绿洲化过程中绿洲土壤物理性质变化研究

Change of Soil Physical Properties in Process of Oasisization

绿洲化是指在一定的经济、技术条件下,为满足社会需求,把原生荒漠改造成人工绿洲的过程。利用空间代替时间的方法研究了约1 000 a来随着绿洲化进程绿洲土壤物理性质的变化过程,旨在为深入认识绿洲化过程提供依据。结果表明:①在约1 000 a的时间尺度上,随绿洲土壤开垦年限的增加,表层(0～20 cm)土壤容重与饱和水力传导度随时间显著降低,与此同时,土壤孔隙度、团聚体稳定性、粉粒含量显著增加。未开垦(0 a)和开垦约1 000 a表层土壤容重分别为1.51 g.cm-3、1.35 g.cm-3,总孔隙度为43.16%、49.27%,毛管孔隙度为38.73%、47.10%,>0.25 mm水稳性团聚体含量为24.60%、49.59%,沙粒含量为85.42%、61.56%,粘粒含量为3.93%、4.80%,土壤比表面积为128 cm2.g-1、231 cm2.g-1,土壤饱和水力传导度为0.74 cm.h-1、0.34 cm.h-1。②绿洲土壤在开垦的最初30 a间土壤饱和水力传导度、>0.25 mm干团聚体、>0.25 mm水稳性团聚体、比表面积变化相对较快,分别为0.01 cm.h-1.a-1、0.58%.a-1、0.50%.a-1、1.48 cm2.g-1.a-1。

Oasisization is the process of converting natural desert to man-made oasis for satisfying social need under a certain economy and technical condition. This paper uses the method of space substituting for time to study the changing process of physical properties of oasis soil along the oasisization in about 1000-year period. This research focuses on providing the bases to better understand the process of oasisization. The results show： ①In about 1 000-year chronological scale, the bulk density and the saturated soil hydraulic conductivity of the surface layer （0-20 cm） significantly reduced with the increase of land reclamation year, at the same time, soil porosity, stability of aggregates, silt content significantly increased. The bulk density of the uncultured （0 year） and the cultured soil （for about 1 000 years） of the surface layer （0-20 cm） is separately 1.51 g·cm^-3 and 1.35 g·cm^-3, the soil total porosity is 43.16% and 49.27%, the capillary porosity is 38.73% and 47.10%, the water-stable aggregate （〉0.25 mm） content is 24.60% and 49.59%, the soil sand content is 85.42% and 61.56%, the clay content is 3.93% and 4.80%, the specific surface area is 128 cm^2·g^-1 and 231 cm^2·g^-1, and the saturated soil hydraulic conductivity is 0. 74 cm·h^-1, 0. 34 cm· h^-1, respectively. ②In the first 30 years of the oasis reclamation, the changes are relatively fast, and the rates of the saturated soil hydraulic conductivity, dry aggregate （〉0.25 ram） content, water-stable aggregate （〉 0.25 mm） content and specific surface area were 0.01 cm h^-1·a^-1, 0.58%·a^-1, 0.50%·a^-1 and 1.48 cm^2 g·^-1·a ^-1, respectively. Keywords ： oasisization; bulk density; aggregate; clay; saturated soil hydraulic conductivity