scholarly journals Virtual water trade: an assessment of water use efficiency in the international food trade

2006 ◽  
Vol 10 (3) ◽  
pp. 443-454 ◽  
Author(s):  
H. Yang ◽  
L. Wang ◽  
K. C. Abbaspour ◽  
A. J. B. Zehnder
Keyword(s):  
Water Use ◽  
Water Productivity ◽  
Virtual Water ◽  
Crop Water ◽  
Virtual Water Trade ◽  
Food Trade ◽  
Crop Water Productivity ◽  
Water Accounting ◽  
Use Efficiency ◽  
Global Water

Abstract. Amid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the local, national and global water budget has received much attention in recent years. Building upon the knowledge of virtual water accounting in the literature, this study assesses the efficiency of water use embodied in the international food trade from the perspectives of exporting and importing countries and at the global and country levels. The investigation reveals that the virtual water flows primarily from countries of high crop water productivity to countries of low crop water productivity, generating a global saving in water use. Meanwhile, the total virtual water trade is dominated by green virtual water, which constitutes a low opportunity cost of water use as opposed to blue virtual water. A sensitivity analysis, however, suggests high uncertainties in the virtual water accounting and the estimation of the scale of water saving. The study also raises awareness of the limited effect of water scarcity on the global virtual water trade and the negative implications of the global water saving for the water use efficiency and food security in importing countries and the environment in exporting countries. The analysis shows the complexity in evaluating the efficiency gains in the international virtual water trade. The findings of the study, nevertheless, call for a greater emphasis on rainfed agriculture to improve the global food security and environmental sustainability.

scholarly journals Water Footprint and Virtual Water Trade: The Birth and Growth of a New Research Field in Spain

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2641
Author(s):  
Maite M. Aldaya ◽  
Alberto Garrido ◽  
Ramón Llamas
Keyword(s):  
Water Use ◽  
Water Footprint ◽  
Water Productivity ◽  
Virtual Water ◽  
Research Field ◽  
Point Of View ◽  
Green Water ◽  
Productivity Analysis ◽  
Virtual Water Trade ◽  
Water Accounting

The growth in the number of studies applying and expanding the concepts of the water footprint and virtual water trade in Spain has generated a wealth of lessons and reflections about the scarcity, allocation, productive use, and management of water from the viewpoint of a semi-arid country. This paper reviews the evolution of this research field in Spain since its introduction in 2005 and reflects on its main contributions and issues of debate. It shows how these concepts can be useful tools for integrated water accounting and raising awareness, when used with certain precautions: (1) Supply-chain thinking, taking into account value chains and the implications of trade, generally ignored in water management, can help to address water scarcity issues and sustainable water use. (2) Green water accounting incorporates land use and soil management, which greatly influences hydrological functioning. (3) The grey water footprint indicator analyzes pollution from an ecosystem point of view and facilitates the understanding of the water quantity and quality relationship. (4) Apparent water productivity analysis, innovatively incorporated into Spanish studies, considers the economic and social aspects associated with water use. However, the decision-making context should be broader, contextualizing and complementing water information with other indicators.

scholarly journals Virtual water trade flows and savings under climate change

2013 ◽  
Vol 10 (1) ◽  
pp. 67-101 ◽  
Author(s):  
M. Konar ◽  
Z. Hussein ◽  
N. Hanasaki ◽  
D. L. Mauzerall ◽  
I. Rodriguez-Iturbe
Keyword(s):  
Climate Change ◽  
Water Use Efficiency ◽  
Water Use ◽  
Virtual Water ◽  
Hydrologic Model ◽  
Trade Flows ◽  
Virtual Water Trade ◽  
Food Trade ◽  
Use Efficiency ◽  
The Impact

Abstract. The international trade of food commodities links water and food systems, with important implications for both water and food security. The embodied water resources associated with food trade are referred to as "virtual water trade". We present the first study of the impact of climate change on global virtual water trade flows and associated savings for the year 2030. In order to project virtual water trade under climate change, it is essential to obtain projections of both bilateral crop trade and the water-use efficiency of crops in each country of production. We use the Global Trade Analysis Project (GTAP) to estimate bilateral crop trade flows under changes in agricultural productivity. We use the H08 global hydrologic model to estimate the water-use efficiency of each crop in each country of production and to transform crop flows into virtual water flows. We find that the total volume of virtual water trade is likely to go down under climate change. However, the staple food trade is projected to save more water across most climate impact scenarios, largely because the wheat trade re-organizes into a more water-efficient structure. These findings indicate that trade may be an adaptation measure to climate change with ramifications for policy.

scholarly journals Corn and Sorghum ET, E, Yield, and CWP as Affected by Irrigation Application Method: SDI versus Mid-Elevation Spray Irrigation

