Predicting Climate Change Impact on Water Productivity of Irrigated Rice in Malaysia Using FAO-AquaCrop Model

Abdusslam A Houma,Md Abdul Mojid,Balqis Mohamed Rehan,Mohamed Azwan Mohamed Zawawi,Md Rowshon Kamal

doi:10.3390/app112311253

Abdusslam A Houma, Md Abdul Mojid + Show 3 more

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https://doi.org/10.3390/app112311253

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Abstract

Water productivity (WP) is a key indicator of agricultural water management, since it affects the quantity of water used for crop yield in various management scenarios. This study evaluated the WP of irrigated rice due to a changing climate in the Northwest Selangor Rice Irrigation Scheme (NSRIS) by using field experimental data and the FAO-AquaCrop Model. Pertinent soil, water, climate, and crop data were acquired by executing a field investigation during the off-season (dry season, January–April) and main season (wet season, July–October) in 2017. The AquaCrop 6.0 model was calibrated and validated using the measured data. A Climate-smart Decision Support System (CSDSS) with an ensemble of 10 Global Climate Models (GCMs) was used to downscale climate variables under RCP4.5, RCP6.0, and RCP8.5 emission scenarios during baseline (1976 to 2005) and future (2020 to 2099) periods. The AquaCrop model fairly predicted rice yields under field conditions with root-mean-square error (RMSE), mean absolute error (MAE), prediction error (PE) and index of agreement (d) between the observed and estimated yields of 0.173, 0.157, −0.31 to 5.4 and 0.78, respectively for the off-season; and 0.167, 0.127, −5.6 to 2.3 and 0.73, respectively for the main season. It predicted a 10% decrease in actual crop evapotranspiration (ETc) in both crop seasons in the future. The WP of rice based on total water input (WPIrr+RF), applied irrigation (WPIrr), and actual crop evapotranspiration (WPETc) will likely increase by 14–24%, 14–19%, and 17–29%, respectively under the three RCP emission scenarios in the off-season. The likely increase in WP for the corresponding base is 13–22%, 15–24%, and 14–25% in the main season. Various agronomic management options linked to WP will most likely become important in making crucial decisions to cope with the risk of impacts on climate change.

Highlights

Climate change and weather variability are serious threats to agriculture globally
Downscaled ensemble climate variables using Climate-smart Decision Support System (CSDSS) together with field experimental data and recommended model parameters were used as inputs to AquaCrop model, and rice yield and water productivity (WP) indicators were simulated for 2010–2039, 2040–2069, and 2070–2099 future periods relative to the
The simulated increasing trend of Water productivity (WP) with increasing CO2 concentration, temperature, and rainfall under RCP4.5, RCP6.0, and RCP8.5 emission scenarios indicates an improved synergy for rice growth under the projected water-heat-carbon status

Summary

Introduction

Climate change and weather variability are serious threats to agriculture globally. The scientific community has become certain that the modified climatic signals will likely exert significant impacts on crop production functions, with an eventual threat to global food security for the growing population [1,2]. A study [5] in Peninsular Malaysia examined the impact of climate change on river flows at 10 watersheds’ outlets and 12 coastal regions. According to [5], the increase in 30-year mean annual precipitation from 1970 to 2070–2100 will vary between 17.1% and 36.3% among the watersheds, and between 22.9% and 45.4% among the coastal regions. There will be a 2.52 ◦ C to 2.95 ◦ C increase in the ensemble average of the basin-average annual mean air temperature between the years 2010 and 2100 [5]

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