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Water-energy-food nexus: A case study on medicinal and aromatic plants 全文
2019
Litskas, Vassilis | Chrysargyris, Antonios | Stavrinides, Menelaos | Tzortzakis, Nikolaos
Medicinal and Aromatic Plants (MAPs) are broadly cultivated in the Mediterranean but their environmental footprint is not very well studied. In this paper, Life Cycle Assessment (LCA) was applied to determine the energy balance, carbon and water footprints (CF and WF, respectively) in 50 farms, organic and conventional, where four MAP species were cultivated; spearmint (Mentha spicata), oregano (Oreganum vulgare), rosemary (Rosmarinus officinalis) and Damask rose (Rosa damascena). The lowest value for energy intensity (EI) was observed for organic spearmint (0.18 MJ/kg fresh weight; f.w.) while the highest for conventional Damask rose (5.80 MJ/kg f.w.). Statistically significant differences were observed in EI between organic and conventional farms for spearmint and Damask rose while no differences were found for oregano and rosemary. The lowest CF was observed for organic rosemary (0.051 kg CO₂-eq/kg f.w.) while the highest for conventional Damask rose (0.463 kg CO₂-eq/kg f.w.). Statistical differences in the CF between organic and conventional farms for the four species followed the same pattern as for EI. Conventional spearmint had the lowest WF (61.5 L of water/kg f.w.) and organic Damask rose the highest (1522 L of water/kg f.w.). Statistical differences between the two management systems were observed only for Damask rose. The 50 farms were grouped according to the values of three indicators (EI, CF and WF) using cluster analysis. Four clusters were identified with 68% of the farms (34) belonging to the low footprint cluster which contained organic and conventional spearmint, oregano and rosemary farms. The other three clusters contained the (16) Damask rose farms, where the inputs were higher in comparison to the other three species and the highest footprint clusters contained conventional rose farms. Our work suggests that MAPs are viable candidates for the implementation of sustainable agriculture in the Mediterranean.
显示更多 [+] 显示较少 [-]Seasonal Energy, Water, and Food Consumption of Negev Chukars and Sand Partridges 全文
1987
Kam, Michael | Degen, A Allan | Nagy, Kenneth A.
Chukars (Alectoris chukar) and Sand Partridges (Ammoperdix heyi), two ground—dwelling phasianids, are permanent residents of the Negev desert and are sympatric over much of their ranges. Sand Partridges (body mass = 150—250 g), however, inhabit only arid and very arid areas, whereas Chukars (mb = 350—600 g) are widely distributed and inhabit deserts only at the margins of their ranges. We compared some of the desert adaptations of these phasianids by measuring the seasonal field metabolic rates (FMR) and water influxes (using doubly labelled water), diet selection, and food requirements of free—living Chukars and Sand Partridges at a site where both species occurred. Both species showed adaptation in the form of low energy metabolism, which ranged from 43 to 81% of that expected for birds of similar body mass. During summer, Sand Partridges had lower energy expenditures (5.47 kJ°g— ⁰ . ⁶ ¹°d— ¹) and water influxes 72.3 mL°kg— ⁰.⁷ ⁵°d— ¹) than did Chukars (6.42 kJ°g— ⁰ . ⁶ ¹°d— ¹ and 93.5 mL°kg— ⁰ . ⁷ ⁵°d— ¹, respectively), indicating more pronounced adjustments to arid conditions in the desert specialist. However, both species obtained more than half of their water influx in summer by drinking. Their summer diet was relatively dry, consisting mainly of seeds (80%) along with some green vegetation (18%) and, in Chukars, occasional arthropods. This situation changed abruptly after winter rains, which induced germination and reduced the availability of seeds. Chukars were unable to maintain energy balance in the face of low ambient temperatures and a diet (90% green vegetation) that contained much water but comparatively little energy, and they mobilized fat reserves to meet energy requirements. Most Sand Partridges left the study area after winter rains, apparently migrating to the lower elevation, warmer, and drier Arava (part of the Rift Valley). The winter rainy season appears to be the most stressful time of the year for both species. The adaptations to hot, dry conditions possessed by Sand Partridges may be accompanied by constraints on their abilities to cope with cool, wet conditions, and this may restrict them to arid and very arid habitats.
显示更多 [+] 显示较少 [-]Implications of non-sustainable agricultural water policies for the water-food nexus in large-scale irrigation systems: A remote sensing approach 全文
2017
Al Zayed, Islam Sabry | Elagib, Nadir Ahmed
This study proposes a novel monitoring tool based on Satellite Remote Sensing (SRS) data to examine the status of water distribution and Water Use Efficiency (WUE) under changing water policies in large-scale and complex irrigation schemes. The aim is to improve our understanding of the water-food nexus in such schemes. With a special reference to the Gezira Irrigation Scheme (GeIS) in Sudan during the period 2000–2014, the tool devised herein is well suited for cases where validation data are absent. First, it introduces an index, referred to as the Crop Water Consumption Index (CWCI), to assess the efficiency of water policies. The index is defined as the ratio of actual evapotranspiration (ETa) over agricultural areas to total ETa for the whole scheme where ETa is estimated using the Simplified Surface Energy Balance model (SSEB). Second, the tool uses integrated Normalized Difference Vegetation Index (iNDVI), as a proxy for crop productivity, and ETa to assess the WUE. Third, the tool uses SSEB ETa and NDVI in an attempt to detect wastage of water. Four key results emerged from this research as follows: 1) the WUE has not improved despite the changing agricultural and water policies, 2) the seasonal ETa can be used to detect the drier areas of GeIS, i.e. areas with poor irrigation water supply, 3) the decreasing trends of CWCI, slope of iNDVI-ETa linear regression and iNDVI are indicative of inefficient utilization of irrigation water in the scheme, and 4) it is possible to use SSEB ETa and NDVI to identify channels with spillover problems and detect wastage of rainwater that is not used as a source for irrigation. In conclusion, the innovative tool developed herein has provided important information on the efficiency of a large-scale irrigation scheme to help rationalize laborious water management processes and increase productivity.
