干旱区荒漠戈壁土壤结构参数和热力参数的垂直变化

本文利用 2 0 0 0年 10月 2 7日在西北干旱区敦煌戈壁提取的土壤样本的实验室的测量结果 ,分析了 80cm深度内的土壤组分、土壤容重、土壤湿度、土壤孔隙度等土壤结构参数以及土壤热传导率、土壤热容量、土壤比热和热扩散率等土壤热力参数的垂直分布特征 ,结果发现土壤容重随深度的变化受土壤孔隙度影响比较明显 ,并与土壤孔隙度变化成清楚的反相关 ;受土壤湿度变化的影响则不明显。土壤热传导率、土壤热容量、土壤比热和热扩散率等土壤热力参数的垂直变化与土壤容重和土壤孔隙度等土壤结构参数的变化均有关 ,与前者基本正相关 ,与后者基本负相关 ;与土壤湿度的关系则不明显。这说明土壤容重和土壤孔隙度的变化对土壤热力参数的影响占主导地位。土壤热力参数的实验室测量结果与野外观测结果比较接近 ,验证了野外观测结果的可靠性。

Vertical Change of the Soil Structure Parameters and the Soil Thermodynamic Para meters in the Gobi Deserts in Arid Areas

This paper analyzes the vertical distribution characteristics of the parameters of soil structure, such as the soil constituent, soil bulk density, soil moisture content and soil porosity, and of the soil thermodynamic parameters, such as the soil thermal conductivity, soil heat capacity, soil specific heat and soil diffusivity, by using the laboratory-measured results of the soil samples sampled from the soil profiles of 80 cm in depth in the Dunhuang Gobi Desert in northwest China on October 27, 2000. The results show that the change of soil bulk density with depth is obviously affected by the soil porosity, and it conversely correlative with the soil porosity; but the effect of the soil moisture content on it is not so obvious. The vertical change of the soil thermodynamic parameters, such as the soil thermal conductivity, soil heat capacity, soil specific heat and soil diffusivity, is related to the change of the parameters of soil structure, such as the soil bulk density and soil porosity, it is positively correlative with the soil bulk density and conversely correlative with the soil porosity; but the relationship between it and the soil moisture content is not so obvious. These reveal that the soil thermodynamic parameters are mainly affected by the soil bulk density and soil porosity. The laboratory-measured results of the soil thermodynamic parameters are close to the field observation data, and it is verified that the field observation data are reliable.