The water-energy-food nexus is promoted as a new approach for research and policy-making. But what does the nexus mean in practice and what kinds of benefits does it bring? In this article we share our experiences with using a nexus approach in Cambodia’s Tonle Sap Lake area. We conclude that water, energy and food security are very closely linked, both in the Tonle Sap and in the transboundary Mekong River Basin generally. The current drive for large-scale hydropower threatens water and food security at both local and national scales. Hence, the nexus provides a relevant starting point for promoting sustainable development in the Mekong. We also identify and discuss two parallel dimensions for the nexus, with one focusing on research and analysis and the other on integrated planning and cross-sectoral collaboration. In our study, the nexus approach was particularly useful in facilitating collaboration and stakeholder engagement. This was because the nexus approach clearly defines the main themes included in the process, and at the same time widens the discussion from mere water resource management into the broader aspects of water, energy and food security.

Climate change will not only affect crop biomass production but also crop quality. While increasing atmospheric CO2 concentrations are known to enhance photosynthesis and biomass production, effects on the chemical composition of plants are less well known. This is particularly true for major crop plants with respect to harvestable yield quality. Moreover, it remains open, how these effects on quality may be realized under field conditions and how management (e.g. plant N nutrition) or environmental factors (e.g. water availability) will alter impacts of elevated CO2. Here we report on a series of free air CO2 enrichment (FACE) experiments with wheat and barley and with maize in which effects of elevated CO2 combined with different levels of N supply (wheat and barley) and with drought stress (maize) on grain and biomass quality characteristics were investigated. Winter wheat and winter barley (1st experiment) and maize (2nd experiment) were grown in the field each for two growing seasons under ambient and elevated CO2 concentration (FACE, 550μmol mol-1). Wheat and barley were grown under adequate N supply and under 50% of adequate N as sub-treatments. In the maize experiment rain shelters were used to create two different levels of plant water supply (well-watered and drought stress – about 50% of well-watered) as sub-treatments. Treatment effects on elemental composition and a variety of quality characteristics of the plant material at final harvest were investigated. This included a detailed analysis of wheat grain protein components and of different fiber fractions of maize. Compiled results of the relative effects of elevated CO2, N and drought stress treatments on different quality parameters of the crops are presented.

Contaminants of emerging concern present in domestic waste streams include a highly diverse group of potentially biologically active compounds that can be detected at trace levels in wastewater. Concerns about potential uptake into crops arise when reclaimed water is used in food crop production. The present study investigated how 9 contaminants of emerging concern in reclaimed water are taken up into edible portions of two food crops. Two flame retardant chemicals, tris(1‐chloro‐2‐propyl) phosphate (TCPP) and tris(2‐chloroethyl) phosphate (TCEP) and several polar pharmaceuticals (carbamazepine, diphenhydramine, sulfamethoxazole, and trimethoprim) accumulated in a linear, concentration‐dependent manner in lettuce (Lactuca sativa) irrigated with reclaimed water, suggesting passive uptake of both neutral and ionizable chemical contaminants in lettuce. Furthermore, concentration‐dependent accumulation of TCEP and TCPP from reclaimed water was also observed in strawberry fruits (Fragaria ananassa). Collectively, these data suggest that highly polar or charged contaminants can be taken up by crops from water bearing contaminants of emerging concern and can be accumulated in the edible portions. Using these data, however, estimates of human exposure to these contaminants from reclaimed water food crop accumulation suggest that exposure to the contaminants of emerging concern examined in the present study is likely substantially lower than current exposure guidelines. Environ Toxicol Chem 2015;34:2213–2221. © 2015 SETAC

This study aims to evaluate the performance of groundwater-based tube well irrigation systems of Sarlahi District in Nepal considering a water–energy–food nexus approach. The deep tube well (DTW) irrigation systems showed better performance over shallow tube well (STW) irrigation systems in terms of water supply and agricultural output per unit of irrigated area. On the other hand, the STW-based irrigation systems showed better performance in terms of energy use, management operation and maintenance (MOM) cost and benefit–cost ratio compared to DTW-irrigated systems. The productivity of irrigation water and energy input to major crops showed the best performance for maize followed by rice and wheat. The simulated yields of cereal crops through the AquaCrop model showed significant scope for enhancing crop yields and associated benefits through judicious use of water and fertilizer. (Résumé d’auteur)

