Soil salinization is a major challenge affecting crop yield in arid and semi-arid regions. Amendments to agricultural soil under drip irrigation represent a potential strategy to ameliorate soil salinization. This study conducted a field experiment over two years to identify the impacts of desulfurized gypsum, biochar, and straw on sunflower yield and soil characteristics in salinized and alkalized soil. Soil amelioration significantly improved soil characteristics by reducing saline–alkali stress at a 0–15 cm soil depth. Increased and decreased surface soil moisture and density of soil bulk were achieved by the second year, respectively, through the application of straw and biochar. These soil amendments also significantly decreased soil electrical conductivity and pH, and the application of biochar significantly reduced the sodium adsorption ratio (SAR refers to the adsorption ratio of sodium ions to other ions in soil) and Na+ by 32.1% and 34.7%, respectively, compared with drip irrigation alone. Application of desulfurized gypsum combined with drip irrigation decreased soil pH, SAR, and Na+ by 0.25, 41.6%, and 38.1%, respectively, compared with drip irrigation alone. The three soil amendments significantly increased sunflower yields by 51.2–80.0% in the second year, with the biochar treatment showing the most significant impact. The results showed that combined biochar and drip irrigation could play an important role in ameliorating soil salinization in the Hetao Irrigation Area, thereby contributing to increased crop yields and sustainable agriculture. However, given the relatively short experimental duration and the single location of this study, as well as the lack of long-term monitoring of salt balance and drainage conditions, further research with extended timelines, expanded geographic coverage, and focused assessment of salt dynamics is needed to confirm and generalize these findings.
Lan et al. (Tue,) studied this question.