子午岭北部不同植被类型土壤水分特征研究

Soil Moisture Characteristics of Different Vegetations in Northern of Ziwuling

研究了子午岭北部黄土区次生植被演替过程中形成的不同植被类型对土壤水分特征的影响。结果表明:土壤含水量与土壤吸力之间关系符合幂函数θ=aSb,且相关系数达极显著。参数a值也随着植被类型的不同,呈现出有规律的变化,辽东栎群落>白桦林群落>山杨林群落>狼牙刺群落>虎榛子群落>铁杆蒿群落。在同一吸力段范围内,土壤含水量由高到低的次序为:辽东栎林群落、山杨林群落、白桦林群落、虎榛子群落、狼牙刺群落、白羊草群落、铁杆蒿群落、撂荒地。在低吸力段,不同群落0～20cm土壤平均含水量的差异明显,乔木林土壤的含水量最高,灌木林高于草地土壤,撂荒地土壤最低。在20～50cm土层中,随着土壤吸力的增高,各植被类型之间土壤含水量差异逐渐缩小。在中吸力段,乔木林地0～20cm土壤含水量最高,但草地土壤含水量超过了灌木林地。20～50cm土壤含水量的变化趋势与上层土壤相似。植被类型主要是通过提高土壤有机质含量,改善土壤结构,降低土壤容重和增加土壤毛管孔隙度等土壤物理特性对土壤的蓄水和持水性能产生作用。

The soil water characteristics of different vegetations in the northern loess area of ziwuling were studied. The results show that:there was s high power function correlation between the soil moisture and the potential of soil water. The mathematical model is:θ=aS b. The value a and soil water content of different vegetations were ranged in order from higher ones to lower ones as follow:Quercus laotungensis,Betula platyphylla Suk.,Populus davidiana Dode.,Sophora viciifolia,Artemisia sacrorum, Bothriochloa ischaemum and abandoned land at a same soil potential. At the low soil potential range, the difference of 0~20 cm soil water content in vegetations was very distinctly, the soil water content of arbor forest was the highest and >shrub forest>grasslad> abandoned land; in the 20~50 cm soil, the difference of water content in vegetations was reduced with the raising of soil potential. At the middle soil potential range, the 0~20 cm soil water content in arbor forest was the best, in grassland was over shrub forest; in the 20~50 cm, the tend of soil water content was as same as in 0~20 cm soil. The types of vegetation affect soil water characteristics by increasing the soil organic matter, improving the soil construction, receding soil bulk density and enhancing the soil porosity.