One of the needs of a sustainable decision-making system in agriculture is to determine the role of energy in the food production cycle. Wind energy turbines can be built in agricultural fields for groundwater exploitation and reduce the cost of energy supply for the pumping system. This study was conducted to evaluate the effect of wind energy and economics on sustainable planning of agricultural water resources. A multiobjective framework was developed based on the nondominated sorting principle and water cycle optimizer. Maximization of benefit per cost ratio for the total cropping pattern and minimization of energy consumption for the growing season were addressed as the objectives of the nonlinear problem. The prediction of biomass production was made by simulating a hybrid structure between the soil moisture balance in the root zone area and the development of the canopy cover of each crop. The results showed that the objectives of the problem have been met by irrigation planning using climatic constraints and drought stresses. About 35% of the total water requirement of plants with a higher harvest index (watermelon, melon, etc.) is in the maturing stage of the shade cover. HIGHLIGHTS The role of wind energy variables has been considered in the agricultural yield production.; A multiobjective framework was developed based on the nondominated sorting principle and water cycle optimizer.; The proposed optimization method showed that the total water productivity increased significantly by 38%.;

Security measures of three resources; water, energy and food are analyzed for thirty two countries in the Asia Pacific region which are faced to Pacific Ocean, in terms of amounts of the resource, self-production, and diversity of sources of each resource. Diversity for all the three resources is also analyzed using surface water and groundwater for water sources; hydro power, geothermal power, solar, and biomass for energy; and cereals, vegetable, fruit, meat, and fish for food. We see high diversity of sources of water in the US and the Philippines, and a low diversity of sources of food in the US, Canada, and Indonesia. These security measures including water security show new hydrological insight for Asia-Pacific region.

1. Growth and reproduction of Daphnia fed lake seston were measured in two categories of meso- to eutrophic lakes differing with respect to terrestrial organic matter influence (humic and clear water lakes). The content of highly unsaturated fatty acids (HUFA), P and N, as well as the taxonomical composition of seston were analysed. 2. Seston HUFA and C : P ratios were similar between lake categories, whereas C : N ratios were lower in the clear water lakes in both spring and summer. Despite the similarity in HUFA and P content of seston, Daphnia growth rate, clutch size and the proportion of gravid females were, respectively, about 1.5, 3 and 6 times higher in the clear water lakes. 3. Differences in growth and reproduction were related to a combination of higher N content and good fatty acid quality of the seston in the clear water lakes. Relatively high biomass of edible algae, such as Rhodomonas sp. and Cryptomonas sp., in the clear water lakes, and differences in water pH likely contributed to the observed differences in Daphnia growth and reproduction between lake categories. Additionally, it is possible that Daphnia was energy limited in the humic lakes despite high particulate organic carbon (POC) concentrations, as the contribution of non-algal and detrital C to the POC pool was high. 4. Our results suggest that dietary HUFA content has the potential to improve herbivore growth and reproduction if N and P are not limiting. N merits more attention in studies of zooplankton nutrition.

With the world's population set to increase by 65% (3.7 billion) by approximately 2050, the additional food required to feed future generations will put further enormous pressure on freshwater resources. This is because agriculture is the largest single user of fresh water, accounting for approximately 75% of current human water use. At present approximately 7% of the world's population live in areas where water is scarce. This is predicted to rise to a staggering 67% of the world's population by 2050. Because of this water scarcity and because new arable land is also limited, future increases in production will have to come mainly by growing more food on existing land and water. This paper looks at how this might be achieved by examining the efficiency with which water is used in agriculture. Globally, in both irrigated and rain fed agriculture only about 10-30% of the available water (as rainfall, surface or groundwater) is used by plants as transpiration. In arid and semi-arid areas, where water is scarce and population growth is high, this figure is nearer 5% in rain fed crops. There is, therefore, great potential for improving water use efficiency in agriculture, particularly, in those areas where the need is greatest. The technical basis for improving agricultural water use efficiency is illustrated. This may be achieved by increasing the total amount of the water resource that is made available to plants for transpiration and/or by increasing the efficiency with which transpired water produces biomass. It is concluded that there is much scope for improvement, particularly, in the former and that future global change research should shift its emphasis to addressing this real and immediate challenge.

