Determination of virtual water content of rice and spatial characteristics analysis in China

Abstract. China is a water-stressed country, and agriculture consumes the bulk of its water resources. Assessing the virtual water content (VWC) of crops is one important way to develop efficient water management measures to alleviate water resource conflicts among different sectors. In this research, the VWC of rice, a major crop in China, is taken as the research object. China covers a vast land area, and the VWC of rice varies widely between different regions. The VWC of rice in China is assessed and the spatial characteristics are also analysed. The total VWC is the total volume of freshwater both consumed and affected by pollution during the crop production process, including both direct and indirect water use. Prior calculation frameworks of the VWC of crops did not contain all of the virtual water content of crops. In addition to the calculation of green, blue and grey water – the direct water in VWC – the indirect water use of rice was also calculated, using an input–output model. The percentages of direct green, blue, grey and indirect water in the total VWC of rice in China were found to be 43.8, 28.2, 27.6, and 0.4%. The total VWC of rice generally showed a roughly three-tiered distribution, and decreased from southeast to northwest. The higher values of direct green water usage were mainly concentrated in Southeast and Southwest China, while the values were relatively low in Northwest China and Inner Mongolia. The higher direct blue water values were mainly concentrated in the eastern and southern coastal regions and Northwest China, and low values were mainly concentrated in Southwest China. Grey water values were relatively high in Shanxi and Guangxi provinces and low in Northeast and Northwest China. The regions with high values for indirect water were randomly distributed but the regions with low values were mainly concentrated in Northwest and Southwest China. For the regions with relatively high total VWC the high values of blue water made the largest contribution, although for the country as a whole the direct green water is the most important contributor.

Download Full-text

Determination of virtual water content of rice and spatial characteristics analysis in China

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-11-1047-2014 ◽

2014 ◽

Vol 11 (1) ◽

pp. 1047-1072 ◽

Cited By ~ 1

Author(s):

L. J. Zhang ◽

X. A. Yin ◽

Y. Zhi ◽

Z. F. Yang

Keyword(s):

Water Resources ◽

Water Content ◽

Southwest China ◽

Virtual Water ◽

Northwest China ◽

Green Water ◽

Blue Water ◽

Grey Water ◽

Spatial Characteristics ◽

Water Values

Abstract. China is a water-stressed country, and agriculture consumes the bulk of its water resources. Assessing the virtual water content (VWC) of crops is one important way to develop efficient water management measures to alleviate water resources conflicts among different sectors. In this research, the VWC of rice, as a major crop in China, was assessed and the spatial characteristics were analyzed. In addition to the calculation of green, blue and grey water – the direct water in VWC – the indirect water use of rice was also calculated, using the Input–Output model. The percentages of direct green, blue, grey and indirect water in the total VWC of rice in China were 43.8, 28.2, 27.6, and 0.4%. The total VWC of rice generally showed a three-tiered distribution, and decreased from southeast to northwest. The higher values of direct green water of rice were mainly concentrated in Southeast and Southwest China, while these values were relatively low in Northwest China and Inner Mongolia. The higher direct blue water values were mainly concentrated in the eastern and southern coastal regions and Northwest China, and low values were mainly concentrated in Southwest China. Grey water values were relatively high in Shanxi and Guangxi provinces and low in Northeast and Northwest China. The regions with high values for indirect water were randomly distributed but the regions with low values were mainly concentrated in Northwest and Southwest China. For the regions with relatively high total VWC the high values of blue water made the largest contribution, although for the country as a whole the direct green water is the most important contributor.

Download Full-text

Water saving through international trade of agricultural products

Hydrology and Earth System Sciences ◽

10.5194/hess-10-455-2006 ◽

2006 ◽

Vol 10 (3) ◽

pp. 455-468 ◽

Cited By ~ 250

Author(s):

A. K. Chapagain ◽

A. Y. Hoekstra ◽

H. H. G. Savenije

Keyword(s):

Water Resources ◽

Water Use ◽

Virtual Water ◽

Water Saving ◽

Agricultural Products ◽

Green Water ◽

Blue Water ◽

Water Flows ◽

Global Water ◽

National Water

Abstract. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm3/yr. These products are however being produced with only 1253 Gm3/yr in the exporting countries, saving global water resources by 352 Gm3/yr. This saving is 28 per cent of the international virtual water flows related to the trade of agricultural products and 6 per cent of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm3/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm3/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.

