Effects of long-term intercropping of pecan (Carya illinoinensis) on
bacterial community in tea rhizosphere soil and tea quality
Abstract
Using the 16S rDNA high-throughput sequencing, the effects of a nested
pecan in a typical tea garden on soil bacterial group species
composition and marker species were comparatively analyzed to determine
whether the nested pecan contributed to an increased soil microbial
diversity in the tea plant rhizosphere. We explored the effects of the
underlying mechanisms of this complex ecosystem on tea quality by
determining soil physicochemical properties and tea quality under two
types of planting modes, intercropping of pecan versus pure forest. Our
observations indicated that Allorhizobium, Neorhizobium, Pararhizobium,
Rhizobium, and Enterobacter, with pollution-degrading effects, were
enriched in the soil bacterial communities of interplanting pecan in the
tea garden model. There was a significant enrichment of prebiotic
functional bacteria, such as Pedosphaeraceae and the
Coriobateriaceae_UCG-002 genus, which has growth stimulation and
disease resistance, while Chloroflexi and Firmicutes, which dominate
denitrification in the soil, were inhibited. The soil microbial
co-occurrence network increased in complexity and decreased in mutual
exclusivity, and the complex interactions among bacterial populations
tended to be stable. The phenol ammonia ratio in tea leaf pieces was
lower and the comprehensive quality evaluation of tea was improved in
the intercropping model. We conclude that the soil microbial community
composition under this complex model may not only promote material
cycling in microecosystems but also effectively reduce the transmission
risk of soil-borne diseases. The tea rhizosphere soil microbial
community structure could be rebalanced and shifted toward a more
favorable tea quality formation through the introduction of pecan into
the tea plantations.