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Chinese Agricultural Science Bulletin ›› 2024, Vol. 40 ›› Issue (23): 53-59.doi: 10.11924/j.issn.1000-6850.casb2024-0080

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Effect of Freeze-thaw Cycles on Distribution of Soil Aggregates and Their Organic Carbon Content in Arable Mollisol

ZHU Shuai1(), LI Shiyong1, JIANG Boyu1, ZHAO Wenyi1, ZHAO Maojie1, CHEN Yimin2, SUI Yueyu2, JIAO Xiaoguang1()   

  1. 1 College of Modern Agriculture and Ecological Environment, Heilongjiang University, Harbin 150080
    2 Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Harbin 150081
  • Received:2024-01-22 Revised:2024-06-24 Online:2024-08-09 Published:2024-08-09

Abstract:

To investigate the impact of freeze-thaw cycles on soil aggregates and bound carbon in arable mollisol, this study took arable mollisol in Hailun, Heilongjiang Province as the research object. Incubation experiments were conducted to investigate the impact of freeze-thaw frequency on soil aggregates and organic carbon content of arable mollisol at three temperatures: -9, -18 and -26℃. The results indicated that the content of 1-0.5 mm and 0.25-0.053 mm aggregates exhibited significant changes at all three freeze-thaw temperatures with an increase of freeze-thaw frequencies (P<0.05). Compared with single freeze-thaw cycle, after 17 freeze-thaw cycles at the same temperature, the content of 1-0.5 mm aggregates decreased by 68.53%, 10.91% and 40.96% at -9, -18 and -26℃, respectively. The content of 0.25-0.053 mm aggregates increased by 10.93%, 40.89% and 99.72%, respectively. At -9℃, the fractal dimension of soil aggregates significantly increased (P<0.05) from 2.09 to 2.74, while at -18℃ and -26℃, the changes were small, with changes of 0.1 and 0.05, respectively. The bound carbon of soil aggregates did not show significant changes with the increase of freeze-thaw frequency (P>0.05). At -18℃ and -26℃, the <0.053 mm aggregate showed a gradual decreasing trend, with a decrease of 10.31% and 13.73% after 17 freeze-thaw cycles, respectively. The freeze-thaw impact could significantly reduce the stability of soil aggregates in arable mollisol. The increasing freeze-thaw cycles can significantly reduce the content of aggregates by 1-0.5 mm and increase the content of aggregates by 0.25-0.053 mm(P<0.05). Both freeze-thaw frequency and temperature were important factors affecting the stability of soil aggregates.

Key words: freeze-thaw cycles, soil aggregates, aggregates stability, aggregates bound organic carbon, freeze-thaw action, organic carbon, soil physicochemical properties, soil management, ecosystem restoration