Pedosphere 36(5): 1163--1176, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Long-term effects of cropping regimes on soil organic carbon and aggregate stability in a Mollisol of Northeast China |
Cuilan LI1, Zhiyuan CAO1, Mo ZHU2 , Hongjun GAO3, Xiuzhi ZHANG3, Ping ZHU3, Jinjing ZHANG1 |
1 College of Resources and Environment, Jilin Agricultural University, Changchun 130118 (China);
2 Institute of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun 130033 (China);
3 Institute of Agricultural Resource and Environment, Jilin Academy of Agricultural Sciences, Changchun 130033 (China) |
| ABSTRACT |
| Designing cropping regimes that enhance soil carbon (C) stocks while maintaining soil quality and adequate food production levels is crucial for achieving the sustainable use of soil resources. Despite extensive knowledge of the effects of cropping regimes on soil organic C (SOC) accumulation and structural stability, the underlying mechanisms are unclear. In this study, a 28-year field experiment was conducted to evaluate the influences of different cropping systems on SOC content and chemical composition, soil aggregate size distribution and stability, and organic C (OC) content in soil aggregate fractions in a Mollisol (black soil) in Northeast China. The field experiment was composed of six treatments: monoculture (continuous maize cropping (CMC) and continuous soybean cropping (CSC)), rotation (maize-maize-soybean (MMSR), maize-soybean-maize (MSMR), and soybean-maize-maize (SMMR) rotation), and farmland fallow (FALL). Farmyard manure was applied annually to each treatment, except for FALL. Compared with FALL, monoculture and rotation significantly (P < 0.05) increased bulk SOC content, aromatic C, proportion of microaggregates, and microaggregate- and silt + clay fraction-associated OC contents. However, monoculture and rotation significantly (P < 0.05) decreased oxygen-alkyl C, the proportion of macroaggregates, and mean weight diameter (MWD) of aggregates. The SOC content, proportion of large macroaggregates, MWD of aggregates, macroaggregate-associated OC content, and newly formed large macroaggregate-associated OC content were all significantly (P < 0.05) higher under SMMR than under the monoculture and other rotation systems. Structural equation modeling revealed that monoculture and rotation affected bulk SOC content and aggregate stability owing to their regulation of soil nutrients, aggregation, aggregate-associated OC, and SOC chemical composition. The results suggested that long-term fallow was not favorable for SOC accumulation but maintained SOC structural stability. In contrast, with soybean rather than maize as a pre-crop, the long-term maize-soybean rotation with manure amendment was most beneficial for enhancing both SOC accumulation and structural stability among the monoculture and rotation systems. The physical protection of SOC (especially newly formed SOC) by macroaggregates was the main mechanism for SOC accumulation under SMMR. This research aids in establishing a sustainable cropping regime that can improve organic matter and stabilize aggregates in cultivated soils. |
| Key Words: aggregate-associated organic carbon,black soil,carbon accumulation mechanism,macroaggregate,monoculture,rotation,soil aggregation,stable carbon isotope composition |
| Citation: Li C L, Cao Z Y, Zhu M, Gao H J, Zhang X Z, Zhu P, Zhang J J. 2026. Long-term effects of cropping regimes on soil organic carbon and aggregate stability in a Mollisol of Northeast China. Pedosphere. 36(5): 1163-1176. |
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