古尔班通古特沙漠边缘春秋季沙丘水分状况初步研究

古尔班通古特沙漠边缘植被破坏严重,沙丘活化明显,是新疆干旱区植被恢复的重点地区之一,当地降水稀少,其沙丘的水分状况便成为植被生存和恢复过程的关键条件,为掌握古尔班通古特沙漠边缘流动沙丘和固定沙丘不同部位的水分状况,从2003年3月到10月植物生长期内利用中子仪进行连续监测的结果表明:沙丘含水量月变化与月降水量分布相一致;流动沙丘0-30cm的含水量低于固定沙丘,而其它各层都高于固定沙丘;流动沙丘含水量从上部到下部依次升高,而固定沙丘则并无此规律;流动沙丘中部和下部稳定湿沙层处在距沙丘表面60cm以下,且厚度超过100cm,固定沙丘稳定湿沙层只存在于沙丘中部距沙丘表面60~150cm深度范围内,其厚度不超过100cm。

The Research on Soil Moisture of Shrifting Dune and Fixed Dune at Fringe of Guibantonggut Desert

The exploitation of resources and an increase population at fringe land of Gurbantonggut Desert in Junggar Basin has caused environmental disturbance to the fragile desert ecosystem. The fixed and semi-fixed dunes are becomingactive rapidly。According to natural conditions of Gurbantonggut Desert, many measures must be taken to restore and reconstruct the natural vegetation, maintain the original, safe and stable desert ecosystem. The fringe of the desert is a important zone for vegetation restoration, The key for vegetation restoration is to know the soil moisture of dune. With the field calibration by neutron, the soil moisture change in different terrain parts which contain the crest, slope, and the foot of the shrifting dune and fixed dune at fringe of Guibantonggut Desert are measured continuously. The records show that the monthly moisture variation of dune is related to the precipitation; soil moisture of shifting dune in upper layer is lower than fixed dune's, while the other layers' is reverse; the soil moisture of shifting dune is increase from the foot of dune to the crest, which is not obvious in fixed dune; the steady humid sandy layer is at the depth of60㎝ under the surface and the thickness is more than100㎝ atslope and the foot of the shrifting dune; the stablehumid sandy layer is at the depth from 60㎝to 150㎝and the thickness is lessthan 100㎝. In order to restore and stabilize the ecosystem that has been damaged by human activity, some measures should be taken to choose appropriate plant species and densities regarded to soil water availability. This study has shown that understanding soil moisture patterns in shrifting dune and fixed dune is essential for delivering successful revegetation and rehabilitation strategies. These will provide scientific information and instructions for restoring and reconstructing the ecosystem that has been damaged by human activity.