Study On Plant Configuration Mode Of Riparian Buffer Zone In The Upper Baiyangdian

Baiyangdian is one of the most important environmental regulation functional areas in the Xiong'an New District.In recent years,the water quality of Baiyangdian has been maintained below the five categories of my country's water quality standards all year round,which is closely related to the single plant type and the low ecological function of the riparian buffer zone in the upstream of Baiyangdian.In order to select a better plant configuration model for riparian buffer zone,this paper selects three types of herbs and three types of shrubs that are common in the local area,and sets 11 configuration models of four types: single herb,single shrub,grass irrigation,and mixed grass.Runoff erosion test to study the effects of soil and water conservation and non-point source pollution control in different plant configuration modes,hoping to provide some theoretical support for the construction of local river bank buffer zone.This study mainly draws the following conclusions:(1)The stable runoff size of each vegetation type is as follows: single shrub configuration mode > single herb configuration mode> shrub-grass and mixed grass configuration mode;the stable runoff size in single vegetation configuration mode is: Cotoneaster horizontalis Decne > Forsythia suspensa(Thunb.)Vah > Lespedeza bicolor Turcz > Lolium perenne L > Cynodon dactylon(L.)Pers.In the irrigated grass configuration mode,Cynodon dactylon(L.)Pers80% + Lolium perenne L 20% + Forsythia suspensa(Thunb.)Vah has a minimum cumulative flow rate of 17.65mm/h under 30 mm/h rain;Cynodon dactylon(L.)Pers30% + Lolium perenne L70% + Lespedeza bicolor Turcz has a minimum cumulative flow rate under 30mm/h rain intensity is at least 17.5mm/h.(2)The stable sediment yield of a single vegetation configuration model is as follows: Cotoneaster horizontalis Decne > Forsythia suspensa(Thunb.)Vah > Lespedeza bicolor Turcz > Lolium perenne L > Cynodon dactylon(L.)Pers.The cumulative sediment yield of various vegetation types is as follows: single shrub> single herb> mixed grass and mixed irrigation,in which the Cynodon dactylon(L.)Pers 30% + Lolium perenne L 70% + Lespedeza bicolor Turcz configuration mode has the lowest sand production,and the sand production is 9.1g/h.(3)Cynodon dactylon(L.)Pers80% + Lolium perenne L 20% + Forsythia suspensa(Thunb.)Vah has a good purification effect on low and medium concentrations of total phosphorus,respectively 19.1% and 17.2%;Cynodon dactylon(L.)Pers 40% + Lolium perenne L 55 % + Orychophragmus violaceus(L.)O.E.Schulz 5% has the purification effect of high concentration of total phosphorus is better,at 14.4%.(4)The single shrub had the lowest reduction rate of total nitrogen,and the reduction rate of total nitrogen was about 5% in the low concentration scouring experiment.The reduction rate of total nitrogen in the irrigated grass and mixed grass configuration mode was about 15% in the low concentration scouring experiment.The ammonium nitrogen reduction rate of shrub-grass configuration mode was significantly different from that of other configuration modes(P < 0.05).In the irrigated grass configuration mode,Cynodon dactylon(L.)Pers80% + Lolium perenne L 20% + Forsythia suspensa(Thunb.)Vah in the high concentration non-point source pollutant scouring experiment has the highest removal efficiency of ammonium nitrogen in the high concentration area source pollutant scouring test,which is 11.4%.Cynodon dactylon(L.)Pers 30% + Lolium perenne L 70% + Lespedeza bicolor Turcz has the best removal effect on ammonium nitrogen in the medium and low concentration non-point source pollutant scouring experiment,and the reduction rates are 12.8% and 14.8%,respectively.(5)Comprehensive soil and water conservation and non-point source pollutant purification effects of various plant configuration modes in the riparian buffer zone,we can conclude that the comprehensive effect of herbs is: bermudagrass> ryegrass> Er Yuelan;the comprehensive effect of shrubs is: Huzhizi>Forsythia suspensa>Cotoneaster;the comprehensive effect of each plant configuration mode is: shrub grass configuration mode>mixed grass configuration mode>single herb configuration mode>single shrub configuration mode>single shrub configuration mode,among which shrub configuration mode,which of the configuration mode of Cynodon dactylon(L.)Pers80% + Lolium perenne L 20% + Forsythia suspensa(Thunb.)is optimal.