This paper is a perspective paper, which investigates whether the water footprint (WF) concept addresses the water–food–energy–ecosystem nexus. First, the nexus links between (1) the planetary boundary freshwater resources (green and blue water resources) and (2) food security, energy security, blue water supply security and water for environmental flows/water for other ecosystem services (ES) are analysed and graphically presented. Second, the WF concept is concisely discussed. Third, with respect to the nexus, global water resources (green and blue) availability and use are discussed and graphically presented with an indication of quantities obtained from the literature. It is shown which of these water uses are represented in WF accounting. This evaluation shows that general water management and WF studies only account for the water uses agriculture, industry and domestic water. Important water uses are however generally not identified as separate entities or even included, i.e. green and blue water resources for aquaculture, wild foods, biofuels, hydroelectric cooling, hydropower, recreation/tourism, forestry (for energy and other biomass uses) and navigation. Fourth, therefore a list of essential separate components to be included within WF accounting is presented. The latter would be more coherent with the water–food–energy–ecosystem nexus and provide valuable extra information and statistics.

In this work, an experimental study was done in an autoclave reactor to evaluate the gasification characteristics of food waste in supercritical water. The effects of reaction temperature (550–700 °C), residence time (0–30 min), feedstock concentration (5 wt%-9 wt.%), catalyst type (K₂CO₃, Na₂CO₃, and Raney-Ni), and catalyst loading (Catalyst/dry feedstock 0.5–2) on gas production and liquid products were investigated. The results indicated that higher reaction temperature and longer residence time positively promoted food waste gasification. The organic compound species in liquid products decreased quickly to form gas products with the increased temperature, and the aromatic compounds were the key organic matter for the complete gasification of food waste. The addition of catalysts could significantly convert more liquid intermediates into gaseous products, and improve the gasification performance of food waste. The catalytic performance of catalysts can be ranked as K₂CO₃> Raney-Ni > Na₂CO₃. H₂ yield and carbon gasification efficiency increased with the increase of K₂CO₃ loading, reaching the highest values of 38.29 mol kg⁻¹ and 95.84% with the addition of 14 wt% K₂CO₃, respectively. This work indicated that food waste could be well treated and utilized as an energy resource to produce H₂ by SCWG technology.

Efficient use of water and nutrients in crop production are critical for sustainable water and crop production systems. Understanding the role of humans in ensuring water and nutrient use efficiency is therefore an important ingredient of sustainable development. Crop production functions are often defined either as functions of water and nutrient deficiency or are based on economic production theory that conceptualizes production as a result of economic activities that take in inputs such as water, capital and labor and produce crop biomass as output. This paper fills a gap by consistently treating water and nutrient use and human agency in crop production, thus providing a better understanding of the role humans play in crop production. Uptake of water and nutrients are two dominant biophysical processes of crop growth while human agency, including irrigation machine power, land-preparing machine power and human labor force, determine limits of water and nutrient resources that are accessible to crops. Two crops, i.e., winter wheat and rice, which account for the majority of food crop production are considered in a rapidly developing region of the world, Jiangsu Province, China, that is witnessing the phenomenon of rural to urban migration. Its production is modeled in two steps. First water and nutrient efficiencies, defined as the ratios of observed uptake to quantities applied, are modeled as functions of labor and machine power (representing human agency). In the second step, crop yields are modeled as functions of water and nutrient efficiencies multiplied by amounts of water and fertilizers applied. As a result, crop production is predicted by first simulating water and nutrient uptake efficiencies and then determining yield as a function of water and nutrients that are actually taken up by crops. Results show that modeled relationship between water use efficiency and human agency explains 68% of observed variance for wheat and 49% for rice. The modeled relationship between nutrient use efficiency and human agency explains 49% of the variance for wheat and 56% for rice. The modeled relationships between yields and actual uptakes in the second step explain even higher percentages of observed the variance: 73% for wheat and 84% for rice. Leave-one-out cross validation of yield predictions shows that relative errors are on average within 5% of the observed yields, reinforcing the robustness of the estimated relationship and of conceptualizing crop production as a composite function of bio-physical mechanism and human agency. Interpretations based on the model reveal that after 2005, mechanization gradually led to less labor being used relative to machinery to achieve same levels of water use efficiency. Labor and irrigation equipment, on the other hand, were found to be complimentary inputs to water use efficiency. While the results suggest interventions targeting machinery are most instrumental in increasing wheat productivity, they may exasperate rural – urban migration. Policy strategies for alleviating rural-urban migration while ensuring regional food security can nonetheless be devised where appropriate data are available.

