中国生态农业学报2018，Vol.26Issue(4)：593-603,11.DOI:10.13930/j.cnki.cjea.170450
土壤垂向分层和均匀处理下水分差异的数值探讨
Numerical difference in soil water between vertically stratified and homogenized soil profiles
摘要
Abstract
For many land surface process models, soil moisture is described quantitatively by assuming that its vertical distri-bution is uniform and that the upper soil texture is representative of the whole soil profile. There are differences in soil mois-ture between stratified and homogenous soils, which have been little documented so far in research. By setting up three strati-fied soil groups with different soil hydraulic conductivity combinations and using the upper soils as representative of the soil profiles of the three stratified soil groups, one-dimensional soil water movement model was established to analyze the differ-ences in soil moisture. At the same time, the sensitivities of five parameters (including saturated hydraulic conductivity, satu-rated water content, residual moisture content, pore size distribution and particle shape) to the differences in leakage and water storage between stratified and homogenous soils were analyzed. It was found that: 1) soil water profile simulated by the one-dimensional soil water movement model was consistent with that simulated by Yeh Analytical Solution and also that by Water Transformation Dynamical Processes Experimental Device (WATDPED) experiment. This proved that the model was reliable irrespective of whether root water uptake was considered or not. 2) The greater the difference in saturated hydraulic conductivity between upper and lower soils, the greater the difference in hydrological variables of homogeneous and stratified soils. When saturated hydraulic conductivity of the upper soil was 1.5 times that of the lower soil, the difference in soil mois-ture distribution between stratified and homogeneous soils was less than 0.05 cm3?cm-3. When it was 3.3 times, the differences in soil moisture, leakage and water storage were 0.15 cm3?cm-3, 20 cm and 5 cm, respectively. 3) Compared with the lower layer of stratified soil, water holding capacity of the lower layer of homogeneous soil was lower and with water outflow was faster, which resulted in lower moisture distribution, higher leakage and lower storage capacity in lower layer of homogeneous soil. 4) Soil particle shape (n) was the most sensitive parameter to leakage. Then pore size distribution was the most sensitive parameter to water storage, followed by soil particle shape n. In reality, if upper and lower soil saturated hydraulic conductivi-ties differed largely, homogeneous treatment induced significant errors, differing greatly from actual soil moisture distribution in the layers. This heavily affected the accurate estimation of soil moisture, which required a realistic consideration of the use of this practice.关键词
土壤非均匀性/垂向均匀土壤/土壤水分运动模型/渗漏量/储水量/敏感性分析/Yeh解析解/室内水转化动力过程试验Key words
Soil heterogeneity/Vertical homogeneityous soil/Soil water movement model/Leakage/Soil water storage/Sensitivity analysis/Yeh analytical solution/Water Transformation Dynamical Processes Experimental Device分类
农业科技引用本文复制引用
熊丁晖,刘苏峡,莫兴国..土壤垂向分层和均匀处理下水分差异的数值探讨[J].中国生态农业学报,2018,26(4):593-603,11.基金项目
国家重点基础研究发展计划(973计划)项目(2012CB957802)、国家重点研发计划项目(2016YFC0401402)和国家自然科学基金项目(41471026)资助 This study was funded by the National Key Basic Research and Development Program of China (973 Plan) (2012CB957802), the National Key Research and Development Program of China (2016YFC0401402) and the National Natural Science Foundation of China (41471026). （973计划）
