This paper attempts to understand and explore the problem of eutrophication in the context of agriculture with the help of a nexus perspective. Eutrophication is significantly linked to water and energy resources with theoretically well-defined trade-offs and threshold levels. While looking at the linkages between water and land resources comprehensively, our paper questions the present approach to designing and implementing watershed management, and analyses the effects of agricultural intensification, especially in dry regions. Eutrophication is the process by which excessive nutrient loads in water bodies lead to undesirable water-quality problems and the degradation of the overall aquatic ecosystem. Due to limited information and knowledge on water and soil quality in most countries, farmers continue to use fertilizers at an increasing rate and agricultural run-off has been carrying ever more nitrogen and phosphorus into water bodies. This is likely to become a vicious cycle of eutrophication affecting food and water security. Of late, soil- and water-conservation interventions, like watershed development, are further reducing run-off. It is argued that there is a need to rethink the assumptions under which watershed interventions are designed and implemented.

While the world is facing unprecedented transitions and threats we need to deeply rethink the relationships between water and energy use, food production, and ecosystem protection. This includes the development and deployment of ambitious, out‐of‐the‐box solutions towards sustainable development. This paper is based upon recent discussions before and during the 2nd World Irrigation Forum in Chiang Mai, Thailand. This paper takes stock of current knowledge and analyses the most recent trends in water, irrigation and the environment. It discusses the requirements for strategic approaches and the contributions of irrigation and drainage to Sustainable Development Goals. Firstly, we concentrated on renewed and more balanced relationships between water, energy, food and ecosystems in the context of irrigation and drainage management. Secondly, we assessed the positive and negative impact of agricultural water use in order to demonstrate and improve its performance. Given exacerbated competition and water resource scarcity, a better understanding of the positive effects and valuable ecosystem services provided by irrigation and drainage systems could pave the way to maximizing benefits and safeguarding the environment. Lastly, we tried to address the role of stakeholders in irrigation governance. This includes active contribution to policy‐making and planning, incentives, and most importantly, capacity development. Copyright © 2017 John Wiley & Sons, Ltd.

The excessive water use in Central Asian countries has caused an environmental disaster in the Aral Sea. In this regard, they need to improve the efficiency of the use of shared water resources to overcome their environmental and economic difficulties. Accordingly, the twin objectives of this study were firstly to analyse the challenges for the use of water resources in the Aral Sea Basin and secondly to estimate the agricultural water use efficiency according to the crop types and irrigation methods. The results showed that the economic efficiency of water use in Central Asian countries was lower than that of other Asian countries. Finally, this study illustrated that the selection of crop types and irrigation methods can improve the quantitative and economic efficiency of water use. However, a clear preliminary outline of interactions is necessary to avoid failure of coordination and collaboration for a regional win-win approach. In such an outline, this study will deliver valuable information on water efficiency in the Aral Sea basin.

CORE IDEAS: Contributions are mainly from the 2017 International Soil Physics Workshop in China. Soils are fundamental in supplying food, energy, water (FEW), and ecosystem services. Interdisciplinary (convergence) approaches are needed to address FEW challenges. Soils are foundational to sustaining the food, energy, and water (FEW) systems and provide many essential ecosystem services. Soil degradation is a major threat to food security in China and elsewhere in the world. It is critical to advance soil science to improve the FEW systems so that FEW supplies can be provided to human populations in a sustainable and resilient manner. To do so, we must understand interactions among soil physical, chemical, and biological processes, as well as the role, function, and contribution of soil physical processes to delivering FEW supplies and ecosystem services. Soil processes and crop production are strongly controlled by physical processes such as soil water flow, aggregate stability, compaction, heat regime, irrigation and drainage, soil aeration, etc. Recognizing the importance of soil physics to the nexus of FEW systems, the collection in this special section mainly includes research presented at the International Workshop of Soil Physics and the Nexus of Food, Energy, and Water held on 3–5 Aug. 2017 at Shenyang, China. This special section covers diverse topics including fundamental soil physical properties and water flow, land use and agricultural management, soil organic carbon management, soil physical modeling, and transport of emerging contaminants. More future research using interdisciplinary (nexus or convergence) approaches should be undertaken to address challenges in many contemporary and emerging FEW issues.

This paper introduces a modeling framework for the analysis of real and virtual water flows at national scale. The framework has two components: (1) a national water model that simulates agricultural, industrial and municipal water uses, and available water and land resources; and (2) an international virtual water trade model that captures national virtual water exports and imports related to trade in crops and animal products. This National Water, Food & Trade (NWFT) modeling framework is applied to Egypt, a water-poor country and the world's largest importer of wheat. Egypt's food and water gaps and the country's food (virtual water) imports are estimated over a baseline period (1986–2013) and projected up to 2050 based on four scenarios. Egypt's food and water gaps are growing rapidly as a result of steep population growth and limited water resources. The NWFT modeling framework shows the nexus of the population dynamics, water uses for different sectors, and their compounding effects on Egypt's food gap and water self-sufficiency. The sensitivity analysis reveals that for solving Egypt's water and food problem non-water-based solutions like educational, health, and awareness programs aimed at lowering population growth will be an essential addition to the traditional water resources development solution. Both the national and the global models project similar trends of Egypt's food gap. The NWFT modeling framework can be easily adapted to other nations and regions.

