Changes in Rhizosphere and Bulk Soil Microbial Communities of Tableland Tea Garden and Ancient Tea Plantation in Southwest China

Abstract

Tea (Camellia sinensis L.), an important economic crop in China, is highly favored by the population. Microorganisms can help plants acquire soil nutrients and cope with various stresses, and the diversity and structural composition of the rhizosphere microbial community of tea plants are crucial for ensuring the growth and quality of tea leaves. Therefore, we studied the differences in soil nutrients, enzyme activities and microbial communities between two different tea gardens (a tableland tea garden and an ancient tea plantation) in different ecological niches (rhizosphere and bulk soil), as well as the impacts they experienced. The results show that the soil pH levels in the ancient tea plantation were within the optimal range (4.5–5.5), and both rhizosphere and bulk soil nutrients in the ancient tea plantation were higher than those in the tableland tea garden, except for TP; the nutrients in the rhizospheres of ancient tea trees were more abundant. Moreover, higher enzyme activities were observed in the rhizosphere soil than those in the bulk soil in both tea gardens, and both the tableland and ancient tea garden soils were subjected to a certain degree of C&N limitations. The microbial communities of the two tea gardens were dominated by bacteria, but the α-diversity of the bacterial and fungal communities in the rhizosphere soil of the tableland tea garden was higher than that in the ancient tea plantation. The bacterial communities were largely dominated by Proteobacteria and Acidobacteriota, and the fungal communities were largely dominated by Ascomycota and Basidiomycota in the two tea gardens. The structure and composition of soil bacterial communities in the two tea gardens were similar, whereas significant differences were observed in the fungal communities. In addition, soil pH and SWC were the key factors influencing the fungal community in both the rhizosphere and bulk soil in the two tea gardens, whereas the bacterial community was more significantly affected by soil TN, NH4+-N, SWC and DON. These findings provide essential foundational information for the preservation of ancient tea plantations, the ecological adaptability of ancient tea trees and the management of tableland tea gardens.