显示更多 [+] 显示较少 [-]Supercritical water gasification of biomass and agro-food residues: Energy assessment from modelling approach 全文
2020
Macrì, Domenico | Catizzone, Enrico | Molino, Antonio | Migliori, Massimo
The gasification of biomass in supercritical water is a promising technology for hydrogen production and the paper reports a thermodynamic analysis, based on minimization of Gibbs free energy, of the gasification with supercritical water of different biomass and agro-food residues: almond shells, digestate from wastewater treatment, algae and manure sludge. Numerical simulations were performed in order to assess the effect of temperature, pressure and biomass-to-water ratio on gas-phase yield and composition.A partial energy integration was also discussed, by considering the energy recovery from a turbine expansion of the gas-phase stream leaving the gasifier. The proposed thermodynamic approach allows predicting not only gasification efficiency of gasifier but also energy balance on the entire gasification process. Results showed that the dry substrates (almond shells and algae more than digestate and sludge) tend to form more carbon monoxide. Besides, data comparison revealed that the produced hydrogen comes from biomass and water for high process temperature, while when temperature decreases, the thermodynamic path tends to promote water formation from the hydrogen of the dry biomass.
显示更多 [+] 显示较少 [-]Adopting plastic film mulching system in the food-energy-water-carbon nexus to the sustainable dryland agriculture 全文
2024
Li Zhang | Huihui Wei | Meilan Zhang | Yang Yang | Yalan Huang | Ning Chai | Xulong Zhang | Kaiping Zhang | Feng-Min Li | Shiqian Guo | Feng Zhang
Agricultural production development and ecological environmental protection are the main challenges facing dryland agriculture in the Loess Plateau. Over the past four decades, this region has transitioned from a state of food shortage and ecological deterioration to a new phase with plentiful food supply and improved ecological environment. However, it remains unclear how this system navigates resource and environmental constraints, balancing economic growth and ecological preservation. Here we conducted integrated and systematic analysis by combining process-based biogeochemical model, statistical yearbook data, and rural social surveys with the life cycle assessment (LCA) methodology. The yield, economic benefits, carbon footprint (CF), and energy balance of maize, winter wheat, and potato within the plastic film mulching (PFM) cropping system surpassed those of conventional tillage, while the water footprint (WF) was lower. Among them, soil N2O was the primary source of direct greenhouse gas (GHG), while mineral fertilizer (40–71 % and 52−73 %) and agricultural diesel (13−18 % and 17−18 %) were the main contributors to indirect GHG and energy inputs. Moreover, the food-energy-water-carbon (FEWC) nexus of maize being harmonized during 1980–2019 (0.50–1.00), and those of winter wheat and potato being harmonized after 2000 (0.51–0.98 and 0.54–0.97, respectively). The maize also was more profitable than winter wheat and potato. The changing rates of yield, agricultural net profit (ANP), WF, and CF of major crops in the Loess Plateau exhibited consistent increase over time, albeit with regional differentiation characteristics. These results highlight that PFM system achieved high economic benefits and low environmental costs, and it contributed to establishing resource-efficient, production-effective, and eco-friendly dryland agriculture in China and the world.
显示更多 [+] 显示较少 [-]Validation of energy intake measurements determined from observer-recorded food records and recall methods compared with the doubly labeled water method in overweight and obese individuals
2002
Hise, M.E. | Sullivan, D.K. | Jacobsen, D.J. | Johnson, S.L. | Donnelly, J.E.
Background: Measurements of dietary intake in obese and overweight populations are often inaccurate because food intakes are underestimated. Objective: The purpose of this study was to evaluate the validity of the combined use of observer-recorded weighed-food records and 24-h snack recalls in estimating energy intakes in overweight and obese individuals. Design: Subjects were 32 healthy women and 22 healthy men with mean body mass indexes (in kg/m2) of 29.5 and 30.3, respectively. Energy intake (EI) was measured over 2 wk in a university cafeteria. No restrictions were made on meal frequency or EI. To document food consumed outside the cafeteria, 24-h snack recalls were conducted before meals. Energy expenditure (EE) was measured with the doubly labeled water (DLW) method (EEDLW). Energy balance was determined by measuring body weight at the beginning and end of the 2-wk period. Results: The mean EI in the women (10.40 +/- 1.94 MJ/d) and men (14.37 +/- 3.21 MJ/d) was not significantly lower than the EEDLW in the women (10.86 +/- 1.76 MJ/d) and men (14.14 +/- 2.83 MJ/d). The mean EI represented 96.9 +/- 17.0% and 103 +/- 18.9% of the measured EE for women and men, respectively. There were no significant changes in weight in the group as a whole or by sex at the end of the testing period; the men lost 0.23 +/- 1.58 kg and the women lost 0.25 +/- 1.09 kg. Conclusion: The combination of observer-recorded food records and 24-h snack recalls is a valid method for measuring EI in overweight and obese individuals.
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