Soil aggregation plays an essential role in maintaining soil structure. A three-year field experiment was undertaken to explore the effects of cover crops on soil aggregate stability indices (mean weight diameter, water-stable aggregates greater than 0.25 mm, and soil erodibility factor), size distribution and their correlations with nine soil physical and chemical properties (soil bulk density, pH, organic carbon, total nitrogen, C/N, calcium, phosphorus, potassium, and cation exchange capacity) at 0–5 and 5–10 cm depths in a Marietta silt loam soil in a no-till field, Northeastern Mississippi. The cover crop treatments included elbon rye ( L.), daikon radish (), Austrian winter field peas (), and their mixture. The samples were wet-sieved to five size classes of aggregates (> 2, 2–1, 1–0.5, 0.5–0.25, and < 0.25 mm). Results showed that the < 0.25 mm aggregates dominated (50.95–78.02 %) soil aggregate size distribution at 0–5 and 5–10 cm depths. The rye plot soil displayed the greatest values for mean weight diameter (0.58 mm) in the two soil depths. Soil water-stable aggregates greater than 0.25 mm value under peas was significantly higher by 68.61 % compared to the no cover crop treatment at 0–5 cm depth, while soil erodibility factor did not change significantly. Mean weight diameter, water-stable aggregates greater than 0.25 mm, soil erodibility factor, 1–0.5 mm aggregates, and < 0.25 mm aggregates were significantly correlated with soil organic carbon, pH, bulk density, phosphorus, and potassium. The dominant factors driving changes in three aggregate stability indices and size fractions (excluding 2–1 mm aggregates) were bulk density and pH. Furthermore, high pH restricted soil aggregate stability and size distribution. This study demonstrated the positive impact of cover crops, specifically peas and rye, on soil aggregate stability and size distribution. This study will provide valuable information for future research on soil stabilization in crop production management systems.

中文翻译：

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免耕地覆盖作物对土壤团聚体稳定性、粒径分布及相关因素的影响


土壤团聚对于维持土壤结构起着至关重要的作用。进行了为期三年的田间试验，探讨覆盖作物对土壤团聚体稳定性指数（平均重量直径、大于 0.25 毫米的水稳定性团聚体和土壤可蚀性因子）、尺寸分布的影响及其与九种土壤物理和化学性质的相关性。玛丽埃塔淤泥壤土 0-5 和 5-10 厘米深度的化学特性（土壤容重、pH、有机碳、总氮、C/N、钙、磷、钾和阳离子交换容量）密西西比州东北部的耕地。覆盖作物处理包括黑麦 (L.)、白萝卜 ()、奥地利冬豌豆 () 及其混合物。将样品湿筛为五个骨料尺寸等级（> 2、2–1、1–0.5、0.5–0.25 和 < 0.25 mm）。结果表明，< 0.25 mm 团聚体在 0-5 和 5-10 cm 深度的土壤团聚体尺寸分布中占主导地位（50.95-78.02%）。黑麦样地土壤在两个土壤深度中显示出平均重量直径的最大值（0.58 毫米）。豌豆下土壤水稳性团聚体值大于0.25 mm，与0~5 cm深度无覆盖作物处理相比显着提高了68.61%，而土壤可蚀性因子没有显着变化。平均重量直径、大于0.25毫米的水稳性团聚体、土壤侵蚀因子、1-0.5毫米团聚体和< 0.25毫米团聚体与土壤有机碳、pH、容重、磷和钾显着相关。驱动三个骨料稳定性指数和尺寸分数（不包括 2-1 mm 骨料）变化的主导因素是堆积密度和 pH 值。此外，高pH值限制了土壤团聚体的稳定性和尺寸分布。 这项研究证明了覆盖作物，特别是豌豆和黑麦，对土壤团聚体稳定性和尺寸分布的积极影响。这项研究将为未来作物生产管理系统中土壤稳定性的研究提供有价值的信息。