From soil health to tea flavour: Organic fertilisation enhances microbial communities and aroma compounds

The excessive use of synthetic fertilisers in tea plantations has led to soil acidification, degradation, and environmental concerns, raising the need for sustainable alternatives. This study investigated the effects of organic fertiliser application on soil microbial communities, tea aroma, and yield through a 7-year field trial with four treatments: control (CK), pure chemical fertiliser (NPK), chicken manure (CM), and rapeseed cake (RC). Results showed that organic fertiliser treatments (CM and RC) significantly improved soil physicochemical properties, including pH, soil organic carbon (SOC), and available nitrogen (including mineral nitrogen and labile organic nitrogen) while alleviating soil acidification caused by NPK treatment. Organic fertilisers also enhanced microbial diversity and altered the composition of bacterial and fungal communities, with RC treatment showed the most distinct microbial profiles. Tea aroma indices, particularly geraniol and linalool, were significantly improved under RC treatment, correlating with changes in soil properties and microbial communities. Moreover, our study reflected that tea aroma can be indirectly influenced, and variations in the bacterial community appear to have a more pronounced effect on these changes in aroma. These findings suggested that organic fertilisers, especially rapeseed cake, can improve tea aroma and soil health, providing a sustainable alternative to synthetic fertilisers in tea plantations.