Analysis the water–food–energy nexus is the first step to assess the decision maker in developing and evaluating national strategies that take into account the nexus. The main objective of the current research is providing a method for the decision makers to analysis the water–food–energy nexus of the crop production system at the national level and carrying out a quantitative assessment of it. Through the proposed method, indicators considering the water and energy consumption, mass productivity, and economic productivity were suggested. Based on these indicators a water–food–energy nexus index (WFENI) was performed. The study showed that the calculated WFENI of the Egyptian summer crops have scores that range from 0.21 to 0.79. Comparing to onion (the highest scoring WFENI,i.e., the best score), rice has the lowest WFENI among the summer food crops. Analysis of the water–food–energy nexus of forty-two Egyptian crops in year 2010 was caried out (energy consumed for irrigation represent 7.4% of the total energy footprint). WFENI can be applied to developed strategies for the optimal cropping pattern that minimizing the water and energy consumption and maximizing their productivity. It can be applied as a holistic tool to evaluate the progress in the water and agricultural national strategies. Moreover, WFENI could be applied yearly to evaluate the performance of the water-food-energy nexus managmant.

Air tanah sangat potensial untuk mengairi tanaman pangan terutama palawija di lahan tadah hujan. Salah satu cara pemanfaatan air tanah tersebut dengan membuat sumur pantek. Hal ini memungkinkan karena kedalaman air tanah relatif dangkal (10-15 m dari permukaan tanah). Pengembangan air tanah tersebut akan berdaya guna apabila manfaat yang diperoleh cukup besar dibandingkan dengan biaya yang dikeluarkan. Frekuensi pemberian air tiap 14 hari tidak berpengaruh nyata terhadap hasil kedelai dan jagung di Sukamandi (Subang), Haurgeulis (Indramayu) dan Adipala (Cilacap) dibandingkan pemberian air tiap 7 maupun 10 hari. Penyaluran air yang berasal dari pompa menggunakan slang plastik untuk mengurangi kehilangan air selama penyaluran sehingga menghemat bahan bakar pompa. Besar biaya untuk pengoperasian pompa rata-rata Rp 240.000,- dan Rp 265.000,- masing-masing untuk kedelai dan jagung sedangkan keuntungan bersih rata-rata budidaya kedelai dan jagung masing-masing Rp 374.000,-/ha dan Rp 321.000,-/ha

Summaries (En)

Population growth, rapid urbanization, changing diets, and economic development are among the major driving factors of increased demand for water, food and land. In this study, an integrated model was developed for managing land-water-food nexus. A water footprint-based fuzzy fractional programming (WFFP) is developed for optimizing resource allocations toward sustainable food and water security under the agricultural, food, socioeconomic, and natural resource constraints. By calculating the blue and green water footprint of each crop, optimum food requirements were converted into optimal cropping options. The WFFP method can tackle ratio optimization problems associated with fuzzy information, in which fuzzy possibilistic programming is integrated into a linear fractional programming framework. The method is applied to a case study of the Three (Yangtze-Yellow-Lantsang) Rivers Headwaters Region of China. The results can provide the basis for water and agricultural policies formulation and land-water-food nexus management in the study region.

This paper analyzes virtual water trade flows through food products between India and its trading partners. It relies on the gravity model of trade and estimates a panel data fixed effect regression to identify drivers of virtual water trade. Our results show that India was the net exporter of virtual water in food products during 1990–2013; however later it turned out to be its net importer. Further our analysis shows distance between trading partners as the primary driver of virtual water trade. India prefers trading with its neighbours to reduce transportation costs. The availability of arable land and water used in crop production are limiting factors for production of food crops and thus act as essential factors in deciding the virtual water trade flows. These findings indicate that resource endowment factors influence bilateral virtual water trade flows.

Natural resources are consumed in food production, and food loss is consequently accompanied with a loss of resources as well as greenhouse gas (GHG) emissions. This study analyses food loss based on India-specific production data (for the year 2013) and reported food loss rates during production and post-harvest stages of major food crops and animal products in India. Further, the study evaluates the environmental impacts of food loss in terms of utilization of water, land resources and GHG emissions. The total food loss in harvest and post-harvest stages of the food supply chain for the selected food items amounted to 58.3 ± 2.22 million tonnes (Mt) in the year 2013 with the highest losses by mass in sugarcane and rice. The volume of water associated with the food losses was found to be 115 ± 4.15 billion m³, of which 105 ± 3.77 billion m³ was direct water use (blue + green) and 9.54 ± 0.38 billion m³ was indirect water use (grey). Wasted sugarcane and rice were found to be the largest contributors for water loss. Land footprint and carbon footprint associated with food loss were found to be 9.58 ± 0.4 million hectares (Mha) and 64.1 ± 3.8 Mt CO₂eq, respectively, with rice accounting for the largest impact in both. This highlights the immediate need for quantification and taking measures for minimization of losses across the food supply chains in India.

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.

Oil and gas extraction in the western United States generates significant volumes of produced water (PW) that is typically injected into deep disposal wells. Recently, crop irrigation has emerged as an attractive PW reuse option, but the impact on plant immune response is not known. In this study, we conducted a 3-month greenhouse pot study. Spring wheat (Triticum aestivum) was irrigated 3 times a week with 150 mL (∼80–100% of soil water holding capacity) with one of four irrigation treatments: tap water control, 10% PW dilution, 50% PW dilution, and salt water (NaCl50) control containing the same amount of total dissolved solids as PW50 to determine the effect on disease resistance. The wheat leaves were inoculated with either bacterial or fungal pathogens and changes in pathogenesis-related PR-1 and PR-5 gene expression were measured from the leaf tissue. PW50 experienced the largest relative suppression of PR-1 and PR-5 gene expression compared to noninfected wheat, followed by PW10, NaCl50, and the tap water control. A combination of PW contaminants (boron, total petroleum hydrocarbons, and NaCl) are likely reducing PR-gene expression by reallocating metabolic resources to fight abiotic stresses, which then makes it more challenging for the plants to produce PR genes to fight pathogens. This study provides the first evidence that plant disease resistance is reduced due to irrigation with reused PW, which could have negative implications for food security.