| Sample | | Nominal | Unique sample number |
| Year | | Physical quantity | Year of sample was collected |
| Month | | Nominal | Month of sample collection (NOV = November 2014, all other months 2015) |
| Plot | | Nominal | Field Plot IDs |
| Block | | Nominal | Field Block IDs |
| Nadd | | Nominal | N addition treatment: no = unfertilized control, yes = fertilized (10 g N as NH4NO3 per square meter per year in early May since 1986). |
| Burn | | Nominal | Fire treatment: yes = annually burned (in March or April) or no = unburned since 1986. |
| NaddBurn | | Nominal | Combination of fire (U = unburned or B = annually burned) and fertilization (C = unfertilized or N = fertilized) treatment. There are 4 combinations: UBC, UBN, BC, BN. |
| GWC | | Physical quantity | Gravimetric Water Content: field water content in grams water per gram soil after drying overnight at 105 degrees C. |
| DNA | | Physical quantity | DNA yield in micrograms DNA per gram dry soil; CTAB, P:C:IAA, PEG extraction method (DeAngelis et al. 2010, Environmental Microbiology 12, 3137-3149; Zeglin et al. 2016, Environmental Microbiology 18, 146-158). |
| 16SrRNAgeneCopy | | Physical quantity | copies of the bacterial 16S rRNA gene per g dry soil, using protocols in Fierer et al. 2005, AEM 71: 4117-4120 and Zeglin et al. 2016, Environmental Microbiology 18, 146-158. "." is missing data due to insufficient template DNA. |
| fungalITScopy | | Physical quantity | copies of the fungal ITS region per g dry soil, using protocols in Fierer et al. 2005, AEM 71: 4117-4120 and Zeglin et al. 2016, Environmental Microbiology 18, 146-158. "." is missing data due to insufficient template DNA. |
| 16S_bioproject_accession | | Physical quantity | Biosample accession number in NCBI SRA Bioproject PRJNA398249. |
| ITS_bioproject_accession | | Physical quantity | Biosample accession number in NCBI SRA Bioproject PRJNA509462. "." is missing data due to insufficient sequencing depth
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