This paper attempts to understand and explore the problem of eutrophication in the context of agriculture with the help of a nexus perspective. Eutrophication is significantly linked to water and energy resources with theoretically well-defined trade-offs and threshold levels. While looking at the linkages between water and land resources comprehensively, our paper questions the present approach to designing and implementing watershed management, and analyses the effects of agricultural intensification, especially in dry regions. Eutrophication is the process by which excessive nutrient loads in water bodies lead to undesirable water-quality problems and the degradation of the overall aquatic ecosystem. Due to limited information and knowledge on water and soil quality in most countries, farmers continue to use fertilizers at an increasing rate and agricultural run-off has been carrying ever more nitrogen and phosphorus into water bodies. This is likely to become a vicious cycle of eutrophication affecting food and water security. Of late, soil- and water-conservation interventions, like watershed development, are further reducing run-off. It is argued that there is a need to rethink the assumptions under which watershed interventions are designed and implemented.

Sustainable use and management of nutrients is an important issue for food, energy and water systems. The close connections between the three systems, reflected by the “nexus” concept, warrant an integrated approach to nutrients management across the nexus. In this paper, dynamic modelling of nutrient flows in a local food-energy-water system is presented and applied to a simplified case study. The model was used to simulate several scenarios affecting nitrogen flows and stocks to assess the impact of a) the level of local wheat production, b) the selection of energy generation technology, and c) the management of available nutrient resources (digestate and straws). The simulation results showed that varying the proportion of locally produced wheat significantly affects the surface runoff and the nitrogen content in a local water body, with the latter increasing by nearly 70% in 50 years if about half of the wheat consumed is produced locally as opposed to being 100% imported. The introduction of anaerobic digestion as an energy generation option helps to supply more electricity, reduce the imported fertiliser, and also significantly reduce the landfilled nitrogen nutrient by up to 60 times, due to the reuse of the anaerobic digestate. On the other hand, a balanced consideration should be given between using the straw as fertiliser and as feedstock for energy generation. This work offers a first analysis of the food-energy-water nexus with a focus on nutrient flows and stocks. The modelling approach has the potential to inform holistic decision making with respect to nutrient usage, efficiency and the related environmental impact in the design of a local system for meeting the demand for food, energy and water.

Food production consumes a large amount of water consumption and generates huge amounts of greenhouse gas emissions. Quantitative study of impact food wastage imposing on water and greenhouse gas emissions contributes to public awareness that food wastage will further worsen the resource shortage and climate warming, reducing food wastage accordingly. This paper evaluates the impacts of food wastage in the consumption stage on water resources and the environment in China. The result indicates that in the year 2010, the wastage of major food in China was around 62818 M kg in the consumption link, accounting for 14.5% of the total food production, of which the plant food wastage takes up the majority. The loss of water resources (blue water plus green water) caused by food wastage is 60502 Mm³, more than 10% of the country's total water use. Food wastage has a serious impact on agricultural non-point source pollution and greenhouse gas emissions, resulting in a grey water footprint of 16292 Mm³ and 60.85 M ton of carbon emissions. Taking regional differences of food consumption into consideration, the proportion of water footprints and carbon emissions in the eastern and southern developed areas is relatively higher, while the plant food takes a relatively larger share in water footprints and carbon emissions in the western and central provinces. Reducing food waste is important to remove unnecessary burdens on the environment and natural resources. The optimization of resource utilization in the process of food production is conducive to effectively reduce water footprints and carbon emissions of food; healthy diets shall be popularized among citizens so that the animal food consumption which causes more water footprints and carbon emissions can be decreased, alleviating resource and environmental burdens through reduction of the wastage in food consumption.

This paper attempts to understand and explore the problem of eutrophication in the context of agriculture with the help of a nexus perspective. Eutrophication is significantly linked to water and energy resources with theoretically well-defined trade-offs and threshold levels. While looking at the linkages between water and land resources comprehensively, our paper questions the present approach to designing and implementing watershed management, and analyses the effects of agricultural intensification, especially in dry regions. Eutrophication is the process by which excessive nutrient loads in water bodies lead to undesirable water-quality problems and the degradation of the overall aquatic ecosystem. Due to limited information and knowledge on water and soil quality in most countries, farmers continue to use fertilizers at an increasing rate and agricultural run-off has been carrying ever more nitrogen and phosphorus into water bodies. This is likely to become a vicious cycle of eutrophication affecting food and water security. Of late, soil- and water-conservation interventions, like watershed development, are further reducing run-off. It is argued that there is a need to rethink the assumptions under which watershed interventions are designed and implemented.