Tillage system change affects soil organic carbon storage and benefits land restoration on loess soil in <scp>N</scp> orth <scp>C</scp> hina

Soil organic carbon (SOC) is a core indicator of soil quality. A proper tillage system can improve SOC accumulation and benefit land restoration. This improvement is especially significant in loess soil, which is undergoing serious degradation in China. In this study, we chose a field that was used for crop production and used a traditional moldboard plow with crop residue removal (CT) for over 10 years. We then carried out a long‐term field experiment (2007–2015) and changed the tillage system from a moldboard plow with crop residue removal to either a moldboard plow with buried straw system (BT), a no‐tillage with straw mulch system (NT), or a subsoiling with straw mulch system (ST) to evaluate the effect of tillage system change and the effects of tillage systems on SOC storage. Tillage system change influenced SOC content, NT, ST, and BT showed higher values of SOC content and increased 8.34, 7.83, and 1.64 Mg·C·ha −1 , respectively, compared with CT. Among the 3 changed tillage systems, NT and ST showed a 12.5% and 11.6% increase in SOC content then BT, respectively. Tillage system change influenced SOC stratification ratio values, with higher value observed in BT and NT compared CT but ST. Therefore, in loess soil, changing tillage system can significantly improve SOC storage and change profile distribution. The NT and ST treatments showed a more marked SOC increase, but the increase value in stratification ratio with NT still needs attention, and our results is meaningful for soil quality improvement and land restoration.