The Study On Water Using Situation Of Poplar Based On The Stable Isotope In Otinday Sandland

In recent years,human activities have caused the deterioration of the global ecological environment.The problem of water use in plants in arid and semi-arid regions has been particularly acute.In order to improve the situation of desertification in Otinday Sandland and rebuild people's green homeland.Based on stable carbon,hydrogen and oxygen isotope tracer techniques,combined with quantitative equations,multi-source linear mixed models,and thermal diffusion methods.This paper analyzed the water use efficiency,the source of water absorption and the canopy water consumption of poplars,and then discussed the water use strategies of poplars using poplars in their natural state as research materials in Otinday Sandland.It provides a theoretical basis for the optimal allocation of water resources in the region,selection of dominant tree species,restoration of the local ecological environment and sustainable use.The main results are as follows:?1?The?¹³C values of the leaves in the region ranged from-23.10‰to-28.46,the average value was-25.28‰,which had no strong correlation with temperature,but had a negative correlation with precipitation.The range of?D and?¹⁸O values of branch water was wide,which is characterized by low trend in the rainy season and high trend in the dry season.It has no correlation with temperature and precipitation,but has strong correlation with hydrogen and oxygen isotopes in precipitation.?2?The water use efficiency of poplar in 2016,2017 was calculated by using the quantitative equation,and it was found that poplar is a species with high water use efficiency.The results of WUE in these two years showed that poplar was under more water stress in 2017.In order to deal with water deficit,poplar increased water use efficiency.?3?Based on the direct correlation method and multi-source linear mixed model,we analyzed the water sources of poplars in different months.The results showed that soil water of 0-50cm and groundwater is the major sources of water absorption.When precipitation is insufficient,poplars use deep soil water or groundwater.When precipitation is over,poplars use the more easily absorbable precipitation water source to spend the growing period by transforming different water-absorbing layers.?4?Compared the local precipitation with the canopy water consumption which calculated by thermal diffusion method,this paper quantitative analyzed the water balance monthly;and then combined with the water use efficiency and the source of water absorption,the water use strategy of poplar was discussed.The strong root system,high water use efficiency and adjustable water use mechanism make poplar to maximize the use of limited water resources,which is also the main reason for its survival in arid and semi-arid areas.