Food and water resources are closely interconnected through economic supply chains. Existing studies have identified critical sectors as either direct water users or food consumers indirectly driving upstream water uses. However, sectors acting as intermediate transmission centres in the virtual water network driven by final food demand are overlooked. Production efficiency improvement of these critical transmission sectors (i.e., using less upstream inputs to produce unitary output) could indirectly reduce water uses of the whole supply chains. Taking China as the case, this study identifies critical transmission sectors for food-water nexus at the provincial level, based on an environmentally-extended multi-regional input-output model and the concept of betweenness. Results show that the agricultural products sectors in Shandong, Heilongjiang, and Hubei are the top three transmission sectors. They transmit 4.6, 4.1, and 3.0 billion m³ of embodied water resources, respectively. Some important transmission sectors, such as the cotton in Xinjiang and chemical industry in Jiangsu, cannot be identified by production-based and consumption-based methods. Results also highlight the necessity of strengthening inter-regional and inter-sectoral cooperation, because partial critical transmission sectors are not located in the demand provinces. Betweenness-based results can provide additional hotspots for developing sector-oriented policies for the synergistic management of food and water resources.

Irrigated agriculture is the backbone of Central Asian economies. Therefore, efficient irrigation water management is of crucial importance to the sustainable crop production in the region. Presented here are two studies aiming to improve agricultural water productivity â?? ET-based irrigation scheduling in Uzbekistan; and valuation of ecosystem services in Kazakhstan. The ET-based irrigation scheduling method has potential to replace subjective daily water management decisions at Water Users Association level with crop water demand-based decisions to improve water-use efficiency. Results from a two year study show that there can be a 32-35% saving of water when irrigation is applied using the ET-based scheduling method. The pilot plots are representative of 38% of irrigated area in Fergana Valley (241,407ha) and 50% in Khorezm (137,500ha) area. If this methodology is widely adopted, large amounts of water can be saved which can be diverted for other purposes. Flood irrigation of cotton is practiced on 128,000ha in the Bugunski Reservoir watershed of Kazakhstan. This practice is unsustainable due to seasonal unavailability in water supply and depletion of river discharges that were historically important at maintaining water levels downstream in nearby wetlands and the Aral Sea. Farmer surveys were used along with RIOS and SWAT modeling to evaluate alternative irrigation practices and cropping systems that can conserve water from the Bugunski Reservoir while maintaining farmer incomes. Simulations show significant reductions in irrigation water demand in the alternative scenario relative to the baseline scenario. Under baseline flood irrigation of cotton, annual irrigation demand was 928 MCM/yr averaged over the 32 year climatic record simulated. Irrigation demand decreased by 38% to 573 MCM/yr when 40,439ha of flood irrigated cotton was converted to drip irrigated cotton, sprinkler irrigated alfalfa and drip irrigated grapes. This represents a savings of 355 MCM/yr in water extracted from irrigation canals and groundwater wells | Vinay Nangia. (7/11/2016). Managing Scarce Water Resources in Irrigated Agri-Food Systems of Central Asia Two Case Studies. Phoenix, United States: American Society of Agronomy.

In this study, an inexact fractional programming method is employed for planning the regional-scale water-energy-food nexus (WEFN) system. The IFP cannot only deal with uncertainties expressed as interval parameters, but also handle conflicts among multiple decision stakeholders. The IFP approach is then applied to planning the WEFN system of Henan Province, China. An IFP-WEFN model has been established under consideration of various restrictions related to water and energy availability, as well as food demand. Solutions of the planting areas for different crops in different periods have been generated. The results suggested that there would be a significant increase for vegetable cultivation with an increasing rate of 24.4% and 30% respectively for the conservative and advantageous conditions, followed by the fruit cultivation. In comparison, the planting area of cotton would be decreased with a decreasing rate of 21.2%, and there would also be an explicit decrease for rice cultivation. These results can help generate a desired planting scheme in order to achieve a maximized unit benefit with respect to the water utilization. Comparison between the IFP-WEFN model and the ILP-WEFN model indicates that, even though a slightly lower benefit is obtained from IFP-WENF model, it can result in a higher unit benefit than the planting scheme from ILP-WEFN model. Consequently, the IFP-WEFN model can help decision-makers identify the sustainable agricultural water resources management schemes with a priority of water utilization efficiency.

The prospect of climate change has revived both fears of food insecurity and its corollary, market opportunities for agricultural production. In Australia, with its long history of state-sponsored agricultural development, there is renewed interest in the agricultural development of tropical and sub-tropical northern regions. Climate projections suggest that there will be less water available to the main irrigation systems of the eastern central and southern regions of Australia, while net rainfall could be sustained or even increase in the northern areas. Hence, there could be more intensive use of northern agricultural areas, with the relocation of some production of economically important commodities such as vegetables, rice and cotton. The problem is that the expansion of cropping in northern Australia has been constrained by agronomic and economic considerations. The present paper examines the economics, at both farm and regional level, of relocating some cotton production from the east-central irrigation areas to the north where there is an existing irrigation scheme together with some industry and individual interest in such relocation. Integrated modelling and expert knowledge are used to examine this example of prospective climate change adaptation. Farm-level simulations show that without adaptation, overall gross margins will decrease under a combination of climate change and reduction in water availability. A dynamic regional Computable General Equilibrium model is used to explore two scenarios of relocating cotton production from south east Queensland, to sugar-dominated areas in northern Queensland. Overall, an increase in real economic output and real income was realized when some cotton production was relocated to sugar cane fallow land/new land. There were, however, large negative effects on regional economies where cotton production displaced sugar cane. It is concluded that even excluding the agronomic uncertainties, which are not examined here, there is unlikely to be significant market-driven relocation of cotton production.

IntroductionIn the face of escalating apprehensions surrounding food security, the sustainability of food systems, and food quality, the ingenuity of resource management strategies becomes paramount. A key component within these strategies is the enhancement of chemical fertilizer utilization, an element that bears significant weight on agricultural yields and the preservation of our environment. The emergence of Integrated Water-Fertilizer Systems (IWFS) thus presents a significant innovation in boosting the efficiency of chemical fertilizer usage, necessitating in-depth examination.MethodsUtilizing a rigorous analytical framework that combines meta-frontier production function with a Two-Stage Residual Inclusion model, this study delves into the multi-dimensional impacts of IWFS adoption on fertilizer use efficiency among cotton growers in Xinjiang, China.ResultsEmpirical evidence demonstrates that those who have adopted IWFS achieve a fertilizer use efficiency score of 0.452, markedly outstripping the mean score of 0.382 among non-adopters. Intriguingly, efficiency increases proportionately with the size of the farm, hinting at a sophisticated interplay between the adoption of technology and operational parameters.DiscussionThe research further unveils additional benefits including augmented cotton yields and diminished labor inputs among adopters. These multifaceted outcomes bear significant policy implications, highlighting the transformative potential of IWFS in promoting sustainable food systems, bolstering food security, and enhancing food quality.