Xuzhou City Green Space And Quality Evaluation Of Soil Carbon Storage

Urban green space is an important part of city forest ecosystem,is medium and nutrientsupply of green plants,at the same time it can filter,oxidize,adsorb,fix and purify city environment,it influences the growth of city garden plant,the quality of living environment and health ofhuman being. Thus,to develop urban green space is meaningful to promote ecological cityconstruction and ensure city ecological environment to develop sustainably. Through fieldinvestigation and laboratory analysis, we determined carbon storage of land of Xuzhou urbangreen space, and its physical and chemical properties and enzymatic activity, through principalcomponent analysis we established soil quality evaluation of the minimum data set, andcomprehensively evaluate Xuzhou urban green space, what the results show are as the following:（1） In Xuzhou,organic carbon and total reserves of the urban green space land from0to100cm is5.63×10⁸kg,inorganic carbon reserves is1.51×10⁸kg, carbon reserves is7.14×10⁸kg. InXuzhou,carbon reserves of urban green space are mainly in attached green space, public park,andgreen buffer,it occupies89.09%of carbon reserves.（2） In Xuzhou, the urban green space mainly is powder （sand） quality clay loam, loam,powder （sand） clay and powder （sandy） loam, which are good for fertilizer retention ventilatedpermeability and water retention;the average value of density of loam from0to20cm is1.25g.cm-3, only the density of green buffer is small, the differences of the density of other loamare not obvious, the average value of the density of loam from20to40cm is1.33g·cm3,thedifferences between different green space are not obvious. The density of more than60%ofurban green space is a little big in Xuzhou, which has a certain influence on the growth of urbangreen plants. The average value of cosmid content from0to20cm is30.92%, the cosmid contentof green buffer is the highest, and the cosmid content of park is the lowest, the average value ofcosmid content from20to40cm is33.12%, the difference between different green space is notobvious. The cosmid content of75%of urban green space in Xuzhou is too high or too low,which is not good for loam to exert its function. The average value field capacity from0to20cmand from20to40cm are separately20.17%and23.35%, there is no obvious difference betweendifferent green space. Loam capillary porosity and total porosity from0to20cm are separately43.33%and54.46%, there is no obvious difference between different green space, the averagevalue of noncapillary poropsity is11.21%, which of green buffer is the highest, and which ofroad green space is the lowest. The average value of capillary porosity and total porosity from20to40cm are separately40.43%and48.78%,there is no obvious difference between differentgreen space, the average value of noncapillary porosity is9%, which of the attached greenspace is the highest, and which of the road green space is the lowest. Generally, air permeabilityof50%of green space is not good, which is not good for growth of plants.（3） The content of soil available phosphorus and available potassium from0to20cm are respectively2.22mg.Kg^-1 and200.19mg.Kg^-1, there is no significant difference in differentgreen land types, the average value of hydrolyze nitrogen content is85.50mg.Kg^-1, green bufferis the highest, and which of attached green space is the lowest.In20⁴0cm soil layer, the averagevalue of available phosphorus content is1.87mg.Kg^-1, there was no significant differencebetween the different green land types, the average value of available potassium content is167.54mg.Kg^-1, the average value of hydrolyze nitrogen content is59.51mg.Kg^-1, content ofavailable potassium is highest in public park, the hydrolyzable nitrogen content is the highest ingreen buffer, the content of vailable potassium content and hydrolytic nitrogen is the lowest theroad green space. In0²0cm soil layer, the average value of total phosphorus content from0to20cm is0.94g.Kg^-1, street green belt was the highest,the attached green space is the lowest,theaverage value total nitrogen is0.96g.Kg^-1, total nitrogen content of green buffer is the highest,street green belt was the lowest, the average value of total potassium content is23.91g.Kg^-1,street green belt is the highest, nursery the is the lowest. In20⁴0cm soil layer, average contentof total phosphorus and total potassium were respectively0.88g.Kg^-1 and24.09g.Kg^-1, theaverage content of total potassium is24.09g.Kg^-1, content of the total phosphorus is highest inpublic park, street green belt is highest for the total potassium content, thecontent of the totalpotassium and total phosphorus was the lowest in the nursery, average content of total nitrogenis0.73g.Kg^-1, content of green buffer is the highest, attached green space was the lowest. Theaverage content of organic matter and cation exchange capacity from0to20cm are separately22.37g.Kg^-1 and15.5cmol （+）.Kg^-1, The average content of organic matter and cation exchangecapacity from20to40cm are separately17.84g.Kg^-1 and14.54cmol （+）.Kg^-1, the organicmatter and cation exchange capacity is the highest in the green buffer. The conclusion can beconcluded from the research data, soil organic matter, total nitrogen, available phosphorus isgenerally low and limit the garden plant growth;soil available potassium is enrichment and canmeet the demand of plant;fertilizer ability is middle;salt content does not affect to the growth ofgarden plants.（4）There is no significant differences for urease in different greenland types. The activity of peroxidase in street greenland is the highest, whereas the lowest in protection greenland. In theother sides, the phosphatase and saccharase are most activity in protection greenland, and the polyphenoloxidase is most activity in street greenland. In20-40cm soil layers, the urease has no significant differences among the greenland types except the garden greenland. For catalase, the activity is highest in affiliated greenland, while lowest in street greenland. There is no significant differences for phosphatase in different greenland types. the saccharase has no significant differencesamong the greenland types except the protection greenland. The activty of polyphenoloxidase instreet greenland is higher than other greenland types. For soil and different landcover types, the acitivity of urease, phosphatase and saccharase are highest in forest land, and the acitivity of phosphatase and saccharase are lowest in grass land. In addition, the acitivity of peroxidase and catalas e has no significant differences.The total porosity,capillary porosity, Field moisture capacity, fieldmoisture capacity and PH value has nothing effect on oil enzyme activity of urban green space,soil density obviously can block the activity of phosphatase and sucrose enzyme, non-capillaryporosity obviously can promote activity of phosphatase,catalase and sucrose enzyme,naturalwater content has an effect on the activity of peroxidase;available phosphorus obviously canblock the activity of catalase and peroxidase,available phosphorus obviously can promote theactivity of urease and peroxidase, available nitrogen and organic matter has obvious effect onUrease,phosphatase and sucrose enzyme,cation exchange capacity has obvious effect onphosphatase and sucrose enzyme;urease and peroxidase are obviously negative correlated, andare obviously positive correlated with sucrose enzyme and phosphatase, catalase is obviouslypositive correlated with phosphatase, and is obviously negative correlated with polyphenoloxidase;phosphatase is obviously correlated with sucrose enzyme. The researches show that soilphysical and chemical properties and soil enzyme activity and soil enzyme activity itself arecorrelated from different stages, and it means that soil physical and chemical properties has acertain effect on soil enzyme, thus, soil enzyme as soil quality index is feasible.（5） The eight indicators is selected as minimum data of soil quality assessment, includingsoil density,pH,available phosphorus,available potassium,hydrolytic nitrogen,cation exchangecapacity,organic matter,clay content. Soil integrated fertility index（P） from0to20cm varied inthe order of park green space （1.45）,protective green space soil （1.42）,road green space soil（1.37）,production green space soil（1.18）,roadside green space soil （1.17） and attached greenspace soil （1.07）. Soil integrated fertility from0to20cm of all the functional areas was medium（1.0<P<1.5）. Soil integrated fertility from20to40cm of protective green space, park greenspace and roadside green space were medium, other three green space soil were lower（P<1.0）.