Potassium (K) deficiency is widespread in Alfisols on which tea is grown, and quantifying the availability of K to the tea plants is important in designing fertilizer regimes and in ensuring that tea production systems remain sustainable. In this study, the contents of available K, its release characteristics, and the composition of K-bearing minerals were determined for Alfisols on which tea had been grown for 5, 10, 15, or 30 years. The contents of exchangeable K (EK), non-exchangeable K (NEK), K extracted with sodium tetraphenylboron, release threshold values of total labile K, and equilibrium K concentration increased as the age of the plantation increased. However, the content of EK even in the oldest plantations was far below the critical value for K deficiency (80 mg kg⁻¹). The concentration of total labile K was higher than that of EK irrespective of the age of the plantation, which points to serious exhaustion of NEK reserves. Furthermore, compared to older plantations, the younger plantations contained less of illite and chlorite and more of kaolinite and vermiculite in the clay fraction of the soils. Chlorite and illite was significantly positive correlated to available K either in the surface layer (0–15 cm) or in the deeper layer (15–30 cm), whereas kaolinite was significantly and negatively correlated to available K at both depths. Although tea plantations increased the reserves of soil available K, the increase was not enough either to overcome the deficiency of available K—which continues to be extremely severe—or to prevent the distortion of clay minerals in Alfisols. Adequate inputs of K are therefore essential for increasing the inherent capacity of the Alfisols to supply K and, in turn, to obtain high yields and superior-quality tea.

钾（K）缺乏症普遍存在于生长茶的Alfisols中，并且量化钾对茶树的可用性对设计肥料制度和确保茶生产系统保持可持续性很重要。在这项研究中，确定了茶已生长5年，10年，15年或30年的Alfisol的有效K含量，其释放特性和含K矿物的组成。可交换钾（EK），不可交换钾（NEK），用四苯硼钠提取的钾的含量，总不稳定钾的释放阈值和平衡钾的浓度随着种植年龄的增加而增加。但是，即使在最古老的人工林中，EK的含量也远远低于缺钾的临界值（80 mg kg ^-1）。无论人工林的年龄如何，总不稳定K的浓度都高于EK的浓度，这表明NEK储备严重枯竭。此外，与较老的人工林相比，较年轻的人工林在土壤的黏土中所含的伊利石和绿泥石更少，而高岭石和ver石的含量更高。在表层（0–15 cm）或较深层（15–30 cm）中，亚氯酸盐和伊利石与有效钾呈显着正相关，而在两个深度上，高岭石与有效钾呈显着负相关。尽管茶园增加了土壤速效钾的储量，但增加量不足以克服速效钾的不足（后者仍然极为严重），也不足以防止铝镁土中粘土矿物的变形。