Factors contributing to soil acidification in the past two decades in China

Soil acidification has become a major global issue, and it is important to study the causes and mechanisms of soil pH changes. This study detected soil pH changes in data collected from 1162 papers published during 1996–2000 and 2016–2020 in China, and it discussed the influencing factors on soil pH changes using Geodetector. The results showed that 58.4% of the collected data pairs were significantly acidified. Alfisols, desert soils, primarosols, semi-aqueous soils and aqueous soils were significantly acidified, while other types of soil did not change significantly. Soil pH on construction land decreased in units of 0.39 and on cultivated land decreased by 0.12, but soil pH changes in forest land and grassland were not significant. Nitrogen deposition, the amount of precipitation, sulphur deposition, temperature and vegetation planted in the soil had a great effect on soil acidification. This study provided a scientific reference for clarifying soil pH changes and made suggestions for subsequent soil remediation.