Supplementing enhanced weathering with organic amendments accelerates the net climate benefit in rangeland soils

Carbon dioxide removal (CDR) technology that combines negative greenhouse gas emission pathways alongside substantial emissions reductions is needed to limit climate change. Rock dust amendments to soils is an emerging CDR technology that has the potential to decrease atmospheric CO2 via enhanced rock weathering (ERW), although there is considerable uncertainty regarding the efficacy of ERW with few multi-year field studies conducted to date. We explored combining finely-ground metabasaltic rock dust with other soil CDR technologies (compost, biochar) to stimulate carbon (C) sequestration and support plant growth. A combined amendment of  ground rock, compost and biochar observed the highest increases in soil C stocks (15.3 ± 6.1 Mg C ha-1) over three years. All treatments with compost applied alone or in combination increased soil C stocks by 2.0 ± 2.9 to 15.3 ± 6.1 Mg C ha-1.Ground rock only reduced rates of soil C decreases relative to the control, although still soil C stocks still ..., Site description
The field site was located at the University of California Sierra Foothill Research and Extension Center (SFREC) in Browns Valley, California. Soils are derived from Mesozoic and Franciscan volcanic rock and classified as xeric Inceptisols and Alfisols in the Auburn-Sobrante complex (Soil Survey Staff, 2020). Soil depth is approximately 30 cm overlaying unconsolidated rock. The area is classified as oak woodland and rangeland and has been exclusively grazed by cattle since at least 1960. Recent stocking rates were approximately 8 acres per cow. The field sites were not otherwise seeded, irrigated, fertilized, or tilled. The study region has a Mediterranean climate with average annual precipitation of 700 mm with high interannual variability and a mean annual temperature of 16.6 ºC (California Irrigation Management Information System, 2023), but experienced an extended drought throughout the experiment (Liu et al., 2022). The growing season occurs during the cool, wet we..., , # Supplementing enhanced weathering with organic amendments accelerates the net climate benefit in rangeland soils

## Description of the data and file structure

Treatments: 
Treatments included control (CT), ground rock (GR), compost (CP),
ground rock plus compost (GR + CP), and ground rock plus compost plus biochar (GR + CP + BC)

Sampling periods
Greenhouse gas sampling years: Year 1 = 2019-2020, Year 2 = 2020-2021, Year 3 = 2021-2022,
Soil carbon (organic TC and inorganic TIC), years: 2019, 2020, 2021, or 2022
Dissolved inorganic carbon (DIC), Dissolved organic carbon (DOC) and dissolved cations (calcium = Ca, Magnesium = Mg, and sodium (Na)), years: 2021-2022

Blocks
Block replicate of each treatment (B1, B2, or B3)

Depths
Soil sampled depth in cm (0-10, 10-20, 20-30, 30-40, or 40-50)

**Statistical values in all datasets:**

Mean = Mean, sd = standard deviation, se = standard error, ci = confidence interval

**The following subsets used to create figures are included in this da...