Potential risks of climate variability on rice cultivation regions in the Mekong Delta, Vietnam

Abstract

In recent decades, the rice cultivation regions in the Mekong Delta have continuously suffered from unprecedented weather events due to a decline in rainfall as part of climate variability. The aim of this study was to perform a comprehensive exploration of the rainfall characteristics across the area, applying the Rainfall Anomaly Index (RAI), Spearman Rho test and Sen slope estimator to help track the weather as well as provide warnings on the potential risks caused by alterations in rainfall amounts. For this goal, the rainfall data sequences at 14 national observation stations across the Mekong Delta were collected for the 1984 - 2019 period. Results indicated that the dry weather seasons occurred more frequently during the normally wet weather seasons. Four typical dry weather seasons were identified for the 1997 - 1998, 2002 - 2004, 2014 - 2016, and 2018 - 2019 periods. Among these, the 2014 - 2016 period was the driest, with 9 out of 12 stations in the area being extremely dry and RAI risk peaks as high as -4.86 at the Moc Hoa station in the province of Long An. A weather trend of decreasing rainfall was evident, mainly in the coastal sub-regions. The discovery of changing rainfall trends is valuable for predicting future climate variability.

Cold stress reduces rice grain yield in temperate conditions

“…Farmers use cold-tolerant varieties to protect against cold damage, as this causes the termination of plants in the germination or seedling stages, and seeds have to be resown due to the lack of germination, low germination, or late germination. In some locations, farmers can sow rice seeds in very early periods, such as April 15, to be able to offer crops to the market early and to avoid precipitation at harvest time, depending on changing rainfall trends (Dinh & Dang, 2022). These farmers tend to terminate and resow their fields if the conditions are not good.…”