Towards Soil Health and Sustainable Development: Soil Physicochemical Response to Acid Rain Leaching

Abstract

Air pollutants (e.g., SO₂ and NO_x) were released as a result of the rapid socioeconomic growth and industrial development, leading to the formation of acid rain globally. Acid rain can be detrimental to soil systems because of their significant ecological functions, such as maintaining microbial activities and retaining nutrients for plants. This study investigated the impact of acid rain on soil physicochemical properties using simulated acid rain in laboratory-scale soil leaching experiments. Multiple sets of simulated acid rain with various pH levels were employed in the leaching processes. The properties of soil, including pH, electrical conductivity (EC), pH buffering capacity, and soil ions, were investigated after leaching with simulated acid rain. Results showed that the pH of simulated acid rain significantly influenced soil pH and the pH of soil leachate. There was a positive correlation between the pH levels of simulated acid rain and those of the soil. The surface soil (0–10 cm in depth) maintained a higher pH buffering capacity than the slightly deeper soil (10–40 cm in depth). Fourier transform infrared (FTIR) spectroscopic analysis indicated the consumption of inorganic carbonate functional groups, which could explain the loss of soil base cations.