Effect of biochar on soil acidity and aluminum morphology in tea plantations

Abstract

Soil acidification in tea plantations has become a key factor restricting the development of the tea industry. Biochar reduces soil acidity significantly and has good short-term effects of acidic soil improvement in tea plantation trials, but the duration of the effect and the long-term environmental effects of biochar are still unclear. In this study, the acidic tea plantation soil to which biochar was applied five years ago was studied. The biochar applied to the soil was separated and analyzed for surface elements, and the aluminum form of the soil was measured. The results showed that : (1) Five years after biochar was applied to the soil, the surface aluminum elements of biochar increased significantly, indicating that biochar had a certain degree of adsorption effect on aluminum in the soil; (2) the pH of tea plantation soil increased significantly; (3) the exchangeable aluminum [Al3+] and monohydroxy and dihydroxy aluminum [Al(OH)2+, Al(OH)2+] both had the potential to convert to colloidal aluminum [Al(OH)3], and this conversion reduced the content of reactive aluminum in the soil, thus increasing the soil pH and reducing the toxicity of aluminum to plants.