No-tillage (NT) has been shown to control soil degradation by impacting soil aggregates (i.e., basic units of soil structure, whose characteristics mediate key soil processes, like carbon sequestration). However, there has been no systematic analysis of the impacts of NT on soil aggregation and aggregate-associated soil organic carbon (SOC) at global level. We conducted a global meta-analysis of 89 publications to elucidate the changes in soil aggregation and aggregate-associated SOC under NT. Notably, we quantified the roles of diverse environmental and agronomic factors (e.g., climatic conditions, experimental duration, cropping intensity, soil texture, and initial SOC/pH) in the changes in those variables. Relative to conventional tillage (CT), NT significantly increased the proportions of water-stable large (LM) and small (SM) macro-aggregates and the mean weight diameter (MWD) (by 49%, 11%, and 23%, respectively) but decreased the proportions of micro-aggregates (MIC) and silt plus clay-size particles (SC) (by 11% and 16%, respectively). NT significantly enhanced SOC concentrations in LM (17%), SM (14%), MIC (10%), and SC (7%) compared to CT. Furthermore, the random forest (RF) model demonstrated that climatic conditions, experimental duration, and soil texture were the predominant factors controlling the changes in aggregation and aggregate-associated SOC under NT. Overall, our results indicate that NT is an effective strategy to enhance soil aggregation and aggregate-associated SOC, yet variations in responses are determined by specific environmental/agronomic factors. This study provided a basis for identifying site-specific NT practice that could help improve soil structure and SOC sequestration, ultimately controlling soil degradation in croplands.

中文翻译：

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免耕对土壤团聚和团聚体相关有机碳影响的全球荟萃分析

免耕 (NT) 已被证明可以通过影响土壤团聚体（即土壤结构的基本单位，其特征调节关键土壤过程，如碳固存）来控制土壤退化。然而，在全球范围内，还没有系统分析 NT 对土壤团聚和与团聚体相关的土壤有机碳 (SOC) 的影响。我们对 89 篇出版物进行了一项全球荟萃分析，以阐明 NT 下土壤聚集和与聚集体相关的 SOC 的变化。值得注意的是，我们量化了各种环境和农艺因素（例如，气候条件、实验持续时间、种植强度、土壤质地和初始 SOC/pH 值）在这些变量变化中的作用。相对于常规耕作（CT），NT 显着增加了水稳定性大 (LM) 和小 (SM) 大团聚体的比例以及平均重量直径 (MWD)（分别增加了 49%、11% 和 23%），但降低了微团聚体的比例。聚集体 (MIC) 和淤泥加粘土大小的颗粒 (SC)（分别增加 11% 和 16%）。与 CT 相比，NT 显着提高了 LM (17%)、SM (14%)、MIC (10%) 和 SC (7%) 中的 SOC 浓度。此外，随机森林 (RF) 模型表明，气候条件、实验持续时间和土壤质地是控制 NT 下聚集和聚集体相关 SOC 变化的主要因素。总的来说，我们的结果表明 NT 是增强土壤聚集和与聚集体相关的 SOC 的有效策略，但响应的变化取决于特定的环境/农艺因素。