Remediation of deterioration in microbial structure in continuous Pinellia ternata cropping soil by crop rotation.

Pinellia ternata is a traditional Chinese herb that suffers from continuous cropping (CC), which significantly decreases both yield and quality. The influence of CC on the microbiome in P. ternata rhizosphere and the effects of remediation on microbiota by rotational cropping (CR) were assessed by Illumina high-throughput sequencing technology. CC tends to decrease the α-diversities as a function of cultivation time, whereas CR tends to increase them. Differentially abundant analysis showed that microbial structure was important in maintaining the health status of P. ternata rhizosphere. Results suggested that CC soils were mainly enriched for Pseudomonas, Rhizobium, and Streptophyta operational taxonomic units (OTUs), while the CR soils were mainly enriched for Rhizobium, Pseudomonas, Flavobacterium, Sphingomonas, Rhizobacter, and Arthrobacter OTUs. On the basis of the community dissimilarities, we grouped all sample replicates into three post hoc clusters in which soils were defined as healthy, health-suppressed, and health-depressed soils. The three soil types represented different soil physicochemical properties. The activities of the microbiome features, including ammonia oxidizer, sulfate reducer, nitrite reducer, dehalogenation, xylan degrader, sulfide oxidizer, nitrogen fixation, atrazine metabolism, chitin degradation, degraded aromatic hydrocarbons, and chlorophenol degradation, were also considerably different among the three soils.