Long-Term effects of different land use systems on soil aggregate stability and organic matter

Soil aggregate stability (AS) and organic matter (OM) are key indicators of soil physical quality and ecosystem functioning, yet their long-term responses to contrasting land use systems under varying management intensities remain insufficiently quantified. This study evaluated the effects of long-term land use on AS and OM under natural ecosystem–forest land (NEFL), horticultural land (HL), and arable land (AL). Soil samples were collected from multiple representative sites within each land use type, and differences in AS and OM were statistically assessed to elucidate land use–induced structural changes. The results showed that land use type significantly influenced both AS and OM. Soils under NEFL consistently exhibited the highest AS and OM values, reflecting the stabilizing effects of continuous vegetation cover and minimal soil disturbance. Compared to NEFL, AS and OM decreased markedly by 31.6% and 42.9% in HL and by 54.4% and 67.0% in AL, respectively, indicating a progressive decline in soil structural quality with increasing land use intensity. Horticultural lands displayed intermediate values, suggesting a partial preservation of soil structure under perennial systems, whereas arable lands showed the lowest AS and OM values, consistent with the cumulative effects of frequent soil disturbance, reduced residue retention, and accelerated organic matter mineralization. Overall, the findings demonstrate that long-term soil structural stability is governed not only by land use type but also by management intensity and organic matter input pathways. Strategies that promote residue retention and minimize disturbance are essential to sustain soil structure and prevent physical degradation in agricultural systems.