Reliance on synthetic fertilizers poses serious challenges to sustainable vegetable production in arid regions, where sandy loam soils have low organic matter, nitrogen content, and microbial activity, resulting in weak nutrient cycling. This study evaluated an integrated soil fertility management combining cowdung manure, wheat straw, and cellulose decomposing bacteria to improve soil fertility and cabbage performance over two consecutive growing seasons. A split-split plot experimental design was used to test different application rates of the treatments including a mineral fertilizer control, and bacterial inoculum. Integrated organic and biological amendments increased soil organic matter, total nitrogen, and the availability of phosphorus, potassium, magnesium, and sulfur. Soil microbial populations increased nearly threefold, with the highest values recorded under combined applications of organic and biological amendments. Cabbage quality improved through higher vitamin C content, protein concentration, total soluble solids, and titratable acidity, alongside reduced nitrate accumulation compared with mineral fertilizer application. These results indicate that biologically enhanced organic amendments offer a sustainable alternative to synthetic fertilizers by improving soil health, nutrient availability, and cabbage quality under arid conditions. Future studies should assess long-term soil biological stability across other high-value vegetable crops to support sustainable intensification in arid regions.