design: Soil metagenomic DNA was extracted from each sample using the DNeasy PowerSoil Pro Kit. Bacterial 16S V3-V4 regions and fungal ITS regions were amplified using Illumina primer pairs with overhang adapters. Amplicon PCR was performed, amplified products were cleaned with AMPure XP Beads, and dual indices and Illumina sequencing adaptors were attached to the amplicons by a PCR reaction. 16S and ITS DNA amplicons were diluted and pooled for sequencing on an Illumina MiSeq platform (300 PE v3)