Food production and consumption have been recognized as a major source of environmental impacts. To ensure food security and a sustainable food system, dietary changes have been identified as one of the valuable strategies to reduce impacts on the environment while promoting human health. The vast majority of scientific literature has been focused on the effects of food consumption on climate change while neglecting to assess the degree of water scarcity impacts due to water consumption embodied in food. The research paper investigates the nexus between food consumption and impacts on water consumption adding important findings to a more recent growing body of studies estimating the water footprint (WF) of different dietary scenarios. This study uses the Water Footprint Network methodology and the AWARE (Available Water REmaining) characterization model to assess both the WF and the blue WSF (water scarcity footprint), respectively, of four Danish diets: standard, carnivore, vegetarian and vegan. In order to make them comparable, a total intake of 2000 kcal person⁻¹ day⁻¹ was set as energetic reference for all the diet scenarios considered. Using detailed trade and production data of agri-foods, we were able to assess the location of primary production and consequently to reveal countries mainly affected by water scarcity associated with import to satisfy Danish diets consumption. We found that while the vegan scenario scored the best environmental profile requiring 1489 L/cap/day calculated with the volumetric WF approach, it has the largest potential impacts on blue WSF of 10,477 LH₂₀₋ₑq/cap/day. This study has shown that more than 90% of impacts on water consumption occur outside the national borders, as a consequence of large quantities of fruits and nuts imported by countries already threatened by high water scarcity conditions such as USA and Mediterranean regions. This methodological approach may be used to compare environmental performances of recommended dietary guidelines and to assess impact scenarios of new trade policies, protecting local water scarcity levels.

Water rights transfer is significantly required for alleviating the ever-intensive water crisis, particularly for arid watersheds with abundant farmland and fossil fuels. However, focusing solely on the re-allocation of water rights and disregarding agricultural water saving potential imperil the security of Water-Energy-Food (WEF) nexus. Furthermore, randomness in water availability leads to water shortage risks and subsequent impact on the whole system. In this study, a risk-based optimization model (RWEF) was proposed to promote inter-sectoral water rights transfer through encouraging energy sector to invest in agricultural water-saving works and get paid back in water rights. Chance-constrained programming is incorporated to analyze the trade-offs between system benefits and water-shortage risks. The developed model was applied to the Inner Mongolia section of the Yellow River Basin, China to verify its effectiveness, considering different development levels of food and energy industries. Results indicated that 488 million m³ of water could be transformed from agriculture to energy, without compromising agricultural production. The main recipients of transferred water rights would be traditional coal-based industries, while it would be difficult for thermal power and most modern coal chemical industries to participate. The construction of water-saving works would help safeguard agricultural production under risks. Compared against two alternative models without water rights transfer mechanism, the average benefit acquired from RWEF under varied water-shortage risks would be at least 68% higher. Particularly, when confronted with extreme water-shortage risk and increased production demands, RWEF would still be able to support agricultural and energy production, while the alternative models being incapable.

The water, energy and food nexus (WEF nexus) is currently quite popular in environmental management. The concept found a fertile ground in science and policymaking, but there is no consistent view on the meaning of integration within the nexus. Here, a wealth of publications is reviewed in an endeavour to: (1) reveal the lines of justification for the need of the WEF nexus debate and (2) identify the range of tools for analysing the interdependent resource issues of the nexus using an integrated framework of science and policy. There are three drivers behind the emergence of the nexus thinking. These are a) increasing resource interlinks due to growing scarcities, b) recent resource supply crises, and c) failures of sector-driven management strategies. Evaluation of the WEF nexus integrative debate can be carried out using four key criteria, namely ability to change current policy debates, issue and thinking novelty, practicability and measurability, and clearness and implementation roadmap. It is clear that, although the nexus has been quite successful in changing policy debates, issue prioritization is missing and seems to be left to specific case studies and policymakers' choices. There is a high need for ‘incorporation’ and ‘cross-linking’ of issues between the three resources. In this regard, nexus governance is the missing link in the nexus debate.

In face of the interdependencies between policy areas in the management of common pool resources, studying nexus challenges is insightful for the exploration of new governance strategies. This includes the co-occurrence of and the interaction between different governance modes. We put forward the argument that a promising approach to explore these dynamics over time is the method of discourse network analysis. By conducting a discourse network analysis of German agricultural and water policy in a region with intensive livestock farming and large surpluses of manure that exert pressure on water and soil resources, we analyse the development of discourses within and across policy areas. We show that the analysis of public discourses contributes to the understanding of coordination between actors.

