عنوان مقاله
مقدار آب مجازی محصولات غلات اصلی و جریانات آب مجازی بین مناطق در چین
فهرست مطالب
مقدمه
داده ها و روش ها
نتایج
بحث
نتیجه گیری
بخشی از مقاله
VWC سبز و آبی گندم ، ذرت و برنج
آنالیز VWC سبز و آبی برای گندم، ذرت و برنج نشان داد که نسبت آب سبز در هر محصول به تدریج از مناطق شمالی به جنوبی افزایش یافت. تغییرپذیری منطقه ای نسبت آب سبز در VWC بر طبق توزیع بارش در چین بود. مناطقی با بارش فراوان معمولاً دارای نسبت بالایی از آب سبز در VWC محصول هستند.
بر طبق China Water Resources Bulletin ، بارش در مناطق شمالی فقط 51. 31 درصد از کل بارش کشور را به خود اختصاص داد . در مقابل، بارش در مناطق جنوبی 49. 68 درصد از کل بارش در چین را تشکیل می داد. درنتیجه نسبت آب سبز VWC محصول در مناطق جنوبی بالاتر از مناطق شمالی خواهد بود.
کلمات کلیدی:
Research Article Received: 14 April 2012 Revised: 22 August 2012 Accepted article published: 11 September 2012 Published online in Wiley Online Library: 22 November 2012 (wileyonlinelibrary.com) DOI 10.1002/jsfa.5911 The virtual water content of major grain crops and virtual water flows between regions in China Shi-Kun Sun,a,b,c,d Pu-Te Wu,a,b,c∗ Yu-Bao Wangb,c and Xi-Ning Zhaoa,b,c Abstract BACKGROUND: The disproportionate distribution of arable land and water resources has become a bottleneck for guaranteeing food security in China. Virtual water and virtual water trade theory have provided a potential solution to improve water resources management in agriculture and alleviate water crises in water-scarce regions. The present study evaluates the green and blue virtual water content of wheat, maize and rice at the regional scale in China. It then assesses the water-saving benefits of virtual water flows related to the transfer of the three crops between regions. RESULTS: The national average virtual water content of wheat, maize and rice were 1071 m3 per ton (50.98% green water, 49.02% blue water ), 830 m3 per ton (76.27% green water, 23.73% blue water) and 1294 m3 per ton (61.90% green water, 38.10% blue water), respectively. With the regional transfer of wheat, maize and rice, virtual water flows reached 30.08 Gm3 (59.91% green water, 40.09% blue water). Meanwhile, China saved 11.47 Gm3 green water, while it consumed 7.84 Gm3 more blue water than with a no-grain transfer scenario in 2009. CONCLUSION: In order to guarantee food security in China, the government should improve water productivity (reduce virtual water content of crops) during the grain production process. Meanwhile, under the preconditions of economic feasibility and land-water resources availability, China should guarantee the grain-sown area in southern regions for taking full advantage of green water resources and to alleviate the pressure on water resources. c 2012 Society of Chemical Industry Keywords: virtual water content; green water; blue water; virtual water flows; water saving; China INTRODUCTION The amount of water consumed in the production process of a product is defined as its virtual water content (VWC).1,2 Virtual water flow represents the volume of water that is embedded in traded commodities.3 Countries or regions with scarce water resources could import water-intensive products to decrease the pressure on their own water resources. Meanwhile, the virtual water trade could save water globally if a water-intensive product is traded from a region where it is produced with high water productivity to a region with lower water productivity.4 Therefore, the virtual water flow process may prove significant for improving global water use efficiency and alleviating pressure on local water resources.2,5 Since the 1990s, several researchers have estimated the virtual water flows embedded in the importing or exporting of agricultural products between countries or regions.2,6,7 Meanwhile, other studies have stressed that the virtual water trade could alleviate local water scarcity and improve global water use efficiency by importing high water-intensive commodities (like grains) from a country or region that has a low VWC for commodities or abundant water resources.4,5,8–10 Hitherto, most studies of virtual water and virtual water trade have generally been carried out at a global or national scale, thus concealing the regional differences of countries that consist of a wide range of agro-climatic areas.11 At the same time, few studies focus on distinguishing green water (rainwater consumed during the crop production process) and blue water (surface or ground water consumed in crop production) in crop VWC.12–14 The emphasis has been given to blue water in conventional water resources planning and management. However, the use of blue water is restricted by its scarcity, high opportunity cost and large influence on the environment. Meanwhile, this becomes the limiting factor to socio-economic development in water-scarce areas. Green water has sustained the terrestrial ecosystem and rain-fed agriculture worldwide.15,16 In addition, green water generally has a lower opportunity cost and smaller environmental impact.17 Therefore, the significance of green water for agriculture and ecosystem has triggered ∗ Correspondence to: Pu-TeWu, Institute of Soil andWater Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, China. E-mail: gjzwpt@vip.sina.com a Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, China b Institute of Water Saving Agriculture in Arid regions of China, Northwest A & F University, Yangling, China c National Engineering Research Center for Water Saving Irrigation at Yangling, Yangling, China d Graduate University of Chinese Academy of Sciences, Beijing, China
