Aims <p>Soil salinization critically threatens global agricultural productivity and land sustainability. Although salt-tolerant plants like <i>Zoysia macrostachya</i> show promise for saline land reclamation, their growth is severely inhibited by high salinity. With few solutions addressing both plant stress and soil degradation, this study introduces a novel amendment strategy to enhance turfgrass resilience and restore soil quality in saline environments.</p> Methods <p>A unique amendment system combining rice husk-derived biochar with a custom-synthesized Si/K nutrient solution was developed and applied to <i>Z. macrostachya</i> grown under high salinity (≥ 23.44 dS/m, EC). Plant physiological and transcriptomic responses and antioxidant enzyme activities were assessed, alongside changes in soil physicochemical properties and microbial communities.</p> Results <p>The biochar-Si/K treatment significantly improved plant growth and salt tolerance. Treated plants exhibited a 127.8% increase in chlorophyll content, enhanced antioxidant activity, and a 54.2% reduction in oxidative damage. Ion homeostasis was restored, with improved K⁺/Na⁺ ratios ranging from 3.17 to 23.92. Transcriptomics revealed the upregulation of genes involved in stress signaling and ion transport. Furthermore, soil structure improved with a 52.8% reduction in bulk density and a 12-fold increase in organic matter, while shifts in the microbiome, including an increased abundance of <i>Gemmatimonadota</i>, suggested enhanced nutrient cycling and soil resilience.</p> Conclusions <p>This novel biochar-Si/K amendment strategy provides a sustainable solution for enhancing plant salt tolerance and restoring saline soils. These findings advance understanding of integrated plant-soil responses and hold promise for ecological restoration and agricultural productivity in salt-affected environments.</p> Graphic Abstract <p></p>