Improving the economic productivity of limited available freshwater through producing more rice with less water is essential to sustain paddy production systems in the future. The effectiveness of two current-successful water management strategies, i.e., mid-season drainage (MSD) and alternate wetting and drying (AWD), under future climate was investigated for the first time involving the AquaCrop model. The model was calibrated and validated using 4-year field data of an early-matured rice cultivar. Future climate data was downscaled for a 2041-2070 period under two Representative Concentration Pathways (RCP) of RCP2.6 and RCP8.5 by applying 20 different Global Circulation Models. The calibrated AquaCrop was then used to predict yield, water productivity (WP), and economic water productivity (EWP) for different cropping calendars. For the current planting date, global warming will reduce rice yield (70-170 kg ha(-1)), WP (10-15%), and EWP (16-27%) under MSD and increases yield (1040-1290 kg ha(-1)) and decreases WP (21-31%), and EWP (22-32%) under AWD compared with the base period. Delayed cropping could not be a suitable strategy for both MSD and AWD under both climate scenarios. Under MSD and AWD, 10 days earlier transplanting will decrease rice yield by 65-130 kg ha(-1) and WP (and EWP) by 5-11% in RCP2.6, while increasing by 413-820 kg ha(-1) and 8-13% in RCP8.5, respectively. Investigation revealed that sustaining or improving current land and water productivity in the future mainly relies on the severity of global warming. However, the AWD strategy will be a more effective climate change-adaptation strategy than MSD in viewpoints of crop yield, WP, and EWP.
Mirfenderski, R; Darzi-Naftchali, A; Karandish, F
Climate-resilient agricultural water management to alleviate negative impacts of global warming in rice production systems
Theoretical And Applied Climatology