses as a starting point for further water infrastructure development, the WASH, irrigation and other sectors can follow the priorities of communities, including the most vulnerable; identify cost-effective multi-purpose infrastructure; develop local skills; and, hence, contribute more sustainably to achieving more United Nations Sustainable Development Goals (SDGs), in particular SDGs 1, 2, 3, 5, 6 and 13. Further historical and interdisciplinary research to achieve these benefits is recommended.
Nexus approaches / Water security / Land / Livestock / Pastoralists / Farmer-led irrigation / Domestic water / Drinking water / Living standards / Households / Right to food / Right to water / Women / Gender / Costs / Conflicts / Water permits / Water distribution / Water quality / Water governance / Legislation / Policies / Norms / water, sanitation and hygiene / Sustainable Development Goals / Water allocation / Rural communities / Multiple use water services / Water supply / Infrastructure / Water sharing / Water resources / Customary law / Water law / Water management / Water rights / Customary tenure / Water tenure
Climate–urban nexus: a study of vulnerable women in urban areas of KwaZulu-Natal Province, South Africa
The changes in climatic conditions and their associated impacts are contributing to a worsening of existing gender inequalities and a heightening of women’s socioeconomic vulnerabilities in South Africa. Using data collected by research methods inspired by the tradition of participatory appraisals, we systematically discuss the impacts of climate change on marginalized women and the ways in which they are actively responding to climate challenges and building their adaptive capacity and resilience in the urban areas of KwaZulu-Natal, South Africa. We argue that changes in climate have both direct and indirect negative impacts on women’s livelihoods and well-being. Less than one-half (37%) of the women reported implementing locally developed coping mechanisms to minimize the impacts of climate-related events, whereas 63% reported lacking any form of formal safety nets to deploy and reduce the impacts of climate-induced shocks and stresses. The lack of proactive and gender-sensitive local climate change policies and strategies creates socioeconomic and political barriers that limit the meaningful participation of women in issues that affect them and marginalize them in the climate change discourses and decision-making processes, thereby hampering their efforts to adapt and reduce existing vulnerabilities. Thus, we advocate for the creation of an enabling environment to develop and adopt progendered, cost-effective, transformative, and sustainable climate change policies and adaptation strategies that are responsive to the needs of vulnerable groups (women) of people in society. This will serve to build their adaptive capacity and resilience to climate variability and climate change–related risks and hazards.
Socioeconomic aspects / Households / Livelihoods / Communities / Marginalization / Decision making / Gender equality / Gender mainstreaming / Resilience / Coping strategies / Policies / Climate change adaptation / Women / Vulnerability / Nexus approaches / Urban areas / Climate variability
Credit constraint is often considered as one of the key barriers to the adoption of modern agricultural technologies and low agricultural productivity in low- and middle-income countries. Past research and much of the policy discourse associate agricultural credit constraints with supply-side factors, such as limited access to credit sources or high costs of borrowing. However, demand-side factors, such as risk-aversion and financial illiteracy among borrowers could also affect credit-rationing of smallholder agricultural households. This study investigates the nature of credit constraints, factors affecting credit constraint status, and the effects of credit constraints on adoption and intensity of use of three modern agricultural technologies – small-scale irrigation, chemical fertilizer, and improved seeds. The paper also assesses whether credit constraints are gender-differentiated. Primary survey data were collected from sample farmers in Ethiopia and Tanzania, and Tobit and two-step hurdle econometric models were used to analyze these data. Results show that demand-side credit constraints are as important as supply-side factors in conditioning smallholders’ access to credit in both countries. We also find that credit is a binding constraint for the decision to adopt technologies and input use intensity in Tanzania but not statistically significant in Ethiopia. Results suggest that women are more likely to be credit constrained (from both the supply and demand sides) than men in both study countries. Based on these findings, we suggest that policies should focus on addressing both supply- and demand-side credit constraints to credit access, including through targeted interventions to reduce risk, such as crop insurance, and to strengthen the gender sensitivity of credit policies.
