Difference And Hysteretic Effect Of Ring Growth Of P.euphratica To Groundwater Change In The Lower Reaches Of Tarim River

In the lower reaches of Tarim River as the research target,arid desert populus euphratica as the research object.By the method of mathematical statistics,comparative analysis of different cross section of the radial growth of populus euphratica and the relationship between the groundwater depth,quantitative study of populus euphratica growth reasonable levels.On this basis,using hysteresis model,calculate the hysteresis effect between groundwater on populus euphratica growth,and provide a theoretical basis for the healthy growth and lower Tarim River Populus recovery.The main conclusions are as follow:(1)The study found that the radial Populus in the lower reaches of Tarim River in four sections:growth in 1980-2010 years,the average annual growth of Yingsu section is 0.219 mm,Kaerdayi section average annual growth was 0.1664 mm,Alagan section average annual growth was 0.1864 mm,Yiganbujima section of the year the average growth of value is 0.0994 mm.In 1980-2010 years,except the Yingsu section,other section of radial growth of Populus euphratica volume changes were not obvious,the Kaerdayi section is the least fluctuation.During 1980-1998,Yingsu section and Kaerdayi section Populus tree ring index showed a overall downward trend,Alagan and Yiganbujima section is little overall change.(2)The lower reaches of the Tarim River four sections for anomaly processing,draw the variation of annual tree rings in radial growth amount.Yingsu section in 1980-1996 years,the overall value is lower than the average,in 1996-2010 years(except 2010)higher than the overall average value of its value;Kaerdayi section in 1980-1987(except for 1980 and 1986)and 1997-2010(except 2006-2007 and 2009-2010)is higher than the average,lower than the average in 1988-1996 years;Alagan in section 1980-1985 and 2001-2007 is higher than the average value in 1986-2000 and 2008-2010 is lower than the average;Yiganbujima in 1980-1985(in 1983)and 2004-2010(except 2010)is higher than the average,lower than the average 1986-2003 years(except 1990).(3)The mutation analysis of the growth of Pop ulus euphratica in the four sections of the lower reaches of the Tarim River shows that the following conclusions can be drawn:Yingsu mutation in Pop ulus euphratica occurred in 1997 and showed a significant trend after 1998.The mutation of Kaerdayi section occurred in 1985,1997 and 2008,and decreased significantly from 1988 to 1995.Alagan mutations occurred in 1983,2001 and 2010,showed a significant downward trend from 1984 to 2001Yiganbujima mutations occurred in 1981 and 2005,showed a significant downward trend from 1989 to 2002.(4)Populus radial growth with the decline in the four sections of the groundwater level,the sensitivity was first increased,then decreased.groundwater level corresponding to the maximum sensitivity are:Yinsu section 5.38m,Kaerdayi section 6.66m,Alagan section 7.81m,Yiganbujima section 7.84m.Description Populus radial growth of four sections differ groundwater level changes in response to the sensitivity of Populus growth of sensitive groundwater level range between 5.4-7.8 m.(5)The lower reaches of Tarim River groundwater will have a lag effect on the current year and the next year the growth of Populus euphratica.In different sections,the lag effect of duration is different:Yingsu section No.1 and No.2 well for 2 years,No.3 well for 1 years;Kaerdayi section three monitoring wells were 2 years;Alagan section No.l and No.2 wells for 2 years,No.3 well for 1 years;Yiganbujima section No.1 and No.3 wells for 1 years,No.2 well for 2 years.