## 1 Introduction  
Currently, the area of soda saline-alkali soil in the Songnen Plain of China exceeds 4.97 \(\times\) 10\({}^{6}\) ha. This region is recognized as one of the three major global concentrations of soda saline-alkali soil [1], primarily located in the provinces of Jilin, Inner Mongolia, and Heilongjiang. The western region of Jilin Province is a crucial base for commodity grain production; however, it is significantly affected by saline-alkali soil. Rice is one of the primary crops cultivated in this area. The presence of saline-alkali soil not only adversely impacts the growth of local rice but also contributes to a shortage of soil suitable for rice-seeedling raising. The key components contributing to soil salinization in saline-alkali soils are sodium carbonate (Na\({}_{2}\)CO\({}_{3}\)) and sodium bicarbonate (NaHCO\({}_{3}\)). The elevated salinity and al kalinity adversely affect soil properties, including aeration and permeability. When the soil-to-water ratio is 5:1, the pH of the surface soil (0-20 cm) can reach 10.16, and the sodium adsorption ratio (SAR) can attain 196.64 (mmol L\({}^{-1}\))\({}^{1}\)/\({}^{2}\)[2]. The significant adsorption of sodium ions (Na\({}^{+}\)) by the soil enhances the hydrophilicity of soil colloids, leading to soil dispersion and structural deterioration. This process limits nutrient availability and reduces soil fertility [3]. The high degree of sodification and low fertility of these soils are major drawbacks that impede their use in rice-seedling raising and other agricultural practices [4]. Farmers in areas with soda saline-alkali soils often utilize mildly saline-alkali soil for simple acid-adjustment treatments as seedbed soil due to a scarcity of suitable soil resources. However, this practice leads to the depletion of soil resources and degradation of the soil environment. Inadequate improvement measures can also harm seedlings and potentially reduce crop yields. Therefore, addressing the issue of soil for rice-seedling raising has become an urgent task. The application of rapidly improved soda saline-alkali soil for rice-seedling raising can enhance the availability of quality seedling-raising soil resources, providing an effective solution to this challenge. Gypsum is one of the most significant and widely utilized amendments for the improvement of saline-alkali soils. It enhances the soil bulk density, hydraulic conductivity, and microporosity [5]. Gypsum ameliorates soda saline-alkali soils by supplying calcium ions (Ca\({}^{2+}\)), which replace excessive monovalent sodium ions (Na\({}^{+}\)) at cation exchange sites within the soil [6]. Soil colloids exhibit a strong affinity for divalent Ca\({}^{2+}\), rendering them more stable than monovalent Na\({}^{+}\)[7]. The displaced Na\({}^{+}\) is subsequently leached away with irrigation water. However, gypsum has a low solubility, and in the absence of irrigation or rainfall, there is a risk of insufficient hydraulic conductivity. The combined application of straw organic matter can mitigate this issue. The macromolecular organic acids generated during straw decomposition readily bind with Ca\({}^{2+}\) ions, facilitating the dissolution of gypsum [8]. Additionally, returning straw to the soil releases a substantial amount of nutrients. [PERSON] et al. [9] observed that long-term straw return increased the soil organic carbon and total nitrogen by 8.85% to 15.01%, effectively enhancing soil fertility. The application of straw can also modify the soil carbon-to-nitrogen ratio and promote nutrient cycling, thereby benefiting crop growth [10; 11]. Soda saline-alkali soil typically leads to the fixation of essential nutrients, such as phosphorus and calcium, under conditions of high salinity and alkalinity [12]. Additionally, it hinders the absorption of nutrients, thereby inhibiting plant growth [13]. Soil salinization also negatively impacts the accumulation of organic matter and the soil carbon cycle, which are key processes for maintaining soil health [14].