Data for: Soil Nutrients Increase Long-term Soil Carbon Gains Threefold on Retired Farmland

These data report soil C for almost four decades following intensive agricultural soil disturbance along an experimentally imposed gradient in nitrogen (N) added annually in combination with other macro- and micro-nutrients. Data were collected at the Cedar Creek Ecosystem Science Reserve (CCESR), a U.S. Long Term Ecological Research (USLTER) site located in central Minnesota, USA. Soil % C accumulated over the course of the study in unfertilized control plots leading to a gain of 6.1 Mg C ha-1 in the top 20 cm of soil. Nutrient addition increased soil % C accumulation leading to a gain of 17.8 Mg C ha-1 in fertilized plots, nearly a threefold increase over the control plots. These results demonstrate that substantial increases in soil C in successional grasslands following agricultural abandonment occurs over decadal timescales, and that C gain is increased by high supply rates of soil nutrients. In addition, soil % C continued to increase for decades under elevated nutrient supply, suggesting that short-term nutrient-addition experiments underestimate the effects of soil nutrients on soil C accumulation.