不同孔隙度土壤气体扩散系数测定

被引：8

作者：

苏志慧

吴兵

龚元石

机构：

[1] 中国农业大学资源与环境学院土壤与水科学系

来源：

农业工程学报 | 2015年 / 31卷 / 15期

关键词：

土壤; 孔隙度; 模型; 气体扩散系数; 充气孔隙度; 测定装置;

D O I：

暂无

中图分类号：

S152.6 [土壤空气];

学科分类号：

0903 ; 090301 ;

摘要：

土壤气体扩散系数是研究土壤气体传输过程的一个重要参数,它随土壤质地、容重和孔隙的改变而变化,难以估算,为准确测定和研究其特征,依据气体扩散原理设计并研制了土壤气体扩散系数测定装置。以石英砂和砂质壤土为试验材料,利用该装置研究了气体扩散系数与不同含水量和容重下的充气孔隙度间的关系。结果表明:砂质壤土原状土和装填土的气体扩散系数差别很小;土壤相对扩散系数随土壤总孔隙度减小而变小,且粒径较小的土壤具有相对较小的气体扩散系数;原状和装填砂质壤土的相对扩散系数与充气孔隙度之间的关系均可以用幂函数方程来拟合,方程中的参数与土壤质地密切相关,原状土非活性孔隙度为0。Buckingham模型的预测值与实测结果基本一致(均方根误差=0.008),但Millington and Quirk模型(均方根误差=0.032)和SWLR模型(均方根误差=0.023)的预测结果偏差较大。

引用

页码：108 / 113

页数：6

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