Soil samples were collected from 0-30 cm. DNA was extracted from the soil. Soil DNA was amplified using nosZ and amoA primers with adaptors to target denitrifying bacteria, and ammonia oxidizing bacteria and archaea, respectively. Soil DNA was also amplified using nifH and nodZ primers to target nitrogen fixation and soybean specific Bradyrhizobium.  A second PCR reaction was used to insert a unique barcode to this sample