Amelioration of Saline‐Sodic Soils by Desulfurized Gypsum and Organic Amendments: From Mechanism to Field Practice

ABSTRACT

Soil salinization poses a major threat to both the global environment and the sustainability of viticulture. This study proposes a synergistic remediation strategy using desulfurized gypsum combined with organic amendments—biochar and lignite. Through integrated incubation, pot, and 2‐year field experiments, we clarify the underlying process mechanisms, focusing on two aspects: enhancing the efficiency of calcium–sodium ion exchange and achieving sustained regulation of soil fertility. The results show that the organic amendments significantly improved the replacement efficiency of sodium ions by calcium ions from the gypsum. They also enhanced soil biochemical activity by promoting organic matter mineralization (e.g., the peak CO ₂ emission increased by 79% compared to the control). In the presence of grapevines, the stability of the calcium‐sodium exchange and soil fertility was maintained through rhizosphere microenvironment regulation and carbon input. Improvements in plant physiological indicators further confirm the systemic optimization of the soil environment. The 2‐year field experiment further confirms the long‐term stability of this strategy. It consistently reduced the soil sodium adsorption ratio (by 49% compared to the control) and salt content (e.g., water‐soluble Na ⁺ decreased by 27%), with no significant secondary salt accumulation observed. Concurrently, the physiological indicators of the grapevines showed lasting improvement. This study demonstrates that the synergistic effect of desulfurized gypsum and organic amendments effectively optimizes the soil ionic composition through calcium‐sodium exchange, while the input of organic materials and micro‐ecological regulation continuously improve soil fertility. Thus, it provides a comprehensive, mechanism‐explicit, and operationally feasible solution for the sustainable management of salinized vineyard soils.