Soil carbon maintained by perennial grasslands over 30 years but lost in field crop systems in a temperate Mollisol

Analysis of three decades of deep SOC data from the Wisconsin Integrated Cropping Systems Trial, SOCnets Tier 1 "hub" in Wisconsin. In addition to covering SOC dynamics in Midwestern farming system the study performes a sensitivity analysis to investigate the impacts of divergent methodological approaches from those that are ubiquitous but insufficient to the comprehensive methods being used in SOCnet (time-series, ESM, deep cores, etc.). To date this publication is one of the most comprehensive evaluations of long-term deep SOC in Midwestern Mollisols. As a foundational paper for the SOCnet project this begins to address some of our key initial questions and lays the groundwork for anlaysis of the on-farm data (Tiers 2 & 3).