Download Full-text

Analysis of virtual water flows associated with the trade of maize in the SADC region: importance of scale

Hydrology and Earth System Sciences ◽

10.5194/hess-13-1967-2009 ◽

2009 ◽

Vol 13 (10) ◽

pp. 1967-1977 ◽

Cited By ~ 15

Author(s):

J. M. Dabrowski ◽

E. Masekoameng ◽

P. J. Ashton

Keyword(s):

South Africa ◽

Water Use Efficiency ◽

Water Content ◽

Water Use ◽

Water Scarcity ◽

Virtual Water ◽

Blue Water ◽

Maize Production ◽

Water Flows ◽

Use Efficiency

Abstract. The concept of virtual water encourages a country to view agricultural crops in terms of the amount of water required to produce those crops, with a view to implementing trading policies that promote the saving of scarce water resources. Recently, increased attention has focussed on partitioning the virtual water content of crops into green and blue water (derived from rainfall and irrigation, respectively) as the latter has higher opportunity costs associated with its use and therefore impacts directly on scarcity. Maize is the most important crop traded within the SADC region. South Africa is the largest producer and exporter of maize, with the majority of its exports destined for other SADC countries. In comparison to other SADC countries, South Africa produces maize relatively efficiently, with a low virtual water content and a high green (868 m3 t−1) to blue (117 m3 t−1) water ratio. The blue water content is however higher than for maize produced in all other SADC countries, with the exception of Namibia (211 m3 t−1). Current trade patterns therefore result in a net expenditure of blue water (66×106 m3), almost all of which is exported by South Africa (65×106 m3). South Africa is one of the most water scarce countries in the region and analysis of virtual water flows indicates that current SADC maize trading patterns are influenced by national productivity as opposed to water scarcity. The virtual water content of maize was estimated for each of South Africa's nineteen Water Management Area's (WMA) and used as a proxy to represent water use efficiency for maize production. The virtual water content varied widely across all of the WMAs, ranging from 360 m3 t−1 in the Ustutu Mhlatuze to 1000 m3 t−1 in the Limpopo. A comparison of the virtual water content and production of maize (expressed as a percentage of the total national production) identified those WMAs where maize production is highly water inefficient (e.g. Lower Orange and Limpopo WMAs). Results suggest that, while a national estimate of the virtual water content of a crop may indicate a relatively efficient use of water, an analysis of the virtual water content at smaller scales can reveal inefficient use of water for the same crop. Therefore, analysis of the virtual water content of crops and trading of agricultural products at different spatial scales (i.e. regional, national and WMA) could be an important consideration within the context of water allocation, water use efficiency and alleviation of water scarcity.

Download Full-text

Water Footprint Assessment pada komoditas padi, jagung, dan kedelai di wilayah Daerah Istimewa Yogyakarta untuk mendukung sistem pertanian berkelanjutan

Jurnal Irigasi ◽

10.31028/ji.v15.i2.121-129 ◽

2020 ◽

Vol 15 (2) ◽

pp. 121

Author(s):

Fathi Alfinur Rizqi ◽

Sri Nuryani Utami

Keyword(s):

Water Footprint ◽

Virtual Water ◽

Green Water ◽

Blue Water ◽

Grey Water ◽

Development Goals

Populasi penduduk Indonesia diperkirakan akan mencapai 350 juta pada tahun 2045, mendorong Indonesia untuk meningkatkan ketersediaan pangan 3% setiap tahunnya. Program Upaya Khusus (Upsus) Padi Jagung Kedelai (Pajale), menjadi salah satu program unggulan pemerintah dalam menjawab tantangan ini. Di sisi lain, tekanan lingkungan memberikan batas jelas untuk melaksanakan proses budidaya pertanian berkelanjutan. Sebagaimana dua tujuan dari Sustainability Development Goals (SDGs) adalah menghentikan kelaparan dan kepastian akses terhadap air. Konsep air virtual (virtual water) hadir sebagai salah satu alternatif konsep berserta alat hitung air yang diperlukan dalam sebuah proses produksi pertanian. Penelitian ini dilakukan untuk mengidentifikasi air virtual untuk komoditas padi, jagung, dan kedelai di wilayah Daerah Istimewa Yogyakarta. Analisa dalam penelitian ini menghasilkan nilai tapak air yang terdiri dari blue water, green water, dan grey water. Hasil penelitian menunjukkan, bahwa water footprint tahunan kedelai merupakan yang tertinggi dengan 2.589 m3/ton disusul padi ladang, jagung, dan padi sawah sebesar 1.280 m3/ton; 844 m3/ton; 841 m3/ton. Hasil ini disebabkan oleh tingkat produktivitas yang semakin tinggi nilainya maka akan menghasil nilai water footprint akan semakin rendah. Pelaksanaan penelitian ini mengungkap faktor yang mempengaruhi jumlah air yang diperlukan untuk memproduksi komoditas pertanian. Pemilihan lokasi, kondisi iklim, jenis tanaman, teknik budidaya hingga penggunaan pupuk merupakan faktor yang perlu diperhatikan untuk dapat menekan penggunaan air dalam proses produksi pertanian. Dengan demikian, tujuan pelaksanaan budidaya pertanian yang berkelanjutan dapat terwujud.

