Estimation of the international virtual water flow of grain crop products in Korea

The Korean 2008 self-sufficiency rate for grain was only 26.2%. Because of this, the quantity virtual water (VW) for crop product imports is much greater than that of other countries. International VW trade is especially important to Korea due to its dependency on foreign imports to maintain food security and to establish an agricultural water resource policy. Using international crop products trade statistics during 2003–2007, this study analyzed the virtual water content (VWC) and international virtual water flow (VWF) of major crops. The national water savings and global water savings were also estimated. Major grain products, including 28 products made from 13 crops, were selected for the analysis, based on the net import and export of products totaling more than 10,000 tons. VWCs were computed for the selected major crop products using the VWC of the primary crop of Korea. International VWFs were estimated using the VWC of each crop products. The amount of imported VW was 16,804 and 226 M m3 was exported, so that the net imported VW was 16,578 M m3. VW import is concentrated in wheat, rice, maize (corn), and soybean crops. A small number of countries, including the USA, China, Brazil, etc., account for over 96% of the imported VW, indicating Korea’s heavy dependence on these countries. The average national water savings for Korea and the average global water savings according to crop were estimated using VW flow from international crop products trade during 2003–2007. The estimate of national water savings was 23,870.3 M m3. Three major crops, namely wheat, maize and soybean, account for 95.3% of this total VW saving. Global water savings from the VW trade amounted to 7,253.0 M m3. Korea depends heavily on VW imports concentrated in specific crops and which are primarily imported from a particular set of countries. This indicates that Korea is vulnerable to disruptions in the international grain harvest such as those caused by natural disasters such as floods and drought. Any such disruption could easily become a critical issue for governmental planners who establish food and water supply policies for Korea.