Analysis of design water requirement of paddy rice using frequency analysis affected by climate change in South Korea

Agricultural industry is directly affected by climatic conditions and changes; therefore, it is essential to understand the effects of climate change on agricultural water resources and to minimize negative effects on stable and sustainable crop production. In South Korea, very little research has been conducted on design water requirements (DWR) of paddy rice, which is a key part of the design and operation of agricultural water resources systems. This study aims to simulate climate data based on SRES A1B, A2 and B1 scenarios and analyze the DWR of paddy rice in South Korea using frequency analysis methods as affected by climate change. Average changes of the DWR in eight agro-climatic zones were compared to baseline period and results were −2.7% (2025s), −2.2% (2055s), and 2.5% (2085s) for the A1B scenario, −0.7% (2025s), −0.1% (2055s) and −0.7% (2085s) for the A2 scenario, and −1.0% (2025s), 2.0% (2055s) and −1.6% (2085s) for the B1 scenario. The change rates of total paddy water demand (PWD) for the three scenarios ranged between −2.7% and 2.7% for the A1B, −1.0% and 0.0% for the A2, and −1.3% and 2.4% for the B1. In both the PWD and DWR cases, the change rates were below 3%. Trends in the DWR changes of the temporal and spatial distribution were estimated from climate changes. The results of this study can be used as basic data for the development of agricultural water resources, which will contribute to the establishment of counter-measures for droughts and agricultural water policies in the future.

► We analyzed design water requirement (DWR) of paddy rice considering climate change.
► Trends in DWR changes were analyzed under A1B, A2 and B1 scenarios during 2011–2100.
► DWR change rates in all scenarios were within 3% in comparison to the baseline.
► The reason could be the offset effect between ETc and effective rainfall changes.
► Spatial difference in DWR can be utilized in water resources planning and management.