Abstract: Soil acidification reduces productivity. To explore the changes of soil pH in Guangxi between 1984 and 2019, geostatistics, dynamic degree and distribution index were used to analyze the sampling point data of the project and the long-term observation data from 2010 to 2019. The results showed that soil pH decreased from 1984 to 2019, and its distribution changed from uneven to relatively continuous. The area proportion of soil pH grade was as follows: grade 2 > grade 3 > grade 4 > grade 1 > grade 5 > grade 6. The soil pH was mainly composed of grade 2 and grade 3. The area of grade 2 and grade 3 accounted for 76.71% of total area in 1984 and 84.84% in 2019. In terms of change rate, grade 1 (-1.99%) and grade 5 (0.44%) showed the most rapid change. The dynamic degree was following an order of grade 1 > grade 6 > grade 5 > grade 2 > grade 3 > grade 4. The pH distribution index curve of grade 6 fluctuated significantly across different elevation regions.

Key words: soil pH, space-time evolution, geostatistics, Guangxi