Download Full-text

Analysis of virtual water flows associated with the trade of maize in the SADC region: importance of scale

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-5-2727-2008 ◽

2008 ◽

Vol 5 (5) ◽

pp. 2727-2757 ◽

Cited By ~ 3

Author(s):

J. M. Dabrowski ◽

E. Masekoameng ◽

P. J. Ashton

Keyword(s):

South Africa ◽

Water Use Efficiency ◽

Water Content ◽

Water Use ◽

Water Scarcity ◽

Virtual Water ◽

Blue Water ◽

Maize Production ◽

Water Flows ◽

Use Efficiency

Abstract. The concept of virtual water encourages a country to view agricultural crops in terms of the amount of water required to produce those crops, with a view to implementing trading policies that promote the saving of scarce water resources. Recently, increased attention has focussed on partitioning the virtual water content of crops into green and blue water (derived from rainfall and irrigation, respectively) as the latter has higher opportunity costs associated with its use and therefore impacts directly on scarcity. Maize is the most important crop traded within the SADC region. South Africa is the largest producer and exporter of maize, with the majority of its exports destined for other SADC countries. In comparison to other SADC countries, South Africa produces maize relatively efficiently, with a low virtual water content and a high green (868 m3 tonne−1) to blue (117 m3 tonne−1) water ratio. The blue water content is however higher than for maize produced in all other SADC countries, with the exception of Namibia (211 m3 tonne−1). Current trade patterns therefore result in a net expenditure of blue water (66×106 m3), almost all of which is exported by South Africa (65×106 m3). South Africa is one of the most water scarce countries in the region and analysis of virtual water flows indicates that current SADC maize trading patterns are influenced by national productivity as opposed to water scarcity. The virtual water content of maize was estimated for each of South Africa's nineteen Water Management Area's (WMA) and used as a proxy to represent water use efficiency for maize production. The virtual water content varied widely across all of the WMAs, ranging from 360 m3 tonne-1 in the Ustutu Mhlatuze to 1000 m3 tonne−1 in the Limpopo. A comparison of the virtual water content and production of maize (expressed as a percentage of the total national production) identified those WMAs where maize production is highly water inefficient (e.g. Lower Orange and Limpopo WMAs). Results suggest that, while a national estimate of the virtual water content of a crop may indicate a relatively efficient use of water, an analysis of the virtual water content at smaller scales can reveal inefficient use of water for the same crop. Therefore, analysis of the virtual water content of crops and trading of agricultural products at different spatial scales (i.e. regional, national and WMA) could be an important consideration within the context of water allocation, water use efficiency and alleviation of water scarcity.

Download Full-text

Water saving through international trade of agricultural products

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-2-2219-2005 ◽

2005 ◽

Vol 2 (6) ◽

pp. 2219-2251 ◽

Cited By ~ 3

Author(s):

A. K. Chapagain ◽

A. Y. Hoekstra ◽

H. H. G. Savenije

Keyword(s):

Water Resources ◽

Water Use ◽

Virtual Water ◽

Water Saving ◽

Agricultural Products ◽

Green Water ◽

Blue Water ◽

Water Flows ◽

Global Water ◽

National Water

Abstract. Many nations save domestic water resources by importing water-intensive products and exporting commodities that are less water intensive. National water saving through the import of a product can imply saving water at a global level if the flow is from sites with high to sites with low water productivity. The paper analyses the consequences of international virtual water flows on the global and national water budgets. The assessment shows that the total amount of water that would have been required in the importing countries if all imported agricultural products would have been produced domestically is 1605 Gm3/yr. These products are however being produced with only 1253 Gm3/yr in the exporting countries, saving global water resources by 352 Gm3/yr. This saving is 28% of the international virtual water flows related to the trade of agricultural products and 6% of the global water use in agriculture. National policy makers are however not interested in global water savings but in the status of national water resources. Egypt imports wheat and in doing so saves 3.6 Gm3/yr of its national water resources. Water use for producing export commodities can be beneficial, as for instance in Cote d'Ivoire, Ghana and Brazil, where the use of green water resources (mainly through rain-fed agriculture) for the production of stimulant crops for export has a positive economic impact on the national economy. However, export of 28 Gm3/yr of national water from Thailand related to rice export is at the cost of additional pressure on its blue water resources. Importing a product which has a relatively high ratio of green to blue virtual water content saves global blue water resources that generally have a higher opportunity cost than green water.

