Organic amendments have considerable potential to improve soil quality and crop productivity, yet their effectiveness varies with amendment type and initial soil conditions. To identify the key factors governing these responses and develop effective strategies for soda saline-alkali soil reclamation, we first conducted a global meta-analysis of 144 studies, covering 153 experimental sites and 1,815 datasets. The results showed that straw, biochar, and organic fertilizer increased crop yields by 27.68%, 38.60%, and 40.35%, respectively, through their complementary roles in carbon input, soil structural improvement, and nutrient supply. Soil organic matter (SOM) and available nitrogen were identified as the primary drivers of yield responses, while amendment effectiveness varied with initial SOM levels. These findings highlighted the importance of soil-specific amendment selection and integrated management. Building on these findings, field experiments were conducted in soybean uplands and rice paddies in Northeast China to evaluate the effectiveness and underlying mechanisms of integrated organic amendment strategies in soda saline-alkali soils. In soybean uplands, combined application of straw, biochar, and organic fertilizer improved soil aggregation, water retention, and salt redistribution. Compared with the control, macroaggregate proportion (>2 mm) increased by 23.2%, while soil pH and exchangeable sodium percentage decreased by 3.19% and 24.2%, respectively. These improvements promoted soybean growth and canopy development. Structural equation modeling further demonstrated that soil structural improvement enhanced yield formation primarily through improved water-holding capacity and alleviation of salt-alkali stress. In rice paddies, coordinated straw-biochar application and optimized nitrogen management reduced soil bulk density by 10.64%, increased total porosity by 12.05%, and increased rice yield by 42.88% under the optimal treatment in 2024. Collectively, the global meta-analysis identified the major drivers and context-dependent responses of organic amendments, while field experiments demonstrated how integrated management could translate these findings into effective soil amelioration and crop productivity improvements. This study provides a scientific basis for developing sustainable and site-specific management strategies for soda saline-alkali soils.

Yang Aizheng is an Associate Professor and Doctoral Supervisor.

His research focuses on the remediation of soil constraints and the enhancement of soil functionality, with particular emphasis on saline-alkali soil improvement, soil water and salt transport, carbon and nitrogen cycling, greenhouse gas emission reduction, and subsurface drainage systems.

He has served as Principal Investigator for more than 10 research projects, including General and Young Scientists Program projects funded by the National Natural Science Foundation of China (NSFC), subprojects under the National Key Research and Development Program of China, and provincial- and ministerial-level research projects. He has published over 40 academic papers, co-authored three Chinese and English monographs, and holds more than 20 authorized invention patents and software copyrights. He has also received two provincial- and ministerial-level scientific and technological awards.