Impact of Sesbania sesban (L.) Merr. Cultivation on the Physicochemical Properties of Salt‐Affected Soils

Soil salinity is a major constraint to agricultural productivity and ecosystem sustainability in arid and semiarid regions, particularly in Iraq, where extensive areas are salt‐affected. This study assessed Sesbania sesban (L.) Merr. as a biological reclamation crop for improving saline soil properties under field conditions in Tarmiyah District, north of Baghdad, using a 2 × 2 factorial design (saline and agricultural soils; vegetated and nonvegetated treatments) during the 2025 growing season. Results revealed that S. sesban markedly reduced soil salinity and sodicity, with electrical conductivity (EC) decreasing by 79.8% in saline soil and 77.0% in agricultural soil, Na + by 89.1% and 78.2%, Cl − by 88.6% and 85.7%, and sodium adsorption ratio (SAR) by 77.6% and 58.9%, respectively, indicating efficient desalination and ion removal. In parallel, soil organic matter increased substantially by 296.7% and 325.4%, reflecting enhanced organic inputs and rhizosphere activity, while nitrogen declined by 31.8% and 74.1% due to net uptake under short‐term cultivation. Phosphorus showed minor increases (2.0%–5.6%), whereas potassium exhibited contrasting trends, decreasing in saline soil (−4.9%) but increasing in agricultural soil (+29.2%), highlighting salinity‐dependent nutrient dynamics. Soil pH and texture remained stable, confirming strong buffering capacity. Although salinity significantly suppressed plant performance—reducing stem length (−33.9%), root length (−24.3%), leaf number (−29.9%), and nodulation (−85.7%)—plants maintained functional growth and partial symbiotic activity, demonstrating notable salt tolerance. Overall, S. sesban operates as an integrated phytoremediation agent that simultaneously reduces salinity and enhances soil fertility through coupled physical, chemical, and biological mechanisms, supporting its application in sustainable reclamation of salt‐affected soils.