This review article demonstrates fundamentals regarding the manufacturing of multilayer oil-in-water (M-O/W) emulsions and factors affecting stability of these systems. Moreover, characteristics of major bioactive lipophilic components and ingredients mostly applied to form multilayered membranes as well analytical methods used to examine properties of M-O/W emulsions are specified. It has been shown that production of M-O/W systems is based on the layer-by-layer (LbL) electrostatic deposition technique which makes use of the electrostatic attraction of oppositely charged surfactants and biopolymers to form multicomposite protective layers around emulsion droplets. Finally, limitations regarding studies of M-O/W systems which should be developed are specified.

This study sets out to measure CWU (litre/kg ECM, energy-corrected milk) of typical milk production systems in 60 dairy regions from 49 countries representing 85% of the world׳s milk production. The extended version of TIPI-CAL 5.2 including water model was used for data analysis.The results have shown the CWU/kg ECM ranged between 739L on the Danish farm to 5622 l on the Ugandan farm with a global average of 1833L. When looking at averages per region, the CWU was lowest in Europe (913L) and highest in Africa (3384L) with large intra- and inter-regional differences. Compared with grazing and intensive production system, low yielding cows on small-scale farms have the highest CWU/kg ECM. The key driver for variation in CWU/kg ECM is feed, accounting for 94–99% of the total CWU. Increasing milk productivity might be one of the promising ways to reduce CWU/kg ECM. However, this might also lead to the negative impact into water supply systems if this increase is dependent on land irrigation in water scarce areas. The findings of this study showed the need to address the location of the farm, the feed quality, feeding system and milk production intensity simultaneously when aiming at efficient water resource management which would help to contribute food production and livelihood security of dairy farmers worldwide.

Large quantities of water are required to produce the food for a nation, some of which is derived within the country and some associated with imported food commodities. In this study, we consider the spatially explicit potential impact of alternative healthier eating scenarios for the UK on global blue water scarcity using the concept of a water scarcity footprint. The water required to produce the food consumed by the UK was estimated at 52.6Gm3/y of which 93% is from rainfall at the point where it falls and 7% is “blue” water withdrawn from surface and ground water resources. Five alternative healthier diets were considered and the impact on the blue water scarcity footprint was modest (ranging from −3% to +2% compared to baseline). However more significant impacts were projected on the geographical distribution of the blue water scarcity footprint. This study has shown that if current trade patterns continue, policies to promote healthier eating in the UK may contribute to increased blue water scarcity at home and in other parts of the world. The use of virtual water estimates and global datasets of water scarcity can help to understand the potential environmental impacts of alternative diets.

This review article demonstrates fundamentals regarding the manufacturing of multilayer oil-in-water (M-O/W) emulsions and factors affecting stability of these systems. Moreover, characteristics of major bioactive lipophilic components and ingredients mostly applied to form multilayered membranes as well analytical methods used to examine properties of M-O/W emulsions are specified. It has been shown that production of M-O/W systems is based on the layer-by-layer (LbL) electrostatic deposition technique which makes use of the electrostatic attraction of oppositely charged surfactants and biopolymers to form multicomposite protective layers around emulsion droplets. Finally, limitations regarding studies of M-O/W systems which should be developed are specified.

The Water-Energy-Food (WEF) Nexus approach has an opportunity to create sustainable business solutions, especially in the agricultural sector. This report provides a clear understanding of challenges for the most promising and scalable solutions to the interconnected water, energy and food/feed/fiber problems, allowing combined co-optimization. Searching solutions for nexus challenges, a model based assessment of WEF nexus at global scale and a theoretical perspective of integrating economic and ecological objectives are presented. This study explores the opportunities for the global community to develop robust partnerships and cross sector collaboration to foster water security and increase resource use efficiency, particularly in agriculture and food industry, as part of corporate environmental and financial performance goals.

A. Castro et al., 'Quesungual slash mulch agroforestry systems (QSMAS): improving crop water productivity, food security and resource quality in the sub-humid tropics', Centro Internacional de Agricultura Tropical (CIAT), 2015