Seagrass meadows ecosystem engineering effects are correlated to their density (which is in turn linked to seasonal cycles) and often cannot be perceived below a given threshold level of engineer density. The density and biomass of seagrass meadows (Z. marina) together with associated macrophytes undergo substantial seasonal changes, with clear declines in winter. The present study aims to test whether the seasonal changes in the density of recovering seagrass meadows affect the benthic food webs of the southern Baltic Sea (Puck Bay). It includes meiofauna, macrofauna and fish of vegetated and unvegetated habitats in summer and winter seasons. Two levels of organization have been tested – species-specific diet preferences using stable isotopes (δ13C, δ15N) in Bayesian mixing models (MixSIAR) and the community-scale food web characteristics by means of isotopic niches (SIBER). Between-habitat differences were observed for grazers, as a greater food source diversity in species from vegetated habitats was noted in both seasons. Larger between-habitat differences in winter were documented for suspension/detritus feeders. The community-wide approach showed that the differences between the habitats were greater in winter than in summer (as indicated by the lower overlap of the respective isotope niches). Overall, the presence of seagrass meadows increased ecological stability (in terms of the range of food sources utilized by consumers) in the faunal assemblage, while invertebrates from unvegetated areas shifted their diet to cope with winter conditions. Therefore, as a more complex system, not sensitive to seasonal changes, Z. marina meadows create a stable habitat with high resilience potential.

Materials, energy, and organisms from groundwater serve as resource subsidies to lotic systems. These subsidies influence food production and post-emergent fish growth and condition through nutrient inputs and water temperature changes. To test whether post-emergent fish grew faster in gaining sites, we grew hatchery post-emergent salmon in enclosures, sampled periphyton, benthic invertebrates, and wild salmon, and modeled fish growth across a gradient of groundwater – surface water exchange. Fish grew almost twice as fast in gaining (2.7%·day⁻¹) than in losing (1.5%·day⁻¹) sites. Fish from transient sites grew as much as gaining sites, but their condition was significantly lower (18.3% vs. 20.7%). Results suggest that groundwater – surface water exchange affects fish growth and energetic condition through direct and indirect pathways. Elevated nitrogen concentrations and consistently warmer water temperature in gaining sites have a strong effect on basal production with subsequent effects on invertebrate biomass, fish growth, and condition. Findings highlight the importance of groundwater – surface water exchange as a subsidy to rearing salmon and may inform strategies for restoring fish rearing habitat.

Separation of water-soluble lignins from lignocellulosic biomass provides a new and still poorly exploited feedstock to increase the sustainability of biorefineries. We applied derivatization followed by a reductive cleavage (DFRC) method, 2D-HSQC-NMR, and ³¹PNMR after ³¹P-labeling, to investigate molecular composition in water-soluble lignins obtained by alkaline oxidation from three biomass materials for energy (miscanthus, giant reed and an industrially pre-treated giant reed). Chromatographic identification of lignin products cleaved by DFRC showed a large predominance of guaiacyl (G) units in all biomasses and a lesser abundance of syringyl (S) and p-coumaryl (P) monomers. Our S/G ratios disagree with those reported in literature by other lignin separation methods. Carboxyl functions (ferulic and pcoumaric acids) were revealed by heterocorrelated ¹H–¹³C HSQC-NMR, and confirmed by ³¹P-NMR spectra of ³¹ P-labeled lignin molecules. An understanding of molecular composition of water-soluble lignins from biomass sources for energy is essential for lignin most efficient exploitation in either industrial or agricultural applications.