Overview and trends of international research on soil acidification in tea plantations

The acidification of tea garden soils has emerged as a global concern, posing a significant challenge to the sustainable development of the tea industry. To comprehensively trace the evolution of research on this topic and grasp its core areas and frontier trends, this paper conducts an analysis of 118 relevant publications retrieved from the Web of Science (WoS) core collection database spanning the years 2000 to 2023. The results indicate that since 2018, there has been a notable surge in international research on soil acidification in tea gardens. China leads the way with the highest number of publications and the greatest influence, with all five top research teams globally in terms of publication output in this field originating from China. The focus of research in this domain primarily revolves around the multifaceted impacts of soil acidification on tea garden ecosystems, encompassing alterations in soil physicochemical properties, disruptions to carbon, nitrogen, and phosphorus cycling, modifications to soil microbial ecosystems, and consequences for tea yield and quality. Additionally, studies delve into soil aluminum toxicity, tea plant aluminum tolerance mechanisms, and strategies for ameliorating soil acidification in tea gardens. Specifically, soil acidification undermines the stability of soil aggregates, diminishing buffering capacity and exacerbating soil compaction, thereby reducing soil water-holding capacity and hindering root growth. This, in turn, leads to substantial leaching of base cations, decreasing base saturation and nutrient availability, fostering the mobilization and dissolution of aluminum, and elevating the risk of heavy metal (e.g. Cd, Pb, Cr) accumulation in tea leaves. Moreover, soil acidification accelerates the loss of soil carbon, nitrogen, and phosphorus, reduces soil microbial diversity, inhibits the growth of certain beneficial microorganisms (such as Pseudomonas adaceae and Bradyrhizobium), and impairs microbial activity, thereby adversely affecting the normal growth and development of tea plants, as well as the yield and quality of tea leaves. Therefore, it is necessary to implement targeted measures to prevent and control soil acidification in tea gardens, depending on the varying degrees of acidity. For instance, the application of organic fertilizers and biochar can effectively alleviate soil acidity and enhance soil fertility. Furthermore, the biogeochemical cycle of aluminum serves as a focal point of research in this field, while the persistent influence of soil acidification on the nitrogen and phosphorus cycles in tea plantation systems remains a heated and cutting-edge topic. In summary, this study provides a comprehensive and insightful overview of the current state of international research on tea garden soil acidification, along with its advancements. By meticulously synthesizing pivotal findings and pinpointing emerging trends, it imparts invaluable perspectives tailored for researchers, policymakers, and practitioners alike, thereby catalyzing the formulation of effective soil amelioration strategies and fostering the sustainable growth of the global tea industry.