DOI: 10.5061/dryad.b8gtht7mv
title: Data from: Soil carbon maintained by perennial grasslands over 30 years but lost in field crop systems in a temperate Mollisol

description: To mitigate climate change, some seek to store carbon from the atmosphere
 in agricultural soils. However, our understanding about how agriculture
 affects soil organic carbon is muddied by studies (1) lacking longitudinal
 data, (2) ignoring bulk density changes, or (3) sampling only surface
 soils. To better understand soil organic carbon trends, here we measured
 changes over 30 years in density-corrected, full-soil-depth (90 cm) soil
 organic carbon stocks under 6 cropping systems and a restored prairie in a
 Mollisol of southern Wisconsin, USA. Cash-grain systems and alfalfa-based
 systems lost soil organic carbon. Prairie and rotationally-grazed pasture
 maintained soil organic carbon. Average soil organic carbon 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 soil organic carbon improvements. Our findings
 using more comprehensive methods demonstrate the inadequacy of row-crop
 systems and the need for well-managed grasslands to protect soil organic
 carbon in productive agricultural soils of the Upper Midwest USA.
description: # Soil carbon maintained by perennial grasslands over 30 years but lost in
 field crop systems in a temperate Mollisol
 [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 used to analyze the data using a linear mixed effects model is available in the Supplementary Information of the associated manuscript. ## Changes since initial upload June 25, 2024: Title changed to reflect a change in the title of the manuscript. June 25, 2024: %N column removed from dataset due to possible errors in 1989 data. %N data was not used in the manuscript. July 10th, 2024: Changes to the 1989 data were made to correct for erroneously labeled GPS data. This change minorly impacts the 1989 %C, 1989 BD, 2009 SOC_Mg_ha, and 2019 SOC_Mg_ha values, but does not change the SOC trends between systems and over time. August 12, 2024: %N, phase, and crop1 columns were removed; they were not used in the manuscript connected to this dataset. Cropping system names "ldp" and "hdp" were changed to "prairie" to more accurately reflect the way system was treated in the statistical analysis. "Notes_complete" tab was updated to reflect these changes.