毛乌素沙地臭柏群落地下水位的变化

为了探讨毛乌素沙地臭柏群落地下水位的变化规律,在臭柏固定、半固定沙地的丘间低地设置地下水位自动记录仪,1h记录1次,连续观测1年多。结果表明:①根据地下水位的变化,把1年分成地下水缓慢上升期(A)、地下水快速变化期(B)、地下水缓慢变化期(C)3个时期;②地下水位在B期出现有规律的日变化,地下水位早晨最高,然后逐渐下降,到晚上达到最低值后,又开始上升,直到次日早晨达到最高值,完成1日的循环周期。在臭柏的非生长季节(A期、C期),地下水位的日变化规律不明显;③地下水位的日变化规律出现时的临界日平均气温为10.8℃,据此,可预测臭柏生理活动的开始与休眠,进而可指导臭柏造林实践。此外,还讨论了气温、降水及臭柏灌丛变化与地下水位的关系。

Changes of Groundwater Level in Sabina vulgaris Community in Mu Us Sandy Land

To examine the changes of groundwater level in Sabina vulgaris community in Mu Us Sandy Land,automatic-groundwater-level-meter was located on the low land of S.vulgaris patches and groundwater level was recorded continuously in a year.The results were shown as follows:(1) the whole year was divided into three phases of slow rising phase (A),fast changing phase (B) and slow changing phase (C) according to the changes of groundwater level;(2) groundwater level was the highest at dawn,going down during the day time,reaching the lowest in the evening,rising at night in the fast changing phase;and (3) the critical daily mean air tempe-rature that fast changes of groundwater level started and stopped was 10.8℃.According to this,it is possible to predict the start and the stop of physiological activities of S.vulgaris,and guide planting of S.vulgaris.Relations between groundwater level and air temperature,precipitation and changes of S.vulgaris patches were discussed.