Pedosphere 35(2): 373--386, 2025
ISSN 1002-0160/CN 32-1315/P
©2025 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Soil organic carbon and aggregate characteristics in a subtropical cotton production field as influenced by century-long crop rotation and fertility management |
Yuanchang TIAN1,2, Jim J. WANG2 , Shuai LIU2,3, Zhuo WEI2,4, Syam K. DODLA5, Baoyue ZHOU2, Charles C. MITCHELL6, Zengqiang ZHANG1 |
1 College of Natural Resources and Environment, Northwest A&F University, Yangling 712100 (China)
2 School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge LA 70803 (USA)
3 College of Earth Science, Guilin University of Technology, Guilin 541006 (China)
4 Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500 (China)
5 Red River Research Station, Louisiana State University Agricultural Center, Bossier City LA 71112 (USA)
6 Department of Crop, Soil and Environmental Sciences, Auburn University, Auburn AL 36849 (USA) |
| ABSTRACT |
| Understanding long-term effects of agricultural management on soil organic carbon (C) (SOC) dynamics and aggregate stability is essential for crop production sustainability. In this study, effects of crop rotation, cover crop, and nitrogen (N) fertilization on SOC physical and molecular fractions and water-stable aggregate stability were evaluated by characterizing soils of the world’s oldest, century-long (> 120 years) continuous cotton experiment located in the southern USA. Field treatments included continuous cotton with no winter legume and no mineral N fertilizer (control, CK), continuous cotton with winter legume (CWL), cotton-corn rotation with winter legume (CCWL), cotton-corn rotation with winter legume and mineral N fertilizer (CCWLN), and continuous cotton with mineral N fertilizer (CN). Total organic C (TOC), total nitrogen (TN), acid-hydrolysis C (AHC), and water-extractable organic C (WEOC) in both bulk soils and different aggregate fractions were determined. Soil organic matter (SOM) composition was characterized using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results showed that CCWL and CCWLN increased bulk soil TOC, AHC, and TN by 150%-165%, 300%-315%, and 198%-223%, respectively, as well as aggregate-associated C by 180%-246% over CK. The CWL and CN treatments also increased TOC, AHC, and TN compared to CK but to a lesser degree. The CCWL treatment increased macroaggregates (250-2 000 μm) by 92% followed by CCWLN by 46%, whereas CWL and CN had limited effects in increasing macroaggregates (by 1%-7%) compared to CK. Moreover, SOM showed more diversified polysaccharide-derived compounds, aliphatic compounds, aromatic compounds, lignin, and phenols in CCWL and CCWLN followed by CWL, CN, and CK. Across different field treatments, aggregate stability indices, mean weight diameter (MWD) and geometric mean diameter (GMD), were positively related to TOC and TN (R2 = 0.57-0.65), and N-containing compounds and phenols (R2 = 0.71-0.89), as well as polysaccharide-derived and aliphatic compounds (R2 = 0.53-0.71). It was concluded that the diversified inputs of SOM composition brought by synergistic interactions between corn rotation and winter legume inclusion were mainly responsible for the observed TOC accumulation and aggregate formation and stability in these subtropical cotton production systems. |
| Key Words: acid-hydrolysis C,aggregate formation,aggregate stability,cover crop,labile organic C,water-extractable organic C,winter legume |
| Citation: Tian Y C, Wang J J, Liu S, Wei Z, Dodla S K, Zhou B, Mitchell C C, Zhang Z Q. 2025. Soil organic carbon and aggregate characteristics in a subtropical cotton production field as influenced by century-long crop rotation and fertility management. Pedosphere. 35(2): 373-386. |
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