| 引用本文: | 孙尚贵,雷文娟,周向阳.黄壤草坪雨水花园饱和导水率衰减特征及关键土壤颗粒识别[J].灌溉排水学报,0,():-. |
| Sun Shanggui,Lei Wenjuan,Zhou Xiangyang.黄壤草坪雨水花园饱和导水率衰减特征及关键土壤颗粒识别[J].灌溉排水学报,0,():-. |
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| 摘要: |
| 黄壤是中国西南喀斯特区域的典型土壤，其黏粒含量高、孔隙度小、透水性差等特征导致城市洪水风险较高。雨水花园能够有效地提高土壤渗透性，但随着运行时间的增加，其渗透性的衰减规律变化及起关键作用的土壤颗粒及其空间分布尚不清楚。因此，研究通过定水头入渗实验测定了2-4年黄壤草坪雨水花园饱和导水率(Ks)的动态变化特征，同时以2cm为间隔测量了表层0-10cm不同土层的土壤颗粒粒径分布曲线，并通过模型回归识别了导致Ks显著降低的关键土壤颗粒及其分布位置和土层厚度，对比了不同年限雨水花园的特征差异。结果表明：（1）导致2-4年雨水花园Ks降低的关键土壤颗粒分别是细砂(100-250μm)、极细砂(50-100μm)和粉粒(2-50μm)，并可用指数衰减模型进行描述(R2=0.99)；（2）这些关键土壤颗粒位于3-7cm深度且土层厚度为3-5cm，而不是在质地最粗的表层和黏粒含量最高的底层。研究结果将为从细观尺度揭示黄壤天然雨水花园渗透性衰减的物理机制和关键过程提供参考依据。 |
| 关键词: 饱和导水率;黄壤草坪;雨水花园;土壤颗粒 |
| DOI： |
| 分类号:TV93 |
| 基金项目:国家自然科学基金(41701558;51969006)；贵州省科技计划项目(黔科合支撑[2019]2875; [2018]5781-45; RCJD2018-21)； |
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| Decrease patterns of the saturated hydraulic conductivity of astrolawn rain garden of yellow soil and the identification of key affecting soil particles |
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Sun Shanggui,Lei Wenjuan,Zhou Xiangyang
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Guizhou University
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| Abstract: |
| Yellow soil, the typical Oxisols and the main arable lands in the karst area of southwestern China, features a high content of clay, small porisity and poor water permeability that lead to a higher risk of urban flood. Rain gardens can improve soil permeability effectively, but what the decay patterns of permeability are and which soil particles play the key role of reducing the permeability during a infiltration process are not clear. Therefore, this study measures the dynamic decrease of saturated hydraulic conductivity, Ks, through the infiltration experiment with constant waterhead, meanwhile the vertical change of the soil particle distributions are measured at the interval of 2cm; then the key soil particles are identified by the correlation of coefficient through the regression analysis based on several simple functions, and the location of these key particles and the thickness of the key layers are also identified; and finally the differences are compared among the rain gardens with the age of 2-4 years. The results indicate that the key soil particles reducing the saturated hydraulic conductivity is fine sand, very fine sand and silt for the astrolawn rain garden with the age of 2, 3 and 4 years respectively, and the correlation can be well fitted by an exponential decrease model with the R2 of 0.99. Besides, these key soil particles are mainly located at the depth of 3-7 cm with the thickness of 3-5 cm, because the downward migration of the soil particles driven by water flow and the coarser size particles deposit in the upper layer and then blocks the pores. These results provide a deeper insight from the perspective of microscopic and mesoscopic scale into understanding the theoretical mechanisms of the decreasing permeability of the astrolawn rain garden of yellow soil during the infiltration process, and are also helpful in the routine management of these rain gardens. |
| Key words: Saturated hydraulic conductivity; Key soil particle; Astrolawn rain garden; Yellow soil |
