Cation ratio of soil structural stability (CROSS) is preferred over sodium adsorption ratio (SAR) for assessing irrigation water quality. However, its applicability in evaluating the impact of high-CROSS saline water on soil cracking remains unknown, as previous studies have focused solely on clay particle dispersion and flocculation. This study aims to determine whether high-CROSS saline water, with identical EC values, induces soil cracking and to identify the CROSS thresholds that trigger it. An indoor soil column test was conducted to analyze soil clay dispersion, macropores, and crack alterations after 12 wet and dry cycles. Saline water with the same EC of 4 dS m, and different cation compositions (thus different CROSS levels) of Na-Mg (NM100), Na-K-Mg (NKM67), Na-Ca-Mg (NCM38), Na-Ca (NC28) and K-Ca (KC9) (the figure of each treatment’ name represents the value of optimal CROSS (CROSS)), respectively. Results indicated that soil suspension turbidity increased with rising CROSS. When CROSS surpassed a specific threshold, it led to soil cracking, with crack angles transitioning from horizontal to vertical with increasing CROSS. Notably, NKM67 induced significant vertical crack formation. In NM100, intersecting vertical and horizontal cracks led to a drastic drop in macropore numbers, with narrow cracks evolving into those with smaller aspect ratios. While KC9's crack volume was about 5% of its macropore volume, crack volumes in NC28, NCM38, and NKM67 were nearly the same as their macropore volumes. However, NM100's crack volume was about 60 times its macropore volume. Independent pores remained below 20% of connected pores, with KC9 primarily comprising connected macropores, while NM100 had connected cracks. However, the results obtained in this study are soil-specific and might vary depending on soil texture and mineral types in other regions. More comparative studies on various soils are recommended for general use in the future. At all events, these findings provide a new inspiration for studying the safe utilization of saline water and preserving soil quality.

中文翻译：

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盐水的阳离子组成通过改变伊利石土壤中大孔和裂缝的形成来影响土壤结构

在评估灌溉水质时，土壤结构稳定性阳离子比 (CROSS) 优于钠吸附比 (SAR)。然而，其在评估高交叉盐水对土壤开裂的影响方面的适用性仍然未知，因为以前的研究仅集中在粘土颗粒的分散和絮凝上。本研究旨在确定具有相同 EC 值的高 CROSS 盐水是否会引起土壤开裂，并确定触发它的 CROSS 阈值。进行室内土柱试验，分析 12 次干湿循环后的土壤粘土分散、大孔和裂缝变化。具有相同 EC 4 dS m 的盐水，以及 Na-Mg (NM100)、Na-K-Mg (NKM67)、Na-Ca-Mg (NCM38)、Na-Ca 的不同阳离子组成（因此不同的 CROSS 水平） （NC28）和K-Ca（KC9）（每个处理名称的数字代表最佳CROSS值（CROSS））。结果表明，土壤悬浮液浊度随着CROSS的增加而增加。当 CROSS 超过特定阈值时，会导致土壤开裂，随着 CROSS 的增加，裂缝角度从水平过渡到垂直。值得注意的是，NKM67 诱发了显着的垂直裂纹形成。在NM100中，垂直和水平裂缝的交叉导致大孔隙数量急剧下降，狭窄的裂缝演变为纵横比较小的裂缝。KC9 的裂缝体积约为其大孔体积的 5%，而 NC28、NCM38 和 NKM67 的裂缝体积与其大孔体积几乎相同。然而，NM100的裂纹体积约为其大孔体积的60倍。独立孔隙仍低于连通孔隙的20%，其中KC9主要由连通大孔组成，而NM100则存在连通裂缝。然而，本研究获得的结果是针对特定土壤的，可能会因其他地区的土壤质地和矿物类型而有所不同。建议将来对各种土壤进行更多比较研究以供一般使用。无论如何，这些发现为研究咸水的安全利用和保护土壤质量提供了新的启发。