Abstract
Abstract. 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.
Highlights
China is the most populous and the largest foodconsuming country, it is one of the poorest countries in terms of individual water resources, at only 2100 m3 per capita in 2010 (MWR, 2011), or less than one-quarter of the worldwide water resources per capita (Ge et al, 2011)
By distinguishing between the irrigated and rainfed crops, the contribution of this study is the utilisation of the actual statistical data from typical irrigation districts and the calculation of the crop water footprint and the total water use at the regional scale
The major findings of the current study are as follows: (i) the green water related to China’s wheat production plays a dominant role in the water footprint, while it is roughly equal to the blue water footprint in the total water use; (ii) a large portion of the water footprint is depleted during delivery and cannot be reused during the crop growth period; and (iii) irrigation increases the crop yield and reduces the water footprint per kilogram of wheat product dramatically, indicating that more water resources need to be invested in crop production, leading to the total water per unit of irrigated wheat being greater than that of rainfed crops
Summary
China is the most populous and the largest foodconsuming country, it is one of the poorest countries in terms of individual water resources, at only 2100 m3 per capita in 2010 (MWR, 2011), or less than one-quarter of the worldwide water resources per capita (Ge et al, 2011). With the population surge and socioeconomic development, the water crisis has become a hot spot all over the nation because the gap between increased demands and limited water resources is increasing. Agriculture is the largest water user in China, accounting for more than 60 % of the total water (blue water) withdrawals (MWR, 2011). Cao et al.: Assessing blue and green water utilisation in wheat production of China agriculture to meet the freshwater challenges facing China in the future (Wu et al, 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
