Adequate access to healthy, affordable food remains a great challenge in many urban areas. Among a range of interventions, urban agriculture has been identified as an important strategy to help address urban healthy food access. While urban food production is growing in popularity, the use of potable water in traditional urban agricultural installations will exacerbate gaps in water demand and availability in water-stressed cities. This paper examines the sustainable capability of urban agriculture through an integration of alternative water resources, urban vacant land and local nutritional needs. A spatial optimization model is developed to best allocate limited resources for maximal food production to address urban food deserts. The new model is applied to test the capability of relocalized food production in Tucson, Arizona, a semi-arid region with the longest continuously farmed landscape in North America. Results highlight that urban areas with restricted water access can substantially enhance their local food production capacity in an ecologically responsible manner.

Iran’s focus on food self-sufficiency has led to an emphasis on increasing water volumes available for irrigation with little attention to water use efficiency, and no attention at all to the role of consumption and trade. To better understand the development of water consumption in relation to food production, consumption, and trade, we carried out the first comprehensive water footprint assessment (WFA) for Iran, for the period 1980–2010, and estimated the water saving per province associated with interprovincial and international crop trade. Based on the AquaCrop model, we estimated the green and blue water footprint (WF) related to both the production and consumption of 26 crops, per year and on a daily basis, for 30 provinces of Iran. We find that, in the period 1980–2010, crop production increased by 175%, the total WF of crop production by 122%, and the blue WF by 20%. The national population grew by 92%, and the crop consumption per capita by 20%, resulting in a 130% increase in total food consumption and a 110% increase in the total WF of national crop consumption. In 2010, 26% of the total water consumption in the semi-arid region served the production of crops for export to other regions within Iran (mainly cereals) or abroad (mainly fruits and nuts). Iran’s interprovincial virtual water trade grew by a factor of 1.6, which was mainly due to increased interprovincial trade in cereals, nuts, and fruits. Current Iranian food and water policy could be enriched by reducing the WFs of crop production to certain benchmark levels per crop and climatic region and aligning cropping patterns to spatial differences in water availability and productivities, and by paying due attention to the increasing food consumption per capita in Iran.

The salinity tolerance of Javan rusa deer (Cervus timorensis russa) was investigated with seven stags, aged 4.5 years. Animals were offered a medium-quality chaffed lucerne hay and given five different levels of water salinity: (a) control (570 mg/kg of total dissolved salts (TDS)) and (b) 'saline' water with TDS contents of 1000, 3500, 6000 and 8500 mg/kg. Food intake, food digestibility and nitrogen balance were not affected by increasing salt concentration in drinking water, however the drinking water (DW) intake, the total (food plus drinking) water intake and the DW:dry-matter ratio increased with increasing salt concentration. Some deer given water containing 8500 mg TDS per kg showed signs of stress which included large between-day fluctuations in water intake, opening of the orbital gland, head shaking, and rapid breathing. Rusa deer can tolerate drinking water containing 6000 mg TDS per kg for at least 9 days without harmful effect but may be unable to tolerate water with 8500 mg TDS per kg.

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.

A burgeoning population, pressing development needs and increasing household consumption are rapidly accelerating water use in direct and indirect ways. Increasingly, regions around the world face growing pressure on sustainable use of their water resources especially in arid and semi-arid regions, such as Northern China. The aim of this research is to obtain an overview of the cumulative water requirement for direct (domestic) water use and indirect water use for the basic food consumption of the households in the Inner Mongolia Autonomous Region (IMAR), in order to reduce the pressure on grassland of Western China by encouraging sustainable water consumption. For indirect water use, we use VWC (virtual water content) analysis theory to analyze the total consumption package of 15 basic food types that were identified and quantified based on the household survey in 2011. In this survey, domestic water consumption data and food consumption data were collected from 209 representative households with spatial variation across three sub-regions (including meadow steppe in Hulun Buir, typical steppe in Xilin Gol, and semi-desert steppe in Ordos) and temporal variation from 1995 to 2010. The results show that the total amounts of food consumption per capita in three sub-regions all show an increasing trend, especially in Hulun Buir and Ordos. Compared to the direct water consumption, the indirect water consumption behind food production made up a major portion of total water consumption, which is affected (1) geographic locations (grassland types); (2) economic development levels and (3) grassland use policy measures. From 1995 to 2010, indirect water consumption displays a decreasing trend in Xilin Gol and Ordos due to the decrease of meat consumption and increase of fruit and vegetable consumption. When considering the amount of land per household, the grassland in Ordos still faces the great threat of high water consumption pressure. Such water consumption may affect water conservation services and productivity of grassland. Therefore, changing diet behavior and reducing the population can be considered options for sustainable use of water.

Vaca Muerta is the major region in South America where horizontal drilling and hydraulic fracturing techniques are used to extract unconventional shale oil and gas. Despite the growing interest in the Vaca Muerta resources, there is only a limited understanding of the impacts that their extraction could have on local water resources. This study uses a water balance model to investigate the hydrological implication of unconventional oil and gas extraction in this region. We find that, with current rates of extraction, water scarcity is observed for four months a year. We also find that water consumption per fractured well increased 2.5 times in the period 2012–2016 and produced water from unconventional shale formation sharply increased from roughly zero to 1.15 × 10⁶ m³ y⁻¹ in the 2009–2017 period. Our projections estimate that in this region future water consumption for unconventional oil and gas extraction will increase 2.2 times in the 2017–2024 period reaching 7.40 × 10⁶ m³ y⁻¹. The consequent exacerbation of current water scarcity will likely lead to competition with irrigated agriculture, the greatest water consumer in this semiarid region. Produced water recycling, domestic wastewater reuse, brackish groundwater use, and waterless unconventional oil and gas extraction technologies are some of the strategies that could be adopted to meet future additional water demand. Our results estimate the likely range of water consumption and production from hydraulic fracturing operations in the Vaca Muerta region under current and future conditions. These results could be used to make informed decisions for the sustainable water management in this semiarid region of Argentina.