During freeze–thaw cycling, aggregates undergo a dynamic change in breakdown–formation (turnover), however, how the turnover occurs between aggregates of various particle sizes is not clear. To clarify the influence of freeze–thaw cycling on the dynamic changes in the particle size of soil aggregates, soil aggregates from the Black Soil Region of Northeast China were selected as the research objects. The study conducted in situ dynamic monitoring experiments, innovatively applying the rare earth oxide (REO) tracer method to natural conditions of freeze–thaw cycles (autumn freeze–thaw period, freezing period, and spring freeze–thaw period), accurately tracking the turnover paths and quantifying the turnover rates between aggregates of various particle sizes. The results revealed that the total value of the formation paths of the 2–5 mm aggregates and 0.25–2 mm aggregates increased during the autumn freeze–thaw period. The number of freeze–thaw cycles and accumulated snowfall were significantly positively correlated with aggregate stability, with an increase in the number of freeze–thaw cycles and accumulated snowfall resulting in an increase in the proportion of aggregates > 0.25 mm, which improved aggregate stability. In addition, the total value of the breakdown path of macro-aggregates increased during the spring freeze–thaw cycling period. Soil moisture was significantly negatively correlated with aggregate stability, with increased soil moisture resulting in a decrease in the percentage of aggregates > 0.25 mm, which resulted in a decrease in aggregate stability. The study can provide a reference understanding for the effects of freeze–thaw cycles on the structure of black soil and provide a theoretical basis for improving the quality of arable land.

中文翻译：

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冻融循环对黑土团聚体稳定性和周转的影响


在冻融循环过程中，聚集体在分解形成（周转）方面发生动态变化，但是，各种粒径的聚集体之间如何发生周转尚不清楚。为明确冻融循环对土壤团聚体粒径动态变化的影响，以东北黑土区土壤团聚体为研究对象。该研究进行了原位动态监测实验，创新性地将稀土氧化物 （REO） 示踪剂方法应用于冻融循环的自然条件（秋季冻融期、冻结期和春季冻融期），准确跟踪周转路径并量化各种粒径聚集体之间的周转率。结果表明，在秋季冻融期间，2-5 mm 聚集体和 0.25-2 mm 聚集体的形成路径总值增加。冻融循环次数和累积降雪量与团聚体稳定性呈显著正相关，冻融循环次数和累积降雪量的增加导致团聚体比例增加 > 0.25 mm，从而提高了团聚体稳定性。此外，在春季冻融循环期间，宏观聚集体击穿路径的总值增加。土壤水分与团聚体稳定性呈显著负相关，土壤水分增加导致团聚体百分比 > 降低 0.25 mm，从而导致团聚体稳定性降低。该研究可为冻融循环对黑土结构的影响提供参考认识，为提高耕地质量提供理论依据。