Study On The Function Of Water Conservation Of Oak Forest Of Purple Mountain

In this paper, the hydrological characteristics of forest crown, litter and its soil of Oak forest of Purple mountain were examined and studied with open field investigation and experimental localization observation method. The results show that:(1)In observation of 51 times precipitation, total precipitation was 879.5mm, canopy interception, stemflow, throughfall of the forest were 226.03mm,35.44mm,618.03mm, which account for 25.07%,4.03%, and 70.27% of the total precipitation, respectively. With the increase of precipitation, the canopy interception, stemflow, throughfall and throughfall rate increases gradually, while the ratio of canopy interception decreases in a decreasing speed, the ratio of stemflow increases when precipitation is less than 30mm but decreases after beyond that.(2)The extant biomass of Oak forest was 14.13 t/hm2. the litter rapid absorbed water when soaked in water totally, The maximum water absorption rate appeared in 0-0.5h, and then gradually decreased, at last saturated in the 18h, Maximum water holding rate was 310.12%. Under natural conditions, Maximum water holding rate of litter was 100%, which is comparatively different with the immersion experiment.(3)Soil moisture content were about 10% to 20%, The highest soil water content appeared in April, followed by July, September, and the soil water content achieved minimum value in November and December by the impact of precipitation and temperature. Maximum soil water content also appeared in the April, the major factors were the higher precipitation and higher soil moisture. Minimum appeared in July, August and December, which were affected by high temperature and short of precipitation, and the surface layer soil were affected more obvious by the high temperature.(4) After precipitation, the increment of soil moisture were positive correlation with precipitation, there was a good correlation between surface soil moisture increment and precipitation, but the subsoil moisture increment were lag, therefore, the correlation is very poor. Loss of surface soil moisture were affected by air temperature, when soil moisture is similar in the early, the higher the atmospheric temperature, the greater the loss of soil moisture.