Microbial Biomass, Community Diversity, and Enzyme Activities in Response to Urea Application in Tea Orchard Soils

To improve yield and quality in tea orchards, a large amount of nitrogen (N) fertilizer is usually applied. Our objective was to evaluate the effect of N application on microbial community and activity in tea orchard soils and assess the relative importance of fertilizer application versus land use in structuring the soil microbial community. Urea application caused significant decreases in soil microbial biomass and enzyme activities in the three tea orchards. For the wasteland and forest, soil microbial biomass and enzyme activities significantly increased as a result of N fertilizer application. Urea application caused significant decreases in microbial functional and genetic diversity indices of the three tea orchards. Moreover, the bacterial and fungal phospholipid fatty acids were found to be changed with urea application. Multivariate analyses consistently showed that land use had a greater effect on soil microbial community diversity than urea application.