Effects of climate change on paddy water use efficiency with temporal change in the transplanting and growing season in South Korea

摘要

The aim of this study was to assess the effects of climate change on green and blue water use with temporal change in the transplanting and growing season for paddy fields in South Korea using the representative concentration pathway (RCP) 4.5 and 8.5 scenarios in 2025 (2011-2040), 2055 (2041-2070), and 2085 (2071-2100). The optimal transplant date determined by an accumulated temperature analysis, between 27 April and 21 May in 1995, was delayed until 29 June in 2085, and the average growing period was decreased by about 20 days in 2085. Changes in the transplanting season and growing period could influence the efficiency of future green water use and blue water savings. Approximately 810.5 Mm(3) of green water was available during the 1995 transplanting season, but the predicted use of green water was 1524.7 Mm(3) in future for the optimal transplanting season. In addition, 923.0 Mm(3) of blue water savings can be expected in 2025. This study showed that appropriate change of transplanting season could mitigate the water requirements in paddy fields by optimizing phenology, improving green water efficiency, and blue water savings.