The Relationship Between Different Age Populus Euphratica's Radial Growth And Groundwater Depth

Populus euphratica is the main building group plant of the Tarim River basin's desert riparian forest, and groundwater is the main limiting factor of it, the relationship between them has been paid much attention. Aim at previous research ignored the response between groundwater and populus euphratica is different probably, because different age populus euphratica's water requirements is defferent, this paper selected the lower reaches of Tarim River as the survey region, populus euphratica's radial increment as research object, discuss the response relation of populus euphratica of ecological water conveyance, and analysis the stress water level and the limit water level. The results of this study can provide reference for plan establishment of populus euphratica's protection and rational utilization of water resources. Recording this study, we get some main conclusions as follows:Populus euphratica radial growth shows an obvious V-shaped reversal before and after the ecological water conveyance, the ecological water conveyance promoted the growth of populus euphratica. In the process of ecological water conveyance, the relationship of populus euphratica radial growth and water carrying amount is significant, and the response is long-term and sustainable. The relationship between groundwater recharge and radial growth is not significant in the year, and the radial growth has a significant regression relationship with the groundwater recharge mean of last 2 years, so when we recovering the populus euphratica forest of the Tarim River lower reaches, we should ensure the average groundwater recharge amount is large at least 2 years.There is a close relationship between the populus euphratica radial growth and groundwater depth, the radial increment shows a "falling-up-falling" trend with groundwater depth falling, but shows a downward trend integrally. The different age populus euphratica's radial increment significant correlation groundwater depth, and they obey different regression functions.The different age forests have different stress and limit water level, the stress and limit water level of mid-maturation forest are 3.42 m and 6.70 m, and the near-mature forest are 3.37 m and 7.08 m. In order to make all age populus euphratica forest growing well, when we recovering different age populus euphratica forest must be take different measures, groundwater buried depth after the ecological water conveyance should maintaining at about 3 m.