The arable brown soil in Liaoning province is becoming more acidic over time. Researchers studied soil from different areas to understand how fast it acidifies and how well it can resist pH changes. They found that soil in the north and middle areas can resist pH changes better than soil in the south and east. The south area is acidifying the fastest, while the east area is slower. Factors like soil texture, cation exchange capacity, and organic matter affect how well soil can resist pH changes. Soil in the north and middle areas has higher pH buffer capacities due to their composition. Further research is needed to understand how fertilization and human activities affect soil pH.