Soil Moisture Characteristics of Different Vegetations in Northern of Ziwuling

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 forestgrasslad 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.