Soil carbon maintained by perennial grasslands but lost in field crop systems over 30 years in a temperate Mollisol according to longitudinal, compaction-corrected, full-soil profile analysis

To mitigate climate change, some seek to store carbon from the atmosphere in agricultural soils. However, our understanding of how agriculture affects soil organic carbon (SOC) is muddied by studies 1) lacking longitudinal data, 2) ignoring bulk density changes, or 3) sampling only surface soils. To better understand SOC trends, here we measured changes over 30 years in density-corrected, full-soil-depth (90 cm) SOC stocks under 6 cropping systems and a restored prairie in a Mollisol of southern Wisconsin, USA. Cash-grain systems and alfalfa-based systems lost SOC. Prairie and rotationally-grazed pasture maintained SOC. Average SOC losses for cash-grain and alfalfa-based systems were -0.82 (±0.12) and -0.64 (±0.17) Mg C ha-1 yr-1, respectively. Sensitivity analysis showed that incomplete methodologies overestimated SOC improvements. Our findings using more comprehensive methods demonstrate the inadequacy of row-crop systems and the need for well-managed grasslands to protect SOC in prod..., , , # Soil carbon maintained by perennial grasslands but lost in field crop systems over 30 years in a temperate Mollisol according to longitudinal, compaction-corrected, full-soil profile analysis

[https://doi.org/10.5061/dryad.b8gtht7mv](https://doi.org/10.5061/dryad.b8gtht7mv)

This dataset contains percent carbon, percent nitrogen, and soil bulk density data for samples from the Wisconsin Integrated Cropping Systems Trial (WICST) collected in 1989, 2009, and 2019. WICST compares six cropping systems and a restored native grassland common to the Upper Midwest United States of America in a randomized complete block design. This data was collected to measure changes in soil organic carbon stocks over time as a result of different cropping systems and land use.

## Description of the data and file structure

This data is available as an Excel spreadsheet and associated Microsoft Word document. In these, there is a full description of the experiment and data.

## Code/Software

SAS code use...