Food waste is considered a serious global societal problem. How to degrade of food waste in a green and effective way has been to a hot topic. In this work, a method with hot water extraction pretreatment of food waste was investigated and optimized. Under the optimal conditions, more than half of the solid food waste could be transferred to soluble sugars. Meanwhile, in order to improve the tolerance of Rhizopus arrhizus on the food waste hydrolysate, UV combined with chemical mutagenesis were carried out, and a mutant of Rhizopus RH-7-13-807 was obtained. With the mutant strain, the yield of fumaric acid fermented from food waste increased to 1.8 times compared with the original strain, and 23.94 g/L fumaric acid was obtained from the fermentation. Besides, the COD of food waste was evaluated for the degradation of food waste by the Rhizopus RH-7-13-807. The process would decrease the quantity of food waste to be disposed of, and benefit the environment.

In this study, we focus on water quality as a vehicle to illustrate the role that the water, energy, and food (WEF) Nexus perspective may have in promoting ecosystem services in agriculture. The mediation of water quality by terrestrial systems is a key ecosystem service for a range of actors (municipalities, fishers, industries, and energy providers) and is reshaped radically by agricultural activity. To address these impacts, many programs exist to promote improved land-use practices in agriculture; however, where these practices incur a cost or other burden to the farmer, adoption can be low unless some form of incentive is provided (as in a payment for ecosystem services (PES) program). Provision of such incentives can be a challenge to sustain in the long term, if there is not a clear beneficiary or other actor willing to provide them. Successfully closing the loop between impacts and incentives often requires identifying a measurable and valuable service with a clear central beneficiary that is impacted by the summative effects of the diffuse agricultural practices across the landscape. Drawing on cases from our own research, we demonstrate how the WEF Nexus perspective—by integrating non-point-source agricultural problems under well-defined energy issues—can highlight central beneficiaries of improved agricultural practice, where none may have existed otherwise.

In this study, we focus on water quality as a vehicle to illustrate the role that the water, energy, and food (WEF) Nexus perspective may have in promoting ecosystem services in agriculture. The mediation of water quality by terrestrial systems is a key ecosystem service for a range of actors (municipalities, fishers, industries, and energy providers) and is reshaped radically by agricultural activity. To address these impacts, many programs exist to promote improved land-use practices in agriculture; however, where these practices incur a cost or other burden to the farmer, adoption can be low unless some form of incentive is provided (as in a payment for ecosystem services (PES) program). Provision of such incentives can be a challenge to sustain in the long term, if there is not a clear beneficiary or other actor willing to provide them. Successfully closing the loop between impacts and incentives often requires identifying a measurable and valuable service with a clear central beneficiary that is impacted by the summative effects of the diffuse agricultural practices across the landscape. Drawing on cases from our own research, we demonstrate how the WEF Nexus perspective—by integrating non-point-source agricultural problems under well-defined energy issues—can highlight central beneficiaries of improved agricultural practice, where none may have existed otherwise.

Selecting appropriate crops and applying deficit irrigation can help increase water productivity in water-limited regions such as the Mediterranean. The objective of this study was to develop water production functions of major cereal and legume crops under the same environmental and management conditions. Bread and durum wheat, faba bean, chickpea, and lentil were grown under full supplemental irrigation (FSI), two deficit irrigations levels of 2/3 of FSI (2/3SI) and 1/3 of FSI (1/3SI), and under rainfed conditions (no irrigation). In average, the actual evapotranspirations (ETs) under FSI were 549, 552, 365, 451 and 297mm, for bread wheat, durum wheat, faba bean, chickpea and lentil, respectively. For the same crops, they were 463, 458, 330, 393 and 277mm for the treatment 2/3SI and 357, 351, 265, 318 and 244mm for the treatment 1/3SI, respectively. In the case of the rainfed treatment, ETs for the mentioned crops were 250, 251, 227, 237 and 215mm, respectively. The experiment was conducted at the ICARDA experimental station at Tel Hadya, near Aleppo, Syria, over three growing seasons from 2007 to 2010. Results showed that, in general, the treatment with 1/3 of FSI gave the highest rate of increase in grain yield and water productivity. The mean grain yield from rainfed, 1/3SI, 2/3SI, and FSI were 1.36, 3.82, 5.18, and 5.70t/ha for bread wheat; 1.24, 3.80, 5.10, and 5.75t/ha for durum wheat; 1.57, 2.35, 2.86, and 3.54t/ha for faba bean, 1.36, 2.63, 3.36, and 3.74t/ha for chickpea, and 0.64, 1.16, 1.42, and 1.58t/ha for lentil respectively. Grain yield reductions due to the application of 2/3SI were around 10, 5, 15.6, and 10.2% of FSI on average for wheat, chickpea, faba bean, and lentils, respectively. Deficit irrigation at 2/3SI increased water productivity compared to rainfed treatments, by 200, 223, 126, 148 and 190% for bread wheat, durum wheat, faba bean, chickpea, and lentils, respectively. However, differences in total water productivity of crops grown under full irrigation compared to deficit irrigation were not significant. Irrigation water productivity ranged from 25kgha⁻¹mm⁻¹ in wheat with 1/3SI to 10kgha⁻¹mm⁻¹ for legumes under the FSI treatment. Unlike legumes, maximizing wheat grain yield caused a decline in water productivity.