Econometric models / Policies / Households / Women / Gender / Access to information / Loans / Social capital / Seeds / Fertilizers / Farm inputs / Technology / Small-scale irrigation / Farmers / Smallholders / Constraints / Agricultural credit / Small-scale farming
Mangroves are a globally important ecosystem that provides a wide range of ecosystem system services, such as carbon capture and storage, coastal protection and fisheries enhancement. Mangroves have significantly reduced in global extent over the last 50 years, primarily as a result of deforestation caused by the expansion of agriculture and aquaculture in coastal environments. However, a limited number of studies have attempted to estimate changes in global mangrove extent, particularly into the 1990s, despite much of the loss in mangrove extent occurring pre-2000. This study has used L-band Synthetic Aperture Radar (SAR) global mosaic datasets from the Japan Aerospace Exploration Agency (JAXA) for 11 epochs from 1996 to 2020 to develop a long-term time-series of global mangrove extent and change. The study used a map-to-image approach to change detection where the baseline map (GMW v2.5) was updated using thresholding and a contextual mangrove change mask. This approach was applied between all image-date pairs producing 10 maps for each epoch, which were summarised to produce the global mangrove time-series. The resulting mangrove extent maps had an estimated accuracy of 87.4% (95th conf. int.: 86.2–88.6%), although the accuracies of the individual gain and loss change classes were lower at 58.1% (52.4–63.9%) and 60.6% (56.1–64.8%), respectively. Sources of error included misregistration in the SAR mosaic datasets, which could only be partially corrected for, but also confusion in fragmented areas of mangroves, such as around aquaculture ponds. Overall, 152,604 km2 (133,996–176,910) of mangroves were identified for 1996, with this decreasing by -5245 km2 (-13,587–1444) resulting in a total extent of 147,359 km2 (127,925–168,895) in 2020, and representing an estimated loss of 3.4% over the 24-year time period. The Global Mangrove Watch Version 3.0 represents the most comprehensive record of global mangrove change achieved to date and is expected to support a wide range of activities, including the ongoing monitoring of the global coastal environment, defining and assessments of progress toward conservation targets, protected area planning and risk assessments of mangrove ecosystems worldwide.
Mapping / Observation / SAR (radar) / Satellite imagery / Landsat / Estimation / Time series analysis / Coastal erosion / Datasets / Ecosystems / Mangroves
Urban development / Cities / Farmland / Land resources / Urban agriculture
Sanitation / Nutrients / Composting / Reuse / Resource recovery / Cost recovery / Business models / Wastewater irrigation / Cities / Farmers / Urban agriculture / Urban wastes
Food security / Behavioural changes / Costs / Food losses / Waste reduction / Food wastes
Spatiotemporal variability of lightning activity over the railway network in Sri Lanka with special attention to the proposed suburban railway electrification network
This study is oriented towards the investigation of the spatiotemporal variability of the lightning activity over the railway network in Sri Lanka using -lightning data from 1998 to 2014 that were downloaded from the database of Lightning Imaging Sensor (LIS) onboard NASA’s Tropical Rainfall Measuring Mission (TRMM). The study has also been extended to study the lightning activity over the proposed suburban railway electrification network. GIS was used to conduct an annual and seasonal analysis of the railway network, which consists of nine major railway lines, to identify vulnerable stations and segments. The average annual lightning flash density over a 1447 km-long railway network of Sri Lanka varies between 5.08–16.58 flashes/(km2 year). The railway lines run across the western and southern regions of the country have been identified as being in areas with higher lightning activity. In comparison to other railway lines, the Kelani Valley line in the Colombo district and Colombo-Maradana to Polgahawela segment of the Mainline are particularly vulnerable to lightning activity. These areas have also been recognized as regions with higher population density. The proposed 102 km long railway electrification network in Sri Lanka is also within higher population density segments, with higher lightning flash density values between 10.55–16.53 flashes/(km2 year). As a result, to improve the operational efficiency of the proposed electrification network, a fully coordinated lightning protection system in accordance with the findings of this study is strongly suggested.
