荒漠人工固沙植被区浅层土壤水分动态的时间稳定性特征

Temporal Stability of Surface Soil Moisture in Artificially Revegetated Desert Area

试验在地表由生物土壤结皮覆被的荒漠人工固沙植被区进行,通过对0.45 hm2试验样地浅层(0—15 cm,0—30 cm)土壤水分连续动态(2005年4—10月)测定,基于经典时间稳定性理论分析,来揭示荒漠人工固沙植被区浅层土壤水分动态的时间稳定性特征。结果表明,无论在干旱或湿润条件下,浅层土壤水分都具有明显的时间稳定性特征,并且在土壤剖面30 cm深度表现得比剖面深度15 cm更为显著;在干旱条件下,两种土壤剖面深度的土壤水分时间稳定性特征均比湿润条件下显著。根据研究结果,初步确定了试验样地平均土壤水分含量的代表性测点。

The aim of this paper is to discuss the applicability of temporal stability theory in soil moisture of artificially revegetated desert area. Here we analyzed the temporal stability of soil moisture content in an area of 0.45 hm^2 located in the artificially revegetated desert area where has been fixed for fifty years and the bio-crust covered the whole surface. The data from a network consisting of 60 soil moisture measuring points over a period of 7 months （from April to October 2005） were used. At each point, soil moisture was measured at the different time using time domain reflectometry （TDR） in the depths of 15 cm and 30 cm. The results clearly showed which point was the mean representative soil moisture point. The temporal stability was high under even the most extreme situations. This pattern was more obvious in the depth of 30 cm than in the depth of 15 cm and the temporal stability was always higher when the soil was dry than when the water content was high.