In natural drylands, the formation of pedogenic carbonate, or secondary calcite (CaCO3), is critical in shaping soil hydrologic and biogeochemical properties and modifying the global carbon cycle over geological time. When dryland ecosystems are converted to managed agricultural sites, irrigation water can supply HCO3- and Ca2+, accelerating rates of CaCO3 formation and releasing abiotic CO2. These data were collected to investigate the abiotic and biotic processes that produce soil CO2 in dryland soils at an irrigated pecan orchard in Tornillo, Texas. Measurements were made at two sites within the orchard, Pecan_Coarse and Pecan_Fine, which have contrasting soil textures and associated differences in soil salinity, pedogenic carbonate accumulation rates, and tree size.

The dataset includes high temporal resolution, 5-minute measurements of soil CO2, soil O2, soil moisture, and soil temperature at two depths, 30 cm and 60 cm below the ground surface, along with surface soil CO2 efflux measured using Eosense eosFD chambers. Sensors were logged using six total logging devices, including separate eosFD loggers, Teros loggers, and Campbell CR1000 systems. Raw logger files were processed to convert voltages and sensor signals to physical units, apply calibration constants, and merge variables into continuous 5-minute time series. Quality control was conducted by hand using a custom R package, with suspect observations flagged when they were associated with issues such as pre-deployment values, sensor power loss, or sensor failure. Both QC-flagged files and cleaned files, in which flagged observations are replaced with NA, are included.

The overall objective of the dataset is to support quantification of abiotic CO2 release during the precipitation of irrigation-induced calcite, as a function of spatial variability caused by soil texture and temporal variability associated with growing season dynamics and irrigation events. The data were collected as part of the Dryland Critical Zone project (NSF Award #2012475) and a Low-temperature Geochemistry and Geobiology project (NSF Award #1853680). Related soil chemistry and texture data for these two profiles were published by Ortiz and Jin (2021) in Geoderma.