| 引用本文: | 杨昌,王健,李建德,等.土壤表层结皮失水裂缝形态发育规律研究[J].灌溉排水学报,0,():-. |
| YANG Chang,WANG Jian,LI Jiande,et al.土壤表层结皮失水裂缝形态发育规律研究[J].灌溉排水学报,0,():-. |
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| 摘要: |
| 【目的】为明确坡耕地条件下土壤物理结皮失水裂缝开裂规律。【方法】本研究采用室外人工模拟降雨试验，结合MATLAB图像处理功能，对结构结皮、沉积结皮和过渡带结皮物理性质及裂缝网络发育进行了定量分析，并探讨了裂缝形态特征随土壤水分损失的变化情况。【结果】结果表明，不同类型结皮土壤物理性质差异显著，其中结皮体积质量及黏粒质量分数均表现为沉积结皮（DC）最高，其次为过渡带结皮（TZ）、结构结皮（SC）；而砂粒质量分数则表现为结构结皮高于过渡带结皮和沉积结皮。垄沟区域不同部位土壤结皮干缩裂缝形态特征存在显著差异，其中裂缝面积率（RC）、裂缝长度密度（LC）和裂缝平均宽度（Wi）均表现为沉积结皮（DC）＜过渡带结皮（TZ）＜结构结皮（SC），各区域间的连通性指数（K）差异不显著。裂缝形态差异主要受土壤物理性质、含水率下降速率和初始含水率影响，同时结构结皮裂缝形态特征还与其特有的弧状结构有关。裂缝发育过程中，结构结皮、沉积结皮的裂缝面积率、长度密度和平均宽度随含水率降低而增大，裂缝发育完成时，结构结皮的土壤含水率为11.88%，沉积结皮的土壤含水率为20.57%，同时沉积结皮裂缝的发育历时最长为357 h。【结论】表明结皮类型对裂缝发育产生了重要影响，结构结皮裂缝开裂最为明显，沉积结皮裂缝形态复杂多样且发育历时最长。 |
| 关键词: 结皮;干缩裂缝;土壤含水率;微地形 |
| DOI： |
| 分类号:S152.7 |
| 基金项目:坡耕地微地形水力连通性及入渗机理研究 |
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| Study on the Regularity of Morphological Development of Cracks in Soil Crust after a Loss of Water |
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YANG Chang1, WANG Jian2, LI Jiande1, XU Feifei1
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1.Institute of Soil and Water Conservation,Northwest A F University,Yangling;2.College of Resources and Environment,Northwest A F University,Yangling
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| Abstract: |
| 【Objective】 To define the cracking rules of cracks on the crust of slope farmland, based on the outdoor test, this study analyses the physical properties of different types of crusts.【Method】At the same time, combined with the image processing function of MATLAB, the development rules of the crack network of different types of crusts were quantitatively analyzed and the change of the morphological characteristics of the crack with the moisture loss of soil was discussed.【Result】The results show that the physical properties of different types of soil crusts have significant differences. Among them, the depositional crust (DC) has the biggest volume weight and the highest content of clay grains, and the content of sand particles of the structural crust (SC) is higher than that of the crust in the transitional zone (TZ) and the depositional crust (DC). The morphological characteristics of desiccation cracks on soil crusts in different parts of the gully area also have significant differences. Among them, the rate of crack area (RC), the length density of crack (LC), and the average width of crack (W_i) meet the following rule: depositional crust (DC)＜transitional zone (TZ)＜structural crust (SC). The difference in the connectivity index (K) of different areas is not significant. The form of the crack difference is mainly affected by the physical properties of crusts, the decrease rate of the moisture content and the initial moisture content. At the same time, the morphological characteristics of cracks on the structural crust are also related to their unique arch-like structure. The relevant analysis shows that RC, LC, and W_i of structural crust and depositional crust increase with the decrease of the moisture content. After the development of the crack is completed, the minimum moisture content of soil of the structural crust is 11.88% and the maximum moisture content of soil of the depositional crust is 20.57%. At the same time, the maximum duration of the development of the crack on the depositional crust is 357 hours.【Conclusion】indicating that the type the crust has an important impact on the development of cracks. The crack of structural crust is the most obvious, and the crack shape of depositional crust is complex and takes the longest time to develop. |
| Key words: crust; cracks; soil moisture content; microtopography |
