Abstract: Acidification is a common phenomenon of tea garden soils. In order to understand the long-term effects of acidification on mineral components and potassium in tea garden soils, the red soil developed from granite was selected, and the forest land of the same soil type was used as the control. Through soil analysis and simulation experiments, the changes and differences of soil minerals and soil potassium forms caused by soil acidification were compared after 20 and 50 years of continuous planting of tea trees. The results show that the acidification of tea garden soils reduced the capacity of slow available potassium and potassium containing minerals such as mica and feldspar in sand and silt fractions, promoted the transformation from 2∶1 type (Illite) minerals to 1∶1 type minerals (Kaolinite) in clay fraction, and reduced the total potassium content of the soils. With the increase of soil acidity, the proportion of mineral bound form and non-exchangeable form K in the soils decreased gradually. While the proportion of water-soluble K increased gradually. After soil acidification, the potassium applied to the soils mainly existed in water-soluble and exchangeable forms with high activity. The proportion of K in non-exchangeable form was significantly reduced, and the buffering ability of soil to external source K was gradually reduced. The application of zeolite in acidic soils could enhance the buffering ability of the soils to potassium transformation and reduce the leaching loss risk of soil potassium. The results show that soil acidification in tea gardens could significantly reduce soil potassium, weaken soil potassium supply capacity and potassium buffering ability.

Key words: tea garden, acidification, potassium minerals, potassium supply capacity, potassium form, buffering