Download Full-text

Spatial Characteristics and Implications of Grey Water Footprint of Major Food Crops in China

Water ◽

10.3390/w11020220 ◽

2019 ◽

Vol 11 (2) ◽

pp. 220 ◽

Cited By ~ 1

Author(s):

Lin Wang ◽

Yutong Zhang ◽

Ling Jia ◽

Guiyu Yang ◽

Yizhen Yao ◽

...

Keyword(s):

Water Resources ◽

Water Footprint ◽

Water Environment ◽

Sustainable Use ◽

Northwest China ◽

Application Rate ◽

Green Water ◽

Blue Water ◽

Grey Water ◽

Fertilizer Application Rate

The estimated, effective increase of agricultural fertilizer applied in China by 10.57 Mts from 2006 to 2016 is a crucial factor affecting the water environment. Based on analyzing the nitrate-leaching rate, the nitrogen-fertilizer application rate, and crop yield in wheat and maize key cultivation divisions in China, this paper applied the grey water footprint analytical method to estimate THE grey water footprint and its proportion to total water footprint and analyzed the spatial differences from 2012 to 2016. Results showed that the grey water footprint of wheat was higher in North and Northwest China with an increasing trend, while that of maize was higher in Southwest and Northwest China because of high nitrogen application rates and low yields in these regions. Except for the Southwestern division, wheat’s grey water footprint was about 1.3 times higher than the blue water footprint, while, for maize, it was two to three times higher. When analyzing and planning water demand for crop irrigation, the water required for nonpoint source pollution due to chemical fertilizers should be considered. Focusing blue water (irrigation) alone, while neglecting green water and ignoring grey water footprints, it might lead to overestimation of available agricultural water resources and failure to meet the goals of sustainable use of water resources.

Download Full-text

A step forward toward the high-resolution assessment of virtual water flows at the company’s scale

10.5194/egusphere-egu21-14900 ◽

2021 ◽

Author(s):

Elena De Petrillo ◽

Marta Tuninetti ◽

Francesco Laio

Keyword(s):

Water Management ◽

High Resolution ◽

Water Resources ◽

Virtual Water ◽

The State ◽

Green Water ◽

Blue Water ◽

Food Trade ◽

Water Flows ◽

Final Consumer

Through the international trade of agricultural goods, water resources that are physically used in the country of production are virtually transferred to the country of consumption. Food trade leads to a global redistribution of freshwater resources, thus shaping distant interdependencies among countries. Recent studies have shown how agricultural trade drives an outsourcing of environmental impacts pertaining to depletion and pollution of freshwater resources, and eutrophication of river bodies in distant producer countries. What is less clear is how the final consumer &#8211; being an individual, a company, or a community- impacts the water resources of producer countries at a subnational scale. Indeed, the variability of sub-national water footprint (WF in m3/tonne) due to climate, soil properties, irrigation practices, and fertilizer inputs is generally lost in trade analyses, as most trade data are only available at the country scale. The latest version of the Spatially Explicit Information on Production to Consumption Systems model&#160; (SEI-PCS) by Trase provides detailed data on single trade flows (in tonne) along the crop supply chain: from local municipalities- to exporter companies- to importer companies &#8211; to the final consumer countries. These data allow us to capitalize on the high-resolution data of agricultural WF available in the literature, in order to quantify the sub-national virtual water flows behind food trade. As a first step, we assess the detailed soybean trade between Brazil and Italy. This assessment is relevant for water management because the global soybean flow reaching Italy may be traced back to 374 municipalities with heterogeneous agricultural practises and water use efficiency. Results show that the largest flow of virtual water from a Brazilian municipality to Italy -3.52e+07 m3 (3% of the total export flow)- comes from Sorriso in the State of Mato Grosso. Conversely, the highest flow of blue water -1.56e+05 m3- comes from Jaguar&#227;o, in the State of Rio Grande do Sul, located in the Brazilian Pampa. Further, the analysis at the company scale reveals that as many as 37 exporting companies can be identified exchanging to Italy; &#160;Bianchini S.A is the largest virtual water trader (1.88 e+08 m3 of green water and 3,92 e+06 m3 of blue water), followed by COFCO (1,06 e+08 m3 of green water and 6.62 m3 of blue water) &#160;and Cargill ( 6.96 e+07 m3 of green water and 2.80 e+02 m3 of blue water). By building the bipartite network of importing companies and municipalities originating the fluxes we are able to efficiently disaggregate the supply chains , providing novel tools to build sustainable water management strategies.

