title: soil
design: First, effective sequences of all samples need to be obtained according to barcode. Then the quality of reads was controlled and filtered. Then, according to overlap relation between PE reads, the paired reads are merged into a sequence. Finally, the high-quality sequence of each sample was obtained by splitting the barcode and primer sequences, and the sequence direction was corrected and the chimera was removed according to the positive and negative barcode and primer directions during the process