| To address the issues of poor soil structure, low fertility, and low crop productivity in medium-low yield fields on the Loess Plateau, this study conducted field experiments to investigate the effects of different improvement measures on soil structure, nutrient content, and crop yields of maize and soybeans. The aim was to identify suitable soil improvement solutions and provide scientific basis for enhancing soil fertility and ensuring stable yield increases in dryland agriculture. Six treatments were designed: traditional fertilization (CK), γ-polyglutamic acid water-retaining agent (P), soil loosening agent (S), 30% organic fertilizer substitution (F), 30% organic fertilizer substitution + γ-PGA (FP), and 30% organic fertilizer substitution + soil loosening agent (FS). These treatments were used to study their impacts on soil bulk density, compactness, aggregate stability, organic matter, total nitrogen, available phosphorus, available potassium, and crop yields. Results showed that all improvement measures significantly reduced soil compactness by 19.33%–28.19% and increased corn yield by 12.07%–30.73%. Compared with CK, the FS treatment reduced soil bulk density by 7.01%, increased soil aggregate stability (mean weight diameter by 18.26%; geometric mean diameter by 21.96%), and demonstrated the most significant improvements in soil organic matter, total nitrogen, available phosphorus, corn grains per ear, and 100-grain weight. The FP treatment achieved the highest available phosphorus content (149.95 mg/kg). While soybean grain yield and 100-grain weight showed slight increases under all improvement measures, no statistically significant differences were observed compared to CK. In conclusion, the 30% organic fertilizer substitution combined with soil loosening agent (FS treatment) proved most effective in improving soil structure, enhancing soil fertility, and increasing crop yields. This method is therefore recommended as an effective measure for improving soil quality and crop productivity in medium-low yield dryland areas of the Loess Plateau. |