Increased Soil Fertility in Tea Gardens Leads to Declines in Fungal Diversity and Complexity in Subsoils

Abstract

Soil fungi are key drivers regulating processes between ecosystem fertility and plant growth; however, the responses of soil fungi community composition and diversity in deeper soil layers to the plantation and fertilization remain limited. Using soil samples along with vertical soil profile gradients with 0–10 cm, 0–20 cm, 20–40 cm, and 40–60 cm in a tea garden, we used Illumina sequencing to investigate the fungal diversity and assemblage complexity, and correlated to the low, middle, and high-level fertilize levels. The results showed that the fungal community dissimilarities were different between adjacent forests and tea gardens, with predominate groups changed from saprotrophs to symbiotrophs and pathotrophs after the forest converted to the tea garden. Additionally, the symbiotrophs were more sensitive to soil fertility than pathotrophs and saprotrophs. Subsoil fungal communities present lower diversity and fewer network connections under high soil fertility, which contrasted with the trends of topsoil fungi. Soil pH and nutrients were correlated with fungal diversity in the topsoils, while soil K and P concentrations showed significant effects in the subsoil. Overall, the soil fungal communities in tea gardens responded to soil fertility varied with soil vertical spatial locations, which can be explained by the vertical distribution of fungal species. It was revealed that fertility treatment could affect fungal diversity, and alter network structure and potential ecosystem function in tea garden subsoils.