Perennial cropping systems increased topsoil carbon and nitrogen stocks over annual systems—a nine-year field study

Summary

Enhancing biomass yield simultaneously with soil carbon (C) sequestration is a key aim of climate-smart cropping systems. Perennialization is believed to be a suitable mitigation strategy for climate change with the potential for enhancing soil C stocks. Based on a nine-year field experiment in Denmark, we measured the changes in soil C and nitrogen (N) stocks, biomass yield, and yield stability of three perennial (low-fertilized miscanthus, high-fertilized festulolium, and no N-fertilized grass-legume mixture) and two annual (continuous triticale and maize) cropping systems. We found that the changes in topsoil (0–20 cm) and 0–100 cm soil C stocks and topsoil N stocks varied significantly between cropping systems. Over nine years, topsoil C stocks increased by an average of 1.4 Mg C ha−1