| RecType | | Physical quantity | Record type |
| RecYear | | Physical quantity | Year of record |
| RecMonth | | Physical quantity | Month of record |
| RecDay | | Physical quantity | Day of record |
| doy | | Physical quantity | Day of year |
| Plot_2017 | | Nominal | Plot designation in 2017, after irrigation lines were shifted |
| gwc | | Physical quantity | gravimetric water content on soil sample used to measure extractable C and microbial biomass C. |
| ppm_micbio | | Physical quantity | Soil microbial biomass C (ppm) (0-10 cm depth) measured on a TOC analyzer using chloroform fumigation extraction |
| init_soilppm | | Physical quantity | Soil extractable organic C (ppm) (0-10 cm depth) from unfumigated soil samples measured on a TOC analyzer |
| Current | | Nominal | Treatment in 2017, after irrigation lines were shifted. |
| Replicate | | Nominal | Irrigation line: (A) started in 1991, (B) started in 1993. |
| Transect_1993 | | Nominal | Previous treatment (1991-2016). |
| Plot_1993 | | Nominal | Plot designation 1991-2017, before irrigation lines were shifted. Plots that are currently in the reduced (R) treatment did not have plot numbers during this time
|
| Plot_1992 | | Nominal | Plot designations in 1992, while second irrigation line was being added. These plot designations are not typically used.
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