Soil Acidification and Its Temporal Changes in Tea Plantations of Guizhou Province, Southwest China

Abstract

Soil acidification is a significant problem in intensive agricultural systems, particularly in tea plantations. Guizhou province, located in the center of the karst mountainous region of southwest China, has the largest tea plantation area in China. However, the soil acidification characteristics in the tea plantations of Guizhou province, as well as their temporal changes, have not yet been adequately studied. Therefore, soil acidification and associated soil properties in the major tea‐planting counties of Guizhou province were extensively assessed, and the temporal changes in soil acidity over the past 11 years were also evaluated through long‐term and short‐term experiments. The results showed that the average soil pH in the tea plantations in Guizhou province varied from 4.08 to 4.87, with a mean of 4.47. The average cation exchange capacity (CEC), TEA (total exchangeable acidity, TEA), EH (exchangeable H+), and EA (exchangeable Al3+) values were 9.6, 3.7, 5.8, and 19.0 cmol/kg, respectively. Seasonal changes in tea plantation soil pH were observed in low‐ and moderately acidic soils but not in highly acidic soils. The soil pH values did not significantly change during three consecutive years of in situ observations but significantly decreased over the past 11 years at an average of 0.03 yearly. Correlation analysis revealed that the soil pH in tea plantations was significantly positively correlated with the content of specific amino acids, such as glutamic acid, arginine, and valine, but was significantly negatively correlated with certain soil physicochemical properties. The findings of this study indicate that soil acidification in tea plantations of the Guizhou province is severe and possesses distinctive attributes that should be considered for its effective management.