| Cite this article: | 夏天,田军仓.基于沙壤土粘粒量预测土壤入渗量和湿润峰深度[J].灌溉排水学报,0,():-. |
| XIA Tian,TIAN Juncang.基于沙壤土粘粒量预测土壤入渗量和湿润峰深度[J].灌溉排水学报,0,():-. |
|
| |
|
|
| This article has been：Browse 1694Times Download 0Times |
|
|
|
| DOI： |
|
| Predicting Cumulative Infiltration and Wetting Front Distance of Sandy Loam Soil Using Clay Content as an Indicator |
|
XIA Tian1, TIAN Juncang1,2
|
|
1.College of Civil and Hydraulic Engineering,Ningxia University;2.Ningxia Research Center of Technology on Water-saving Irrigation and Water Resources Regulation
|
| Abstract: |
| Abstract: The one-dimensional, vertical infiltration into soil with the surface of which ponded with a depth of free water is one of the most commonly encountered forms of infiltration. The measurement for cumulative infiltration and the advance of wetting front have been carried out for many years. Studies on soil water infiltration have been focused on theoretical and experimental aims. For theoretical study, researchers mainly focused on some infiltration models i.e. physical, semi-empirical, and empirical. Physical models based on Darcy’s law and law of mass conservation include the Green-Ampt model, Philip model, and Richards equation. Semiempirical models based on some simple hypotheses include Horton model and Singh and Yu model. Empirical models based on field observed data mainly include Kostiakov model and improved Kostiakov model. For experimental study, researchers mainly focused on soil texture, structure, bulk density, organic content, water content, temperature, and some other factors that influence the infiltration characteristics of soil. For texture variables on soil infiltration characteristics, the clay content has been considered as the indicator for soil texture by some researchers. Main results obtained are as follows: 1) the steady-state infiltration rate shows negative correlation with clay content by a power function relationship; 2) the sorptivity and steady-state infiltration rate shows a negative correlation with clay content by a logarithmic function. Despite the above results, problems arise that it may not be in accordance with the actual infiltration process in natural conditions by adopting the above model forms. For example, the calculated values for soptivity or the steady-state infiltration rate may be divergent when the clay content is approaching zero, when the above forms of model have been adopted for curve fitting. 【Objective】The aim of this study is to derive the models for predicting the cumulative infiltration and wetting front distance of sandy loam soil using clay content as an indicator.【Method】Totally 11 mass percentage treatments of combined sandy loam soils were designed. Influence on cumulative infiltration and wetting front distance of sandy loam soil posed by the clay content under the same dry bulk density was studied by ponded infiltration experiments using soil column in the laboratory. 【Result】Results show that under the dry bulk density of 1.41g/cm3, while the clay content increases from 4.51% to 12.03%, the time span for wetting front reaching the depth of 45cm increases from 103 min to 310 min, relatively increasing 2 times. At the same time, the cumulative infiltration decreases from 8 cm to 1 cm, relatively decreasing about 87.5%. In addition, the relation between the coefficient of model describing relationship between wetting front and time and the clay content, as well as that between parameters of model describing relationship between cumulative infiltration and time including sorptivity and the steady-state infiltration rate and clay content, can all be well described using exponential decay models with adjusted square higher than 0.968.【Conclusion】The derived predicting models are examined to be of high accuracy. Quick predictions for wetting front and cumulative infiltration of sandy loam soil can be obtained with the absolute error less than 10%. |
| Key words: sandy loam soil; infiltration; clay content; steady-state infiltration rate; predicting model |
|
|
|
|
|
|
