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.

Automated summary

This study demonstrates that moderate nitrogen fertiliser application is an effective strategy to increase tea yield and quality in tea plantations. Bacterial diversity and community responses to nitrogen addition are more pronounced than fungal diversity and community responses. Nitrogen addition directly affects the diversity and communities of bacteria and fungi, and indirectly affects bacterial community and fungal diversity by altering soil contents.