Study On The Water-Soil Environment Characteristics And Evaluation On The Ecological Adaptability Of The Cultivated Tree Species In Karamay Agricultural Development Region

Through comparison of groundwater level and the soil physic-chemistry properties in Karamay Agricultural Development Region before and after land exploitation,the water-soil environment characteristics are explored;Through soil section investigation and soil sampling determination,principal component analysis(PCA)was employed to analyze the dominating factors of dividing site types of forestation land and then divided forestation land into different site types by three -dimensional PCA ordination and also evaluated soil quality of forestation land by establishing integrated soil quality model; Through typical sampling plots where growing indexes and chlorophyll fluorescence parameters which were initial fluorescence(Fo),maximal fluorescence(Fm),maximal efficiency of primary conversion of light energy of PSâ…¡(Fv/Fm)and maximal potential of primary conversion of light energy of PSâ…¡(Fv/Fo) were determined of three groups of tree species based on cultivation purposes(ecological windbreak tree species,ecological economic tree species and ornamental tree species),adaptability of diffrent tree species were evaluated and systematically integrative multipurpose and multi-index evaluation systerm were established and physiological adaptability was discussed.The main results showed:The water-soil environment characteristics in this region had changed evidently after land exploitation, featuring groundwater level rising accompanied by groundwater salt concentration decreasing as well as soil salinity concentration decreasing accompanied by soil fertility decreasing.Groundwater level in irrigation area indicated gradually rising trend that had obvious annual and seasonal variation law while groundwater level in wasteland and transition zone indicated slowly rising trend;Although groundwater salt concentration has been diluted to some degree,it still belongs to high range;The soil salinity concentration of exploited land had decreased evidently because of eluviations by irrigation water,but the soil fertility also had decreased evidently.Soil total salinity concentration,C1^-,K⁺+Na^-,Mg²⁺,SO₄²⁺,Ca²⁺,CO₃^2-,pH value,organic fraction, instant nitrogen and degree of soil compactness were the dominating factors of dividing site types of forestation land in development region;Eight site types were classified by PCA ordination.The integrated soil quality index of eight site types ranged from 0.279～0.494 and from general review soil quality of forestation land was situated low level and salinization,low nutrient and high degree of soil compactness were the main limited factors.The adptability evaluation results showed that Tianyan Yang had higher increment of tree height and diameter at breast height than Populus alba var.pyramidalis Bge.and Populus pioneer Jabl.,but it liable to breaking by wind.Three species of Californium L.performed badly judged from poor vigor of tree and low survive rate due to unsuitable soil conditions.The cold resistance of Robinia salsul L.,Sophora japonica L. and Catalpa ovata G.Don were weak.Some ornamental species such as Ginkgo biloba L.and Toona sinensis(A.Juss.)Roem.basically could not adapt to the environmental and site conditions in development region,which should be limited further introduction or gave up.Indigenous pecies such as Populus euphratica Oliv.and Elaeagnus angustifdia L.and some native shrub presented strong ecological adaptability.In addition,most of economic species in this area were in initial phase of fruit,not only high vigor of tree but high fruiting rate.The characteristics of chlorophyll fluorescence parameters indicated the value of Fv/Fm of most ecological windbreak tree species decreased at am.with diurnal variation of solar radiation,air temperature and air relative humidity and increased at pm..The value of Fv/Fm of Fraxinus rhynchopylla Hance, Catalpa ovata G.Don,Ulmus densa Litv.and Populus laurifolia Ledeb.retained on a lower level during the whole diurnal variation process but that of Populus euphratica Oliv.,Elaeagnus angustifolia L., Hippophae rhamnoides subsp,sinensis Rousi,Salix matsudana var.matsudana f.umbraculifera Rehd.and so on kept on a higher level and photosynthetic "rist" occurred to Populus euphratica Oliv.,Elaeagnus angustifolia L.and Hippophae rhamnoides subsp,sinensis Rousi at 10:00 oclock.Except T1/2 of Populus euphratica Oliv.Elaeagnus angustifolia L.,and Salix matsudana var.matsudana f.umbraculifera and so on did not evidently varied at p.m.compared with the same value at a.m.,T1/2 of the other tree species decreased to some certain extent.From general review of Fo,Fm,Fv/Fm and Fv/Fo at three times during a day and T1/2 of windbreak shrub,economic and ornamental species,except Lycium barbarum L.,Prunus tomentosa Thunb.and Rosa laxa Retz.and so on,although most tree species were light inhibited to some extent due to high light,high temperature and low humidity,they could recover to normal level toward evening.