Optimization and characterization of a soil mix to mitigate hardpan formation during germination under saline conditions

Aim To assess the combined effects of different coco-peat incorporation ratios and graded NaCl salinity levels on the physico-chemical properties of clayey loam soil and the early growth responses of wheat (Triticum aestivum), with special emphasis on mitigating soil compaction and hardpan formation during germination. Methods A pot experiment was conducted using clayey loam soil amended with varying ratios of coco-peat and exposed to graded NaCl concentrations. Key soil physico-chemical parameters, including electrical conductivity (EC), pH, bulk density, particle density, porosity, soil moisture content, and water holding capacity, were measured. Seed germination performance and root architectural traits were also evaluated to determine early plant responses under combined treatments. Results Coco-peat incorporation significantly improved soil structure by increasing porosity, moisture retention, and water holding capacity, while reducing bulk density. These changes enhanced soil aeration and water movement even under saline conditions. Consequently, wheat seeds showed improved germination, and root systems exhibited better growth and development compared to non-amended saline soils. Conclusion Coco-peat can effectively alleviate the negative physical impacts of salinity by reducing soil compaction and minimizing hardpan formation during early crop establishment. The study also provides a practical approach for creating uniform and controlled salinity conditions in pot experiments, enabling more reliable assessment of plant responses to salt stress.