塔里木河下游胡杨对水分条件变化的响应

Analysis on the Respond of the Tree-rings of Populus euphratica to the Change of Moisture Conditions in the Lower Reaches of the Tarim River

通过对塔里木河下游应急输水河畔胡杨样枝的年轮分析,结果表明:第3次应急输水后,喀尔达依断面胡杨的横向响应范围达到离河1 000 m;应急输水后不同断面、不同离河距离,地下水埋深梯度、过水时间梯度随着离河道和大西海子水库距离增加,胡杨生长量减少;输水量大的年份胡杨生长量明显大于输水量少的年份,在相同输水量和输水时间前提下,春秋季持续输水对胡杨生长恢复效果要优于夏秋季输水;在持续输水后,胡杨生长量增长幅度减小,其大小逐步趋于近似。

After the Daxihaizi Reservoir was built in 1972, the stream of the mainstream in the lower reaches of the Tarim River was cut off. In order to regenerate the vegetations along the watercourse of the lower reaches of the Tarim River, a project of urgently transfusing stream water to the lower reaches of the Tarim River has been started since 2000. Since then many scientists begin to investigate and analyze the ecological response including the physiological response and ecological response of the vegetations in the lower reaches of the Tarim River. In this paper, the tree-rings of Populus euphratica in the lower reaches of the Tarim River after implementing the project of urgently transfusing stream water are sampled and analyzed. The results reveal that the zone width of the physiological and ecological response of Populus euphratica along the Karday section, perpendicular to the watercourse of the Tarim River, was up to 1 000 m in the lower reaches of the Tarim River after implementing the third time of urgently transfusing stream water; the growth of Populus euphratica is reduced and the groundwater depth is increased with the increase of distance away from the watercourse of the Tarim River and the Daxihaizi Reservoir after urgently transfusing stream water; the growth of Populus euphratica is increased and the groundwater depth is decreased with the increase of transfused water volume and of the time; under the same transfused water volume and of the time, growth of Populus euphratica is higher in spring than that in summer.