2019 ◽  
Vol 62 (5) ◽  
pp. 1377-1393
Author(s):  
Steven R. Evett ◽  
Gary W. Marek ◽  
Paul D. Colaizzi ◽  
David K. Brauer ◽  
Susan A. O’Shaughnessy
Keyword(s):  
Soil Water ◽  
Plant Height ◽  
Water Use ◽  
Water Productivity ◽  
High Plains ◽  
Full Irrigation ◽  
Crop Water ◽  
Neutron Probe ◽  
Crop Water Productivity ◽  
Evaporative Loss

Abstract. Greater than 80% of the irrigated area in the Southern High Plains is served by center-pivot irrigation, but the area served by subsurface drip irrigation (SDI) is increasing due to several factors including declining well yields and improved yields and crop water productivity (CWP), particularly for cotton. Not as well established is the degree to which the reduced soil water evaporation (E) in SDI systems affects the soil water balance, water available to the crop, and overall water savings. Grain corn ( L.) and sorghum ( L. Moench) were grown on four large weighing lysimeters at Bushland, Texas, in 2013 (corn), 2014 and 2015 (sorghum), and 2016 (corn). Evapotranspiration (ET) was measured using the lysimeters and using a neutron probe in the surrounding fields. Two of the lysimeters and surrounding fields were irrigated with SDI, and the other two were irrigated with mid-elevation spray application (MESA). The lysimeter-measured evaporative losses were 149 to 151 mm greater from sprinkler-irrigated corn fields than from SDI fields. When growing sorghum, the lysimeter-measured evaporative losses were 44 to 71 mm greater from sprinkler-irrigated fields than from SDI fields. The differences were affected by plant height and became smaller when plant height reached the height of the spray nozzles, indicating that the use of LEPA or LESA nozzles could decrease the evaporative losses from sprinkler-irrigated fields in this region with its high evaporative demand. Annual weather patterns also influenced the differences in evaporative loss, with increased differences in dry years. SDI reduced overall corn water use by 13% to 15%, as determined by neutron probe, while either not significantly affecting yield (2016) or increasing yield by up to 19% (2013) and increasing CWP by 37% (2013) to 13% (2016) as compared with MESA full irrigation. However, sorghum yield decreased by 15% and CWP decreased by 14% in 2014 when using SDI compared with MESA full irrigation due to an overly wet soil profile in the SDI fields and deep percolation that likely caused nutrient losses. In 2015, there were no significant sorghum yield differences between irrigation methods. Sorghum CWP was significantly greater (by 14%) in one SDI field in 2015 compared with MESA fully irrigated sorghum. Overall, sorghum CWP increased by 8% for SDI compared with MESA full irrigation in 2015. These results indicate that SDI will be successful for corn production in the Texas High Plains, but SDI is unlikely to benefit sorghum production. Keywords: Corn, Crop water productivity, Evaporative loss, Evapotranspiration, Irrigation application method, Sorghum, Water use efficiency, Weighing lysimeter.

scholarly journals Implications of water policy reforms for virtual water trade between South Africa and its trade partners: economy-wide approach

Water Policy ◽  
2014 ◽  
Vol 17 (4) ◽  
pp. 649-663 ◽  
Author(s):  
Rashid Hassan ◽  
Djiby Racine Thiam
Keyword(s):  
South Africa ◽  
Water Use Efficiency ◽  
Water Use ◽  
Water Policy ◽  
Virtual Water ◽  
Policy Reforms ◽  
Virtual Water Trade ◽  
Agricultural Exports ◽  
Recent Trends ◽  
Use Efficiency

This paper employs an economy-wide framework to evaluate impacts of water and trade policy reforms in South Africa (SA) on virtual water flows. To pursue this analysis, the study derives net virtual water trade flows between SA and its partners to assess implications of recent trade agreements within the South African Development Community compared to economic cooperation with other major trading blocks (e.g. European Union, Asia, and Brazil, Russia, India and China (BRIC)). Recent trends in actual trade confirm model predictions that liberalization of water allocation would switch water from field crops to horticulture and promote growth in non-agricultural exports. The results suggest that it is necessary to introduce policies that enhance likely outcomes of liberalization promoting higher water use efficiency within irrigation agriculture such as increased adoption of more efficient irrigation methods (sprinkler, drip, etc.) as water becomes more expensive under wider open competition. Moreover, investment in higher water use efficiency and improved competitiveness of dryland agriculture therefore represent the sound economic options for strengthening the capacity to achieve food security objectives as the country strives to lower net water exports. Finally, careful coordination of trade and water policy reforms is another necessary challenge for SA's strive to manage a water stressed economy.

scholarly journals Virtual water highway: water use efficiency in global food trade

