Effect Of Vegetation Allocation Model Of The Unit Attached Green Space On Microclimate Along The Yellow River Urban Belt In Ningxia

Urban forest is an important way to solve the contradiction between urban development and environmental protection and the green space of the unit’s affiliated is an important part of the urban forest ecosystem,and its unique ecological function and social function is played in improving the small climate.This study takes the six unit affiliated green spaces of Huaiyuan campus of Ningxia University,Ningxia Hospital in Yinchuan,Litong District Government,wetland protection and management center,Mingzhu Park Management Office in Wuzhong and Zhongwei campus of Ningxia University in Zhongwei along the Yellow River urban belt in Ningxia as the research objects,the seven meteorological factor indexes of temperature,relative humidity,solar radiation,wind speed,PM2.5,PM10 and negative oxygen ion,the differences of 11,8 and 17 typical vegetation allocation modes in four seasons microclimate regulation ability and air quality improvement ability were analyzed in Yinchuan,Wuzhong and Zhongwei city respectively.The results show that:Different plant allocation patterns in the unit affiliated green space of Yinchuan City have a certain regulatory effect on the microclimate in the four seasons,among them,The Greenland of YD5 Treeshrub-grass(Salix matsudana Koid-Euonymus japonicus Thunb-Festuca elata Keng ex E.Alexeev)and YD6 Tree-shrub-grass(Fraxinus chinensis Roxb-Rosa ssp-grassland)types and YD7 coniferous forest land(Juniperus formosana Hayata-PiceacrassifoliaKom-Pinus sylvestris var.mongolica Litv)have the best effects on temperature in spring,summer and autumn,humidifying and wind proofing in four seasons.Compared with the control,The average temperature drop is 1.08℃,the humidity is increased by 6.21%,and the wind speed is reduced by 0.47 m/s;YD5 Tree-shrub-grass(Salix matsudana Koidz-Euonymus japonicus Thunb-Festuca elata Keng ex E.Alexeev)has the best regulation effect on dust prevention and dust retention,reducing particle concentration by an average of 5.20 μg/cm3,YD4 Tree-grass(Populus Xhopeiensis Hu&Chow-Festuca elata Keng ex E.Alexeev)and YD5 Tree-shrub-grass(Salix matsudana Koidz-Euonymus japonicus Thunb-Festuca elata Keng ex E.Alexeev)types have the greatest effect on shading and cleaning.which reduces the solar radiation by 249.12 w/m2,and increase the concentration of negative oxygen-ions by 70.87/cm3.YD1 Tree-shrub(Fraxinus-Juniperus)green space,low canopy density near the paved land with large pedestrian flow has no obvious regulation effect on each microclimate index.Different plant allocation patterns in the unit affiliated green space of Wuzhong City have a certain regulatory effect on the microclimate in the four seasons.Among them,The greenland of YD5 Treeshrub-grass(Robinia pseudoacacia L.-Amorpha fruticosa L.-Festuca elata Keng ex E.Alexeev)type with deciduous broad-leaved trees and YD6 Tree-shrub-grass(Fraxinus chinensis Roxb-Forsythia suspensa-Festuca elata Keng ex E.Alexeev)type with deciduous trees and mixed needles and broad leaves has the best effect on temperature in spring,summer and autumn and humidification,wind prevention,dust prevention and dust retention and cleaning in four seasons.Compared with the blank control,The average temperature drop is 0.3℃,humidification is 5.87%,wind speed is reduced by 0.10 m/s,and particle concentration is alleviated by 3.34μg/cm3,increase the concentration of negative oxygen-ions by 73.61/cm3;YD6 Tree-shrub-grass(Fraxinus chinensis Roxb-Forsythia suspensaFestuca elata Keng ex E.Alexeev)and YD1 Tree-shrub-grass(Robinia pseudoacacia L-Carica Papaya L-Festuca elata Keng ex E.Alexeev)types have the greatest shading effect,which reduces the solar radiation by 112.62 w/m2.YD3 Tree-shrub-grass(Albizia julibrissin Durazz.-Euonymus japonicus Thunb-Festuca elata Keng ex E.Alexeev)green space with broad-leaved trees and low canopy density showed poor regulation effect on seven microclimate indexes.Different plant allocation patterns in the unit affiliated green space of Zhongwei City have a certain regulatory effect on the microclimate in the four seasons,among them,The Greenland of YD1 Treeshrub-grass(Ulmus pumila L-Juniperus procumbens(Endlicher)Siebold ex Miquel-Festuca elata Keng ex E.Alexeev)type has the best effect on temperature in spring,summer and autumn,shading,dust prevention and dust retention and cleaning in four seasons.It reduces the temperature by 1.14℃,reduces the solar radiation by 270.74 w/m2 and reduces the concentration of particulate matter by 7.92μg/cm3,and increase the concentration of negative oxygen-ions by 296.52/cm3;YD1 tree-shrub-grass(Ulmus pumila L-Juniperus procumbens(Endlicher)Siebold ex Miquel-Festuca elata Keng ex E.Alexeev)and YD4 arbor-shrub-grass Ulmus pumila L-Lonicera japonica Thunb-grassland)types have strong humidification and wind protection ability,with an average increase of humidity of 2.69%and a decrease of wind speed of 0.17 m/s.YD 13 grassland has the worst regulation effect on microclimate.Through the principal component analysis and comprehensive evaluation of the climate indicators of the affiliated green space in Yinchuan,Wuzhong and Zhongwei,it is found that the compound mode of arbor,shrub and grass has the best effect on regulating microclimate of unit affiliated green space,which the ecological effect of YD5 tree-shrub-grass type green space in Yinchuan is the best,in which the arbor planting is mainly Salix matsudana Koidz.and PiceacrassifoliaKom.,with reasonable dense planting of Euonymus japonicus Thunb,Lonicera japonica Thunb and Festuca elata Keng ex E.Alexeev;the ecological effect of YD6 arbor-shrub-grass green space in Wuzhong City is the best,in which the arbor planting is mainly Robinia pseudoacacia L,Fraxinus chinensis Roxb,with reasonable dense planting of shrubs such as Amorpha fruticosa L.,Tamarix chinensis Lour.,Forsythia suspensa and herbs such as Festuca elata Keng ex E.Alexeev;the ecological effect of YD1 arbor-shrub-grass green space in Zhongwei city is the best,in which the arbor planting is mainly Armeniaca vulgaris Lam.,Prunus salicina Lindl.,Acer pictum subsp.mono(Maxim.)H.Ohashi with reasonable dense planting of Sorbaria sorbifolia(L.)A.Br.and grassland.