Download Full-text

A spatially detailed blue water footprint of the United States economy

Hydrology and Earth System Sciences ◽

10.5194/hess-22-3007-2018 ◽

2018 ◽

Vol 22 (5) ◽

pp. 3007-3032 ◽

Cited By ~ 16

Author(s):

Richard R. Rushforth ◽

Benjamin L. Ruddell

Keyword(s):

United States ◽

Water Use ◽

Water Footprint ◽

Virtual Water ◽

The United States ◽

Energy Information Administration ◽

Blue Water ◽

Consumptive Use ◽

The Us ◽

Per Capita

Abstract. This paper quantifies and maps a spatially detailed and economically complete blue water footprint for the United States, utilizing the National Water Economy Database version 1.1 (NWED). NWED utilizes multiple mesoscale (county-level) federal data resources from the United States Geological Survey (USGS), the United States Department of Agriculture (USDA), the US Energy Information Administration (EIA), the US Department of Transportation (USDOT), the US Department of Energy (USDOE), and the US Bureau of Labor Statistics (BLS) to quantify water use, economic trade, and commodity flows to construct this water footprint. Results corroborate previous studies in both the magnitude of the US water footprint (F) and in the observed pattern of virtual water flows. Four virtual water accounting scenarios were developed with minimum (Min), median (Med), and maximum (Max) consumptive use scenarios and a withdrawal-based scenario. The median water footprint (FCUMed) of the US is 181 966 Mm3 (FWithdrawal: 400 844 Mm3; FCUMax: 222 144 Mm3; FCUMin: 61 117 Mm3) and the median per capita water footprint (FCUMed′) of the US is 589 m3 per capita (FWithdrawal′: 1298 m3 per capita; FCUMax′: 720 m3 per capita; FCUMin′: 198 m3 per capita). The US hydroeconomic network is centered on cities. Approximately 58 % of US water consumption is for direct and indirect use by cities. Further, the water footprint of agriculture and livestock is 93 % of the total US blue water footprint, and is dominated by irrigated agriculture in the western US. The water footprint of the industrial, domestic, and power economic sectors is centered on population centers, while the water footprint of the mining sector is highly dependent on the location of mineral resources. Owing to uncertainty in consumptive use coefficients alone, the mesoscale blue water footprint uncertainty ranges from 63 to over 99 % depending on location. Harmonized region-specific, economic-sector-specific consumption coefficients are necessary to reduce water footprint uncertainties and to better understand the human economy's water use impact on the hydrosphere.

Download Full-text

The water footprint of Indonesian provinces related to the consumption of crop products

Hydrology and Earth System Sciences ◽

10.5194/hess-14-119-2010 ◽

2010 ◽

Vol 14 (1) ◽

pp. 119-128 ◽

Cited By ~ 87

Author(s):

F. Bulsink ◽

A. Y. Hoekstra ◽

M. J. Booij

Keyword(s):

Water Use ◽

Water Scarcity ◽

Water Footprint ◽

Virtual Water ◽

Grey Water ◽

Water Flows ◽

External Water ◽

Water Scarce ◽

Water Accounts ◽

National Water

Abstract. National water use accounts are generally limited to statistics on water withdrawals in the different sectors of economy. They are restricted to "blue water accounts" related to production, thus excluding (a) "green" and "grey water accounts", (b) accounts of internal and international virtual water flows and (c) water accounts related to consumption. This paper shows how national water-use accounts can be extended through an example for Indonesia. The study quantifies interprovincial virtual water flows related to trade in crop products and assesses the green, blue and grey water footprint related to the consumption of crop products per Indonesian province. The study shows that the average water footprint in Indonesia insofar related to consumption of crop products is 1131 m3/cap/yr, but provincial water footprints vary between 859 and 1895 m3/cap/yr. Java, the most water-scarce island, has a net virtual water import and the most significant external water footprint. This large external water footprint is relieving the water scarcity on this island. Trade will remain necessary to supply food to the most densely populated areas where water scarcity is highest (Java).

Download Full-text