Physiological and Biochemical Responses of Pearl Millet and Mustard to Cut-Soiler-Based Shallow Subsurface Drainage Under Saline Irrigation

Inadequate drainage and the application of salty irrigation waterinduced salinity stress, poses a major constraint to agricultural productivity, especially in saline–arid regions. Shallow subsurface drainage has emerged as a potential technique for salinity management; however, its implications for crop physiological and biochemical responses remain unclear. Therefore, a two-year lysimetric study was undertaken in a split-split plot design investigating cut-soiler-based preferential shallow subsurface drainage (PSSD), soil type (saline sandy loam and normal silty clay loam), and irrigation water salinity levels (4, 8 and 12 dS m−1) to evaluate the effectiveness of rice-residue-filled cut-soiler PSSD in mitigating salinity stress in pearl millet and mustard crops. The cut-soiler PSSD reduced root-zone salinity to around 60.0% by the end of experimentation. Lower root-zone salinity under cut-soiler PSSD alleviated osmotic and ionic stress by reducing hydrogen peroxide (11.0–14.6%), membrane injury (22.7–40.8%), lipid peroxidation (20.0–25.0%), proline accumulation (26.0–37.0%) and improving the Na+/K+ ratio (44.0%). Antioxidant enzyme activities were also significantly moderated under the cut-soiler PSSD. These physiological and biochemical improvements resulted in significant increases in grain and seed yield of pearl millet (23.5%) and mustard (31.4%), respectively. The findings of this study indicate that cut-soiler PSSD is an effective strategy to mitigate salinity stress at the physiological and biochemical level and offers sustainable management strategies for salt-affected agro-ecosystems.