Effects of transformation of Masson pine forest on characteristics of soil acidification and aggregate stability within polluted areas of Chongqing

Soil acidification is a formidable environmental issue which acts as a driver of change to alter forest tree species community composition over time. Forests characterized by the dominant tree species, Pinus massoniana, have shown extreme sensitivity to the increased soil acidity and are undergoing transformational shifts in community composition as a response. Planting treatments are a strategy often used to mitigate the harmful effects of increasing soil acidity, though little is known about how different treatments may affect soil physicochemical properties in P. massoniana forests. In this study, we characterized soil nutrient levels, stable soil aggregates, and soil acidification status of five different forest types(including pure stands of P. massoniana, Cinnamomum camphora, Schima superba and mixed stands of C. camphora-P. massoniana, S. superba-P. massoniana) to show how shifts in community composition may affect soil quality and help to inform management in areas impacted by acid rain. We collected and analyzed soil samples from O, A, and B horizons at 10 points within 20 m × 20 m plots replicated 3-4 times within each forest type. For O horizon soils, organic carbon and total nitrogen were lower in all forest types(P