Population density / Vulnerability / Weather hazards / Electrification / Protection / Safety / Transportation / Spatial variation / Railways / Lightning
Capturing spatial variability of factors affecting the water allocation plans—a geo-informatics approach for large irrigation schemes
The livelihoods of poor people living in rural areas of Indus Basin Irrigation System (IBIS) of Pakistan depend largely on irrigated agriculture. Water duties in IBIS are mainly calculated based on crop-specific evapotranspiration. Recent studies show that ignoring the spatial variability of factors affecting the crop water requirements can affect the crop production. The objective of the current study is thus to identify the factors which can affect the water duties in IBIS, map these factors by GIS, and then develop the irrigation response units (IRUs), an area representing the unique combinations of factors affecting the gross irrigation requirements (GIR). The Lower Chenab Canal (LCC) irrigation scheme, the largest irrigation scheme of the IBIS, is selected as a case. Groundwater quality, groundwater levels, soil salinity, soil texture, and crop types are identified as the main factors for IRUs. GIS along with gamma design software GS + was used to delineate the IRUs in the large irrigation scheme. This resulted in a total of 84 IRUs in the large irrigation scheme based on similar biophysical factors. This study provided the empathy of suitable tactics to increase water management and productivity in LCC. It will be conceivable to investigate a whole irrigation canal command in parts (considering the field-level variations) and to give definite tactics for management.
Canals / Irrigation systems / Water quality / Groundwater level / Soil salinity / Soil texture / Cropping patterns / Irrigation water / Remote sensing / Geographical information systems / Geostatistics / Spatial variation / Plans / Water allocation / Irrigation schemes
Solar energy forecasting is considered an essential scientific aspect in supporting efforts to integrate solar energy into power grids. Moreover, solar energy forecasting plays an essential role in mitigating greenhouse gas emissions and conserving energy for future use. This study conducted a bibliometric analysis to assess solar energy forecasting research studies evolution at the continental (Africa) and southern Africa levels. Key aspects of analysis included (i) scientific research trends, (ii) nature of collaboration networks, (iii) co-occurrence of keywords and (iv) emerging themes in solar energy forecasting over the last two decades, between the years 2000–2021. The results indicate that solar energy forecasting research has, on average, expanded by 6.4% and 3.3% in Africa and southern Africa, respectively. Based on the study context, solar energy forecasting research only gained momentum in 2015, peaking in 2019, but it is generally still subtle. The scientific mapping illustrated that only South Africa ranks among the leading countries that have produced high numbers of published documents and also leads in contributions to the research area in both Africa and southern Africa. Three emerging topics were identified from the thematic map analysis— namely, “solar irradiance”, “artificial intelligence” and “clear sky”, which implies that researchers are paying attention to solar irradiance, using modelling techniques that incorporate machine learning techniques. Overall, this study contributes to scientific information on the potential bankability of renewable energy projects that could assist power utilities, governments and policymakers in Africa to enforce the green economy through accelerated decarbonisation of the energy systems and building relationships with developed countries for support and better transitioning to solar energy. From a Water–Energy–Food nexus perspective, the results of this work could assist the scientific community in Africa to take advantage of the inherent interconnectedness of water, energy and food resources, whilst also advancing the use of integrated solutions to shape the focus of solar energy research into a more systems thinking and transdisciplinary approach involving the interconnected primary resources and stakeholders pursuit of the Sustainable Development Goals.
