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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孙尚贵1, 雷文娟1, 周向阳2,3
关键词:  饱和导水率;黄壤草坪;雨水花园;土壤颗粒
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);
Decrease patterns of the saturated hydraulic conductivity of astrolawn rain garden of yellow soil and the identification of key affecting soil particles
Sun Shanggui,Lei Wenjuan,Zhou Xiangyang
Guizhou University
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