Evaluation of soil enzyme activities and microbial communities in tomato continuous cropping soil treated with jerusalem artichoke residues

Jerusalem artichoke (JY) (Helianthus tuberosus L.) has been reported to have a strong inhibitory effect on weed growth and root knot nematodes, but little information is available on the effects on soil ecosystems, especially soil microorganisms and soil enzyme activities. Understanding the dynamics of soil microbes and soil enzyme activities in cropping systems can help determine how agricultural practices influence soil processes mediated by JY residues. This study used a pot experiment, with five-year continuous cropping soil of tomato plants as the experimental material and 2% (w/w) JY residue as the treatment material in the soil. The treatment was compared to continuously monocropped tomato soil that was not treated with JY residues. The results of 16S high-throughput sequencing showed that both fungal and bacterial community structure and composition varied significantly at each stage of JY treatment. The analysis showed that the major phyla in the soil fungal community included Ascomycota, Zygomycota and Basidiomycota. Chytridiomycota was dominant in only the JY-treated soil. At the genus level, the abundances of Mortierella, Cephaliophora, Cryptococcus and Fusarium notably changed at each stage of JY treatment. In the bacterial community in the JY-treated group, the abundance of Proteobacteria increased significantly, while that of Firmicutes decreased significantly, compared to the control group. JY enhanced the activity of soil sucrase and urease. In addition, the soil sucrase activity showed a strong negative correlation with Fusarium and Bacillus. Overall, our results revealed that JY residues changed both the soil bacterial and fungal community composition and the soil enzyme activities.