Long-term tea cultivation degrades soil health: Insights from microbial structure and function in tea gardens

Abstract

Tea (Camellia sinensis L.) is a globally cultivated beverage crop, but long-term cultivation may degrade soil health by altering biological properties. We used high-throughput sequencing, phospholipid fatty acid (PLFA) analysis, and the Quantitative Microbial Ecology Chip (QMEC) to compare soil microbial structure and function in tea gardens and adjacent natural forests. Soil pH was significantly lower in tea gardens across all depths compared to natural forests. PLFA analysis showed reduced Gram-positive and Gram-negative bacterial, fungal, and total microbial biomass in tea gardens. High-throughput sequencing revealed distinct bacterial and fungal communities, with tea gardens exhibiting lower alpha-diversity than natural forests. Unique bacterial operational taxonomic units (OTUs) in tea gardens were negatively correlated with key functional genes (e.g., carbon and nitrogen cycling), whereas natural forest OTUs showed positive correlations. Soil pH decline, driven by long-term tea cultivation, was the primary factor shaping these microbial shifts. These findings indicate that extended tea planting impairs soil functions, compromising soil health. The observed deterioration underscores the need for targeted management to address the interplay between land use, soil health, and microbial dynamics, highlighting avenues for future research to enhance soil resilience in tea gardens.

Graphical abstract

Keywords

soil health / carbon and nitrogen cycling / tea planting / soil microbiome / tea plantation

Highlight

	● Long-term tea planting practices caused strong soil acidification across all soil layers.
	● All tea gardens showed much lower Gram-positive and -negative bacteria, fungi, and total microbial biomass relative to natural forests.
	● The relative abundance of bacteria related carbon and nitrogen cycling functions predicted by FAPROTAX was much lower in all tea plantations compared with natural forest.
	● Soil acidification was the main reason in affecting microbial community and functions by selecting a large number of microbial tax and causing remarkable decline in alpha-diversity.

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