腾格里沙漠人工植被区固沙灌木影响深层土壤水分的动态模拟研究

Simulation study on the effects of sand binding shrub on the deep soil water in a recovered area on the southeast fringe of Tengger Desert,North China

灌木是我国沙漠地区主要的优势植物类型,固沙灌木的存在有益于沙丘的固定进而有利于退化沙漠生态系统的生态恢复。基于腾格里沙漠沙坡头地区50多年的人工植被区长期观测研究,建立生态-水文模型模拟了该地区固沙灌木盖度和深层土壤水分的动态变化过程,结果表明,固沙灌木的建立改变了沙区原有的生态-水文过程,在固沙灌木建立40多年后,固沙灌木的盖度和深层土壤水分达到了新的平衡状态。灌木盖度逐渐稳定在(10±0.9)%左右,而深层土壤水分稳定在(2.58±0.2)%左右。因此,在年均降雨量为186mm的腾格里沙漠沙坡头地区,土壤水分的最大植被承载力为:灌木和生物土壤结皮的盖度分别维持在10%和60%,深层土壤水分维持在3%左右。

Shrubs were the most important dominant plants in desert areas of China.Sand binding shrubs not only are vital to stabilize sand dunes in the desert,but also are beneficial to improve ecological restoration in the desert ecosystem.Based on a long-term monitoring and study（〉 50 years） at the Shapotou Desert Research and Experimental Station,which is located on the southeast edge of the Tengger Desert,we simulated the processes of the cover of sand-binding shrub and deep soil water content using an eco-hydrological model.The model revealed that the establishment of sand-binding shrub resulted in change in the hydrological processes comparing to the mobile sand dunes.The cover of sand-binding shrub and deep soil water content had reached to a new equilibrium after 50 years the sand-binding shrub established.The balance was the cover of sand-binding shrub remained stable at（10±0.9） % and the deep soil water content remained stable at（2.58±0.2） %.In the Shapotou area of the Tengger Desert,the coverage of shrubs and biological soil crust were about 10% and 60%respectively,and the deep soil water content maintained at 3%,reflecting the maximum soil water carrying capacity of the vegetation.