Simulating Water Use Demandsfor Rice Planting Crops under the Impacts of Climate Change: A Case Study for AnGiang Province, Vietnam

Abstract

An Giang province is one of the key agricultural areas in the Mekong Delta of Vietnam and has an important contribution in term of food security and economic development in Vietnam. In recent years, this area has seriously impacted by drought due to the impact of climate change leading to the irrigation water scarce. Therefore, the accurate prediction of water use demand (WUD) and establish irrigation schedules to irrigate right time and enough water volume are very necessary, especially in the context of climate variability. The aim of this study, therefore, was conducted applying the CropWat model based on meteorological factors which collected in the period (2010-2018) to estimate WUD and establish irrigation scheduling for winter-spring, summer-autumn and autumn-winter planting crops order to provide necessary information in improving irrigation practices, helping decisions on irrigation management under the impacts of climate variability. The results showed that the WUD of the three planting crops varied from 0.0 to 176.8 mm/decade, of which the highest WUD (827.8 mm) recorded in the winter-spring planting crop while the lowest (236.3 mm) observed in the autumn-winter planting crop. The highest WUD of winter-spring, summer-autumn planting crops was occurred in the stage from the mid-second decade to the end of the third decade and decliningclose to zero on the four decade to the mid-sixth decade of the autumn-winter planting crop. The results also showed that the highest irrigation conditions occurred in the development stage with the rates approximately 37.67%, 48.9% and 48.2%, respectively total of irrigation water amount corresponding to winter-spring, summer-autumn and autumn-winter planting crops.