Models / Sustainable Development Goals / Collaboration / Nexus approaches / Foods / Renewable energy / Water / Climate change / Trends / Research / Bibliometric analysis / Forecasting / Solar energy
Determinants of adoption of climate smart agricultural practices among farmers in Bale-Eco Region, Ethiopia
Adoption of climate smart agricultural (CSA) practices has been widely recognized as a promising and successful alternative to minimize the adverse impacts of climate change. However, their adoption among smallholder farmers remains low in developing countries, including Ethiopia. This study examines factors that influence adoption and the level of adoption of multiple CSA practices, including improved agronomy, soil and water conservation, drought tolerant high yielding crop variety, small-scale irrigation, integrated disease, pest, and weed management, and integrated soil fertility management, using survey data from 404 farm households in BaleEco Region (BER), Ethiopia. The study applied a multivariate probit model for analyzing the simultaneous adoptions of multiple CSA practices, and ordered probit model for examining the factors influencing the level of adoption. The CSA practices are found to be complementary. Moreover, farmersapos; adoption of multiple CSA practices, as well as their intensity of adoption, is significantly influenced by the age of the household head, education, land size, household total asset value, frequency of extension contacts, farmer awareness of climate change, farmer experience with climatic shocks, parcel fertility, slope, and severity of soil erosion. The studyapos;s findings suggest that agricultural policy makers and implementers of CSA should recognize the complementarity among CSA practices in order to intensify their adoption among BER farmers and disseminate CSA practices in other parts of the country. Moreover, policymakers should consider household socio-economic, institutional, and parcel-specific factors that positively influence CSA adoption.
Socioeconomic environment / Climate change / Water conservation / Soil fertility / Weed control / Pest control / Integrated disease management / Small-scale irrigation / High yielding varieties / Drought tolerance / Farmers / Smallholders / Agricultural practices / Climate-smart agriculture
This study characterizes the hydrological regime of the Upper Ayeyarwaddy River Basin (UARB) of Myanmar under current and future climate change scenarios by using the Soil and Water Assessment Tool (SWAT). The model simulation results show that the annual precipitation, actual evapotranspiration and water yields are 1,578, 524 and 1,010 mm, respectively. These will increase by 13–28%, 11–24% and 42–198% under two representative concentration pathways (RCPs), RCP 4.5 and RCP 8.5, for the future. There is seasonal variability across the cool, hot and rainy seasons in the agro-ecological regions – mountains, hills and inland plains. As in other Asian regions, the model shows that the wet (rainy) season is becoming wetter and the dry (cool) season is becoming drier in the UARB too.
Plains / Mountains / Agroecological zones / Forecasting / Models / Climatic data / Spatial data / Datasets / Groundwater / Parameters / Evapotranspiration / Water yield / Precipitation / Water balance / Water availability / Climate change / Hydrology / River basins
Achieving climate resilience through improved irrigation water management from farm to basin scale. Editorial
Agriculture / Irrigation systems / Water governance / Water resources / Water productivity / Irrigated farming / Water management / Irrigation water / Resilience / Climate change
The determinants of market participation and its effect on food security of the rural smallholder farmers in Limpopo and Mpumalanga provinces, South Africa
Addressing the disproportionate burden of food insecurity in South Africa requires targeted efforts to help smallholder farmers to access markets. The purpose of this study was to assess determinants of market participation and its contribution to household food security. The secondary data used in this study were collected from 1520 respondents; however, 389 smallholder farmers participated in the market. The Household Food Insecurity Access Scale revealed that out of the total sample size, 85% of the households were food insecure while 15% were food secure. Gender of household head, receiving social grants and higher wealth index positively impacted market participation. Having a family member with HIV had a negative impact on market participation among smallholder farmers. The results from the extended ordered probit regression model showed that household size, having a family member with HIV and agricultural assistance had a positive and significant contribution to the household food insecurity situation of the smallholder farmers. On the other hand, the educational level of household head, ownership of livestock, age of household head, gender of household head, and having access to social grants had a negative and significant effect on the food insecurity status. Access to education and the market can improve household food security. Linking smallholder farmers, particularly women and aged farmers, to markets should form an intrinsic part of the government’s efforts to improve farming and food security and increase access to diversified food.
Probit analysis / Socioeconomic environment / Gender / Agriculture / Food insecurity / Access to information / Rural areas / Farmers / Smallholders / Household food security / Participation / Markets
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