Soil structure changes under reduced tillage and cover cropping enhance carbon mineralization in Mediterranean croplands

This dataset contains soil physical, chemical, and biological measurements
from a long-term conservation agriculture experiment at the Conservation
Agriculture Systems Innovation (CASI) site in Five Points, California.
Data were collected from undisturbed soil cores sampled in October 2019,
after 19 years of differential management comparing conservation tillage
with cover crops (CTCC) versus standard tillage without cover crops
(STNC). The dataset includes: (1) soil water retention curves measured
using the HYPROP evaporation method; (2) time-series CO2 efflux
measurements across a controlled moisture gradient from saturation to
approximately -80 kPa; (3) total carbon and nitrogen content determined by
elemental combustion; (4) bulk density and porosity measurements; and (5)
fitted van Genuchten-PDI model parameters for each soil core. These data
support the finding that conservation management significantly increases
soil carbon stocks while simultaneously enhancing carbon-specific
respiration rates under wet conditions, with implications for carbon
sequestration in irrigated agricultural systems.