Abstract Soil salinity critically threatens agricultural sustainability, particularly in squash production. This study evaluates integrated soil-plant strategies to mitigate salt stress, applying biochar-modified sulfur (BMS) as a soil amendment and licorice root extract (LRE) as a foliar treatment to enhance soil functionality and plant osmotic resilience. Two field experiments (2023–2024) employed a split-plot in randomized complete block design. Main plots tested BMS at 0 (BMS₀), 5 (BMS₅), and 10 (BMS₁₀) ton ha⁻¹; subplots received foliar LRE at 0% (LRE₀) or 1% (LRE₁). BMS₅ and BMS₁₀ significantly ameliorated key physicochemical constraints of saline soils: reducing bulk density, saturated hydraulic conductivity, electrical conductivity (ECe), and pH, while increasing soil-water retention capacity, soil porosity, available water content, organic matter content, cation exchange capacity and nutrient availability (nitrogen, phosphorus and potassium) versus BMS₀. Synergistic BMS + LRE₁ treatments enhanced squash growth metrics, photosynthetic pigments, nutritional and water status, membrane integrity, and yield over (BMS₀ + LRE₀). However, leaf proline, phenolics, free amino acids and TSS were significantly reduced, under the same treatments, confirming improved salinity tolerance of squash plants. Combined BMS and LRE application sustainably enhances saline soil properties and fortifies plant biochemical resilience, optimizing squash productivity. This strategy offers a viable pathway for saline soil management in water-scarce agroecosystems.
Abdou et al. (Fri,) studied this question.