Coupled Irrigation–Drainage Management Practice for HYV Rice Cultivation with Saline-Irrigation Water: Evidence from Lysimeter Experiment

Abstract

Irrigation with saline water adversely affects rice production and degrades land productivity in the coastal zones of many countries in the world. This study aimed at developing a suitable irrigation management practice to reduce the harmful effects of salinity on rice production under saline water irrigation. An experiment in raise-bed lysimeters was set in a split-split-plot design with irrigation–drainage practice as the main factor, irrigation water salinity as the sub-factor and rice variety as sub-sub factor; the main factor and sub-factor comprised four treatments and the sub-sub factor comprised three treatments, each with three replications. The treatments of the main factor were – T1: 2−5 cm continuous ponding, T2: continuous saturation, T3: changing irrigation water after 3 days of application by maintaining 2−5 cm ponding depth, and T4: changing irrigation water after 5 days of application by maintaining 2−5 cm ponding depth. The sub-factor comprised – SL1: fresh water as control, SL2: saline water of 6 dS m−1, SL3: saline water of 9 dS m−1, and SL4: saline water of 12 dS m−1. The sub-sub factor comprised three salt-tolerant rice varieties V1: Binadhan-8, V2: Binadhan-10, and V3: BRRI dhan-47. The irrigation–drainage practices T2 and T3 provided significantly (p≤0.05) improved growth and yield attributes of the rice varieties under salinity water level SL3 and SL4 compared to T1 and T4 treatments. The treatment T3 maintained least exposure of the crop to high degree of salinity and produced satisfactory plant attributes by inhibiting the detrimental effects of salinity. Therefore, T3 is suggested for adoption in practical fields when provision for removing high saline water from the rice fields can be arranged.