ABSTRACT
Long-term mono-conservation tillage may not meet the needs to improve soil organic carbon (SOC) sequestration and soil structure stability. A 12-year field experiment was conducted in Northwest China to explore the mechanisms of tillage for improving SOC sequestration, humic substances and soil structure. Rotational tillage, no-tillage and subsoiling increased wheat yield, maize yield and crop residue C by 3%–15%, 8%–15% and 4%–15%, respectively. Meanwhile, rotational tillage, no-tillage and subsoiling increased the conversion rate of crop residue C, resulting in 25%–73% higher SOC sequestration than plowing. Fulvic acid, humic acid and SOC were increased by no-tillage at 0–0.1 m depth, by subsoiling at 0–0.1 m and 0.2–0.4 m depths and by rotational tillage at 0–0.4 m depths. Humic acid and fulvic acid improved soil aggregation. No-tillage increased mean weight diameter (MWD) at 0–0.1 m depth. Rotational tillage and subsoiling improved aggregate stability at 0–0.4 m depths. Due to higher aggregate stability, rotational tillage, no-tillage and subsoiling increased SOC concentrations within macroaggregate and microaggregate, contributing to SOC sequestration. No-tillage rotated with subsoiling had the highest crop yield, SOC stock and MWD, which was the optimal practice in Northwest China.
Acknowledgements
This work was supported by the Special Fund for Agro-scientific Research in the Public Interest of the Ministry of Agriculture, China [201503116].
Disclosure statement
No potential conflict of interest was reported by the author(s).