LONG-TERM IMPACT ANALYSIS OF CLIMATE CHANGE ON PADDY IRRIGATION WITH AN AGRICULTURAL DAM

Abstract

 According to the paddy cropping in Japan, no previous studies assess the climate change impacts including the relationship between rice crop growth and water resource availability, nor analyze the change of trends. In this study, by using a combined model of a paddy rice growth model and an agricultural dam model, and climatic data calculated by a 150-year continuous experiment based on the RCP8.5 scenario, the long-term trend analysis in the number of crop growth days, crop yield, dam storage rate, and water stress was conducted in a district in Mie Prefecture. As a result, the increasing trend in crop yield stops around the 2070s, the period with on average small dam water storage becomes earlier as time goes on, and water stress becomes severer. In addition, when the transplanting date is changed as an adaptation measure, although an earlier transplanting date than the current is desirable from the aspect of average yield maximization, a later transplanting date is desirable from the aspect of stable irrigation supply.