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| Titel |
Assessing blue and green water utilisation in wheat production of China from the perspectives of water footprint and total water use |
| VerfasserIn |
X. C. Cao, P. T. Wu, Y. B. Wang, X. N. Zhao |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 8 ; Nr. 18, no. 8 (2014-08-25), S.3165-3178 |
| Datensatznummer |
250120443
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| Publikation (Nr.) |
 copernicus.org/hess-18-3165-2014.pdf |
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| Zusammenfassung |
| The aim of this study is to estimate the green and blue water footprint (WF)
and the total water use (TWU) of wheat crop in China in both irrigated
and rainfed productions. Crop evapotranspiration and water evaporation loss
are both considered when calculating the water footprint in irrigated
fields. We compared the water use for per-unit product between irrigated and
rainfed crops and analyzed the relationship between promoting the yield and
conserving water resources. The national total and per-unit-product WF of
wheat production in 2010 were approximately 111.5 Gm3 (64.2% green
and 35.8% blue) and 0.968 m3 kg−1, respectively. There is
a large difference in the water footprint of the per-kilogram wheat product (WFP) among different provinces: the WFP is low in
the provinces in and around the Huang–Huai–Hai Plain, while it is relatively
high in the provinces south of the Yangtze River and in northwestern China. The
major portion of WF (80.9%) comes from irrigated farmland, and the
remaining 19.1% is rainfed. Green water dominates the area south of the
Yangtze River, whereas low green water proportions are found in the
provinces located in northern China, especially northwestern China. The
national TWU and total water use of the per-kilogram wheat product (TWUP)
are 142.5 Gm3 and 1.237 m3 kg−1, respectively, containing
approximately 21.7% blue water percolation (BWp). The values of WFP
for irrigated (WFPI) and rainfed (WFPR) crops are 0.911
and 1.202 m3 kg−1, respectively. Irrigation plays an important role in
food production, promoting the wheat yield by 170% and reducing the WFP
by 24% compared to those of rainfed wheat production. Due to the low
irrigation efficiency, more water is needed per kilogram in irrigated
farmland in many arid regions, such as the Xinjiang, Ningxia and Gansu
Provinces. We divided the 30 provinces of China into three categories
according to the relationship between the TWUPI (TWU for per-unit
product in irrigated farmland) and TWUPR (TWU for per-unit product in
rainfed farmland): (I) TWUPI < TWUPR,
(II) TWUPI = TWUPR, and (III) TWUPI > TWUPR. Category II, which
contains the major wheat-producing areas in the North China Plain, produces
nearly 75% of the wheat of China. The double benefits of conserving water
and promoting production can be achieved by irrigating wheat in Category I
provinces. Nevertheless, the provinces in this category produce only 1.1%
of the national wheat yield. |
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