Continuous decrease in soil organic matter despite increased plant productivity in an 80-years-old phosphorus-addition experiment

This study investigated the long-term effects of tillage and phosphorus addition on soil element dynamics in an 80-year-old cropland experiment in Europe. Despite a significant increase in crop yields over the study period, soil total organic carbon (TOC) and total organic phosphorus stocks decreased by 13.7% and 11.6%, respectively, in the uppermost 20 cm of soil. Modeling of the 14C:12C ratio indicated a mean carbon transit time below 10 years, suggesting rapid respiration of carbon inputs. The findings highlight the unsustainable nature of current agricultural practices, leading to continuous soil organic matter depletion despite increased plant productivity.

Marie Spohn, Sabina Braun, Carlos A. Sierra