2006 ◽  
Vol 3 (1) ◽  
pp. 1-26 ◽  
Author(s):  
H. Yang ◽  
L. Wang ◽  
K. C. Abbaspour ◽  
A. J. B. Zehnder
Keyword(s):  
Environmental Sustainability ◽  
Water Productivity ◽  
Virtual Water ◽  
High Water ◽  
Policy Instrument ◽  
Irrigated Agriculture ◽  
Virtual Water Trade ◽  
Food Trade ◽  
Global Food Security ◽  
Global Food

Abstract. Amid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the regional, national and global water budget has received much attention in recent years. Built upon the knowledge of virtual water accounting in the literature, this study examines the efficiency of the resource use embodied in the global virtual water trade from the perspectives of exporting and importing countries. Different characteristics between "green" and "blue" virtual water corresponding to rainfed and irrigated agriculture are elaborated. The investigation reveals that the virtual water flows primarily from countries of high water productivity to countries of low water productivity, generating a global saving of water resources. Meanwhile, the domination of green virtual water in the total virtual water trade constitutes low opportunity costs and environmental impacts as opposed to blue virtual water. The results suggest efficiency gains in the global food trade in terms of water resource utilization. The study raises awareness of negative impacts of increasing reliance on irrigation for food production in many countries, including food exporting countries. The findings of the study call for a greater emphasis on rainfed agriculture to improve global food security and environmental sustainability.

scholarly journals Recent evolution of China's virtual water trade: analysis of selected crops and considerations for policy

2013 ◽  
Vol 10 (9) ◽  
pp. 11613-11641 ◽  
Author(s):  
J. Shi ◽  
J. Liu ◽  
L. Pinter
Keyword(s):  
Supply Chain ◽  
South America ◽  
Water Productivity ◽  
Virtual Water ◽  
Crop Water ◽  
Trade Network ◽  
Virtual Water Trade ◽  
Grain Crops ◽  
North And South America ◽  
North And South

Abstract. China has dramatically increased its virtual water import unconsciously for recent years. Many studies have focused on the quantity of traded virtual water but very few go into analysing geographic distribution and the properties of China's virtual water trade network. This paper provides a calculation and analysis of the crop-related virtual water trade network of China based on 27 major primary crops between 1986 and 2009. The results show that China is a net importer of virtual water from water-abundant areas of North and South America, and a net virtual water exporter to water-stressed areas of Asia, Africa, and Europe. Virtual water import is far larger than virtual water export and in both import and export a small number of trade partners control the supply chain. Grain crops are the major contributors to virtual water trade, and among grain crops soybeans, mostly imported from the US, Brazil and Argentina are the most significant. As crop yield and crop water productivity in North and South America are generally higher than those in Asia and Africa, the effect of China's crop-related virtual water trade positively contributes to optimizing crop water use efficiency at the global scale. In order to mitigate water scarcity and secure the food supply, virtual water should be actively incorporated into national water management strategies. From the national perspective, China should reduce the export and increase the import of water-intensive crops. But the sources of virtual water import need to be further diversified to reduce supply chain risks and increase resilience.

scholarly journals Intercropping Optimizes Soil Temperature and Increases Crop Water Productivity and Radiation Use Efficiency of Rainfed Potato

2019 ◽  
Vol 96 (5) ◽  
pp. 457-471 ◽  
Author(s):  
Shadrack O. Nyawade ◽  
Nancy N. Karanja ◽  
Charles K. K. Gachene ◽  
Harun I. Gitari ◽  
Elmar Schulte-Geldermann ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Water Productivity ◽  
Radiation Use Efficiency ◽  
Crop Water ◽  
Crop Water Productivity ◽  
Use Efficiency ◽  
Radiation Use

Managing water resources in Libya through reducing irrigation water demand: more crop production with less water use

2013 ◽  
Vol 44 ◽  
pp. 95-102
Author(s):  
Saad Ahmad Alghariani
Keyword(s):  
Water Use ◽  
Water Demand ◽  
Crop Production ◽  
Crop Yields ◽  
Agricultural Research ◽  
Water Productivity ◽  
National Level ◽  
Crop Water ◽  
Irrigation Water Demand ◽  
Crop Water Productivity

AbstractThe looming water crisis in Libya necessitates taking immediate action to reduce the agricultural water demand that consumes more than 80% of the water supplies. The available information on water use efficiency and crop water productivity reveals that this proportion can be effectively reduced while maintaining the same, if not more, total agricultural production at the national level. Crop water productivity, which is depressingly low, can be doubled through implementing several measures including relocating all major agricultural crops among different hydroclimatic zones and growth seasons; crop selection based on comparative production advantages; realisation of the maximum genetically determined crop yields; and several other measures of demand water management. There is an urgent need to establish the necessary institutional arrangements that can effectively formulate and implement these measures as guided by agricultural research and extension services incorporating all beneficiaries and stakeholders in the process.

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