Impact of N application rate on tea (Camellia sinensis) growth and soil bacterial and fungi communities

Purpose Applying excessive N is a common strategy in tea plantations. Fungal and bacterial responses to N fertiliser addition in tea plantations, especially their relationship with tea growth, quality, and soil microbiome composition, remain unclear. Methods We performed a field experiment using different N fertiliser application rates for 5 years (2016‒2020) in a tea-producing region of China. Results The N application rate of 360 kg ha −1 y −1 achieved the highest tea yield and quality. Bacterial diversity and community responses to N addition were more apparent than fungal diversity and community responses. Partial least square path modelling suggested that N addition directly affected the diversity and communities of bacteria and fungi and indirectly affected bacterial community and fungal diversity by altering soil contents. N fertiliser application contributed to tea growth but did not maintain high microbial diversity. Conclusion Fungal alpha and beta diversity had a greater effect on tea yield and quality than bacterial diversity; therefore, more attention should be given to fungi such as ligninolytic and cellulolytic taxa, which play a stable role in nutrient cycling and organic matter decomposition in tea plantations, favouring tea growth in the long term.