A dual hydraulic–microbial irrigation toolkit for precision root-zone hydration in date palm

Sustainable irrigation of Phoenix dactylifera L. in the Middle East and North Africa (MENA) region remains challenged by extreme evaporative demand, poor soil water retention and significant drainage losses from conventional surface system. In this study, an integrated irrigation toolkit combining a buried diffuser subsurface irrigation device with a desert saline-adapted synthetic microbial consortium (SynCom) was evaluated to optimize root-zone hydration, plant growth, and rhizosphere microbiome function. The performance of this toolkit was examined under full and deficit irrigation (100% ETc and 50% ETc), with comparison to conventional surface bubbler irrigation, focusing on plant water status, soil moisture fluctuation, and shifts in the root–soil microbiome of date palm. Among the irrigation methods evaluated, the buried diffuser enhanced plant performance when compared to conventional surface bubbler irrigation. Under deficit irrigation, buried diffuser increased plant growth by 75% relative to conventional surface bubbler system without SynCom and nearly doubled plant biomass. Enhanced plant performance was associated with higher leaf water content and substantially lower oxidative stress markers compared with conventional surface irrigation treatments, indicating a stress avoidance response by plants. Subsurface water delivery through buried diffuser increased soil water content by up to two-fold and reduced leaching losses by approximately 40%, resulting in a 16.3% increase in water productivity relative to conventional surface bubbler irrigation. Improved root development such as thicker endodermis, and well-defined vascular bundles were also observed under the buried diffuser irrigation. SynCom inoculation further enriched specific bacterial groups, particularly Gammaproteobacteria (40%) and Bacilli (27%) in roots and soil. This hydraulic–microbial system provides a solution for improving irrigation efficiency and crop performance in arid horticultural systems.