Optimizing irrigation and nitrogen (N) management in saline soils is critical for sustainable cotton production in arid regions that have been subjected to climate change. In this study, a two-year factorial field experiment (3 salinity levels × 3 N rates × 3 irrigation quotas) is integrated with the RZWQM2 model to (1) identify water–N–salinity thresholds for cotton yield and (2) to project climate change impacts under SSP2.4-5 and SSP5.8-5 scenarios (2031–2090) in Xinjiang, China, a global cotton production hub. The results demonstrated that a moderate salinity (6 dS/m) combined with a reduced irrigation (3600 m³/hm²) and N input (210 kg/hm²) achieved a near-maximum yield (6918 kg/hm²), saving 20% more water and 33% more fertilizer compared to conventional practices. The model exhibited a robust performance (NRMSE: 5.94–12.88% for soil–crop variables) and revealed that warming shortened the cotton growing season by 1.2–9.5 days per decade. However, elevated CO₂ (832 ppm by 2090) levels under SSP5.8-5 increased yields by 22.6–42.1%, offsetting heat-induced declines through enhanced water use efficiency (WUE↑27.5%) and biomass accumulation. Critically, high-salinity soils (9 dS/m) required 25% additional irrigation (4500 m³/hm²) and a full N input (315 kg/hm²) to maintain yield stability. These findings provide actionable strategies for farmers to optimize irrigation schedules and nitrogen application, balancing water conservation with yield stability in saline-affected arid agroecosystems that have been subjected to climate change.

The low water and fertiliser utilisation efficiency and soil quality degradation caused by high water and fertiliser inputs are the primary challenges facing goji berry cultivation in arid regions. A two-year field experiment was conducted from 2021 to 2022. The experiment included three irrigation rates (I₁, I₂, I₃) of 2160, 2565, and 2970 m³·hm⁻² and three nitrogen application rates (N₁, N₂, N₃) of 165, 225, and 285 kg·hm⁻² to quantify their impacts on soil nutrients, enzyme activity, and goji berry yield in the root zone. Results indicate that the indicators of soil nutrients decrease with increasing soil depth, with depths of 0–20 cm accounting for 24.80–72.48% of total content. With fertility period progression, soil organic matter at depths of 0–80 cm exhibits a “folded-line” trend, while total nitrogen, nitrate nitrogen, and available phosphorus show an “M”-type trend. At depths of 0–40 cm, the proportions of urease, sucrase, and alkaline phosphatase activities all exceeded 70%. At I₁ irrigation rate, enzyme activities gradually increased with rising nitrogen application rates. At I₂ and I₃ irrigation rates, enzyme activities first increased, then decreased with increasing nitrogen application. The highest yields of both fresh and dried fruits were achieved at I₂N₂ treatment, increasing by 14.17% and 14.78%, respectively, compared to conventional management (CK). Analysis of the random forest model indicates that the soil-driven factors influencing yield formation include SA, UA, APA, HPA, SOM, NH₄⁺-N, and TP. Analysis of SQI and yield fitted data indicates that water–nitrogen coupling significantly influences wolfberry yield by regulating soil quality. Partial least squares (PLS-PM) showed that N application and irrigation of soil nutrients did not cause a significant indirect impact on goji berry yield, but a significant positive effect on goji berry yield occurred through enzyme activity.

Freshwater scarcity in arid regions is driving increased use of saline irrigation, yet salinity severely degrades soil structure and suppresses enzymatic function. To address this critical challenge for sustainable soil management, this study systematically evaluated magnetized saline water (MSW) across three salinity levels (1, 3, and 6 g L⁻¹) and four magnetic field strengths (0, 0.2, 0.4, and 0.6 T), confirming the magnetic field intensity (C) × salinity (S) interaction. The comprehensive analysis integrated data on aggregate stability, key ion concentrations (Ca²⁺, Mg²⁺, Cl⁻), and major enzyme activities. Structural Equation Modeling (SEM) was utilized to quantify the underlying mechanisms, demonstrating that structural improvement is primarily driven by strong indirect pathways, mediated by optimized ion dynamics and increased enzyme-mediated organic matter turnover. The moderate-salinity (3 g L⁻¹), moderate-magnetic-field (0.4 T) regime emerged as the optimal balanced strategy for overall soil health. These findings offer a scalable approach, guiding future field-scale research toward long-term agricultural sustainability.

Saline water irrigation is increasingly used in arid regions, but its influence on soil aggregate stability remains uncertain when combined with magnetization pretreatment. A two-year field-pit experiment was conducted during 2024–2025 with four magnetization intensities (0, 0.2, 0.4, and 0.6 T) and three irrigation water salinity levels (≤1, 3, and 6 g L⁻¹). Mechanically stable and water-stable soil aggregates were analyzed in the 0–60 cm soil profile. Magnetization treatments changed aggregate-size distribution, but the dominant response differed between aggregate types. Mechanically stable aggregates mainly showed an increase in the >2 mm fraction and a decrease in the 0.053–0.25 mm fraction, whereas water-stable aggregates mainly showed an increase in the 0.25–1 mm fraction and a decrease in the 0.25 mm (R_0.25), mean weight diameter (MWD), and geometric mean diameter (GMD) varied with soil depth, salinity level, and year. Under S6, C4S6 increased the R_0.25 of mechanically stable aggregates in both years, reaching 73.90% in 2025 compared with 61.60% under C0S6. Correlation and exploratory path analyses suggested that changes in aggregate stability were mainly associated with the redistribution of key aggregate-size fractions. Under the field-pit conditions of this study, some magnetization treatments, particularly 0.4 T, were often associated with higher stability indices than non-magnetized saline irrigation, but this pattern was not consistent across all depths, salinity levels, years, and indicators. Long-term open-field validation is still required.

The cultivation of Salvia miltiorrhiza in arid regions is challenged by limited water availability and suboptimal soil aeration, which constrain nitrogen uptake and the accumulation of secondary metabolites. This study evaluated the integrated effects of magnetized and aerated irrigation on mitigating these constraints. Results indicated that the combined magnetized and aerated irrigation treatment demonstrated remarkable efficacy, achieving a 25.2% increase in soil nitrate nitrogen availability and 36.1% enhancement in root dry matter weight. Crucially, this optimized rhizosphere environment preferentially boosted the biosynthesis of salvianolic acid B and key tanshinones (T. IIA, Cryptotanshinone, T. I), with content increases exceeding 22% compared to conventional irrigation, representing substantial improvements in the herb’s therapeutic value. Water terminal magnetization proved superior to water source positioning, while aerated irrigation enhanced soil nitrification more effectively than magnetization alone. By concurrently improving rhizosphere oxygenation and creating favorable conditions for nutrient uptake, this strategy offers a sustainable approach for improving the quality and biomass of Salvia miltiorrhiza in water-limited environments.