河北坝上半干旱／半湿润过渡带土壤水分状况研究

A STUDY ON SOIL MOISTURE CONDITION IN THE SEMIARID SUBHUMID TRANSIMON ZONE IN BASHANG REGION, HEBEI PROVINCE

本文分析了河北坝上半干旱／半湿润过渡带的阴坡华北落叶松人工林地、沙地华北落叶松人工林地、沙地沙棘林地、沙地草场、平滩草地的土壤水分物理参数、机械组成和土壤水分状况。结果表明，田间持水量、毛管持水量、最大持水量与土壤中０．０５ｍｍ～０．０１ｍｍ、０．０１ｍｍ～０．００１ｍｍ两个粒级颗粒含量呈显著正相关，而与０．５０ｍｍ～０．２５ｍｍ颗粒含量呈显著负相关。既使在干旱的年份，沙地草场、沙地沙棘林地、沙地杨树人工林地生长季初和生长季末０ｃｍ～１００ｃｍ土壤水分贮量及有效水分贮量基本平衡；而华北落叶松人工林地水分亏损较严重，但生长季末仍有２７ｍｍ左右有效水分，说明除华北落叶松人工林地外，其它植被区土壤水分状况均无明显恶化现象。由此推断，在本区人工植被建设中，采用先草本、后灌木、再乔木的人工植被建设程序从土壤水分平衡角度分析是可行的。除阴坡华北落叶松人工林地土层较薄的缘故外，其余５种植被类型的土壤水分垂直变化均有活跃层和活动层了分，只不过两个层次在土壤剖面分布深度有差异，而无类似干旱区沙地植被土壤的“死水层”，土壤水分状况均属淋溶型。

Soil moisture parameter, mechanical composition and soil moisture condition of variouslands including artificial Larix principis - rupprechtii forest land on shady slope, artificial Larix principis rupprechtii forest sandy land, Hippophae rhammoides shrub land, sandy grassland and flat grassland inthe semiarid-subhumid transition zone in the Beshang region of Hebei Province were analysed. Theresults showed that the field moisture capacity,capillary moiSture capacity and maximum moisturecapacity displayed a significant POsitive correlation with two soil particle fractions, namely 0. 01￣ 0. 05 mm and 0. 001 ￣0. 01 mm but a negative correlation with the soil Particle fraction 0. 25￣ 0. 05mm. Even in the drought years the soil water storage and the effective water storage in 0￣ 100 cm soillayer roughly kept balanced in sandy grassland, Hippophae rhammoides shrub land and sandy populusnigra forest land at the beginning and end of growth season. On the other hand, the artificial Larix principis -rupprechtii forest land exhibited a severe water deficiency, however, it still kept an effectivewater storage of 27 mm at the end of growth season. From this it was concluded that the establishmentof artificial vegetation in the region should be in the order, i. e. plant herbs first, then plant shrubsand finally plant trees. Analysed from the angle of soil moisture balance such a planting order isfeasible.