Abstract: BackgroundThe sandy soils in western Jilin Province exhibit poor structure, low organic carbon content, and are prone to wind and water erosion, leading to low crop yields, which severely constrains sustainable agricultural development in the region. This study explores effective pathways for rapidly improving soil fertility, enhancing erosion resistance, and increasing crop productivity in these sandy soils through the application of mixed organic materials.MethodsUsing sorghum as the test crop, a field experiment was conducted with seven treatments: no organic amendment (CK), sorghum straw return (G), straw combined with sheep manure (GF), sheep manure alone (F), straw combined with microbial agent (GS), microbial agent alone (S), and manure combined with microbial agent (FS). The study investigated the effects of these different organic material combinations on soil aggregates, active organic carbon fractions, and crop yield.ResultsThe application of organic materials significantly improved soil structure. The GF treatment yielded the best results, increasing the content of water-stable macroaggregates (>0.25 mm) and the mean weight diameter (MWD) by 12.11% and 55.6%, respectively. Soil organic carbon (SOC) and its active fractions were significantly enhanced. The GF treatment led to the greatest increases in SOC, particulate organic carbon (POC), and easily oxidizable organic carbon (EOC), while the GS treatment resulted in the highest dissolved organic carbon (DOC) content. Principal component analysis identified DOC as the core factor influencing changes in carbon fractions, and a significant correlation (P<0.05) was found between POC and aggregate stability. Regarding crop yield, the GF treatment significantly increased sorghum yield by 77.3% compared to CK, highlighting the synergistic effect of combining straw and manure. ConclusionsThe combined application of straw and sheep manure (GF) facilitates a synergistic mechanism whereby "straw's slow-release carbon builds the framework, and manure's fast-release carbon provides cementation." This effectively promotes the formation of macroaggregates, enhances organic carbon sequestration, improves soil resistance to wind and water erosion, and achieves high crop yields. The study provides a scientific basis for the rapid improvement of sandy soils and soil-water conservation in the region.