晋西黄土区土壤剖面水分动态研究

 通过对2004年7—10月、2005年4—10月不同植被类型土壤剖面水分状况的监测,分析研究黄土区剖面土壤水分的分布特征、季节动态变化、变异特征和不同植被类型对剖面土壤水分状况的影响。结果表明:2004年剖面土壤水分呈上高下低的分布特征,2005年剖面土壤水分呈小幅度的递增变化;土壤水分在剖面上的变化包括先减少后增加“<”型和先增加后减小再增加的倒“S”型、先增后减再增再减的波浪型;在观测期,土壤剖面各土层土壤水分含量在随时间变化呈现减少趋势,与降水量关系显著;土壤水分的变异系数地表（0～20cm）最大,0～100cm土层呈减小趋势,100～200cm土层基本保持不变,将100～120cm土深作为土壤水分速变和稳定的分界限。

Dynamics of moisture of soil profile in Loess area of western Shanxi

By monitoring the soil moisture in different layers (20cm) of soil profile (0-200cm) with different vegetation cover types in loess area during 2004 (from July to October) and 2005 (from April to October), the paper focus on analyzing the distribution characteristics, the season dynamic state variety, the variation characteristic of soil moisture of soil profile and the influence of the different vegetation cover types upon the soil moisture. The result indicated that: the soil moisture increases with the soil depth decreasing in 2004, while increase is tiny in 2005. The soil moisture variety in the soil profile includes three types: the “<” type(decreasing-increasing with the increasing of the soil depth), the anti-“S” type (increasing-decreasing-increasing with the increasing of the soil depth), and the wave type (increasing-decreasing-increasing-decreasing with the increasing of the soil depth). During observation period, the soil moisture of each layer presents to reduce trend with various time, and it is closely related with rainfall. The variation coefficient of soil moisture is the biggest in the surface layer (0-20cm) in the profile, while the layer between 0-100cm presents to decreasing trend, in the 100-200cm soil layer keeping constant basically, so 100-120cm can be defined as a limited boundary between the quickly changing layer and the stable layer of soil moisture.