2 Main Greening Tree Species Soil Physical And Chemical Properties And Soil Enzyme Activities In Shanghai

In this paper, we chose two park, Shanghai Zoo and Gongqing Forest Park as our study site, which have built over 50 years, and selected nine typical plots, including two typical urban greening species as the objects in this sutdy, Cinnamomum camphora and Metasequoia glyptostroboides, to analysis the soil quality of urban green land and the interaction between plant species and soil property. We all have 27 sampling points, through the analysis of 108 soil samples of soil physical and chemical properties, soil total nutrient and chemical metrology characteristics, soil enzyme activity size, to explore the development of more mature urban green space in different communities and study the soil mutrient levels and quality in different soil layers. Meanwhile, we also analysis the litter chemical characteristics and the activities of invertase, urease and phosphatise in different layers, which can reflect the nutrient conversion efficiency and elemental ratio between soil carbon, nitrogen and phosphorus and evaluate the quality of urban greenspace. The results show that:In longer parklands, the level of basic physical and chemical properties of soil such as organic matter, total nitrogen and total phosphorus have significantly improved and the common situation about urban green space have been a good improvement. In different plant communities, the differentiation of soil nutrient were more significant in 5-15cm that indicate the soil quality of urban green space have significantly improved in older urban green land and the coordination between soil and vegetation have also been improved. But at the same time, soil nutrient and enzyme activity have significant seasonal dynamic changes and were lowest in the summer. Besides, the problems of phosphorus-rich, nutrient availability and inharmonious nutrient proportion are also serious. So, greenland maintenance and fertilization should be controlled within a reasonable range in case of the chemical pollution and the plant limitation.In different communities, enzyme activities have closely correlation with the basic soil properties and nutrient status, and the relationship is more significantly in Cinnamomum camphora community. Meanwhile, according the analysis results about the soil nutrient status in Parks, only the soil organic matter content was significantly higher in Cinnamomum camphora community than Metasequoia but the difference of soil total nitrogen and total phosphorus content were not significant in the two communities. Invertase activity is closely related to organic matter and significant level in the two communities. At the same time, environmental factors camphor basic soil moisture-temperature conditions and other communities in soil enzyme activities were having size are more prominent role, and in Metasequoia communities, the impact of soil water and heat conditions on soil enzyme activities are not significant, indicating that under conditions of relatively sufficient nutrient conditions, soil conditions improved heat will effectively influence the activity of the soil, which also shows the influence of soil nutrient levels on soil enzyme activities of soil water to the thermal condition takes precedence.By the path analysis results, soil organic matter and the total nitrogen content are the main factors for invertase and urease, which have direct positive influence. Soil physical and chemical properties and soil enzyme activities have a close relationship. But by different factors on soil communities converting enzyme, urease, phosphatase activity coefficient of determination shows that soil properties on soil invertase strongest explanation, the decisions coefficients of invertase in two communities were 0.8173 and 0.7601. But for urease and phosphoric acid activities are lower level of explanation, which shows the basic soil invertase and soil quality and nutrient levels have closer ties, and its size can effectively reflect the activity of soil nutrient status, soil invertase can become evaluate soil fertility and soil quality enzyme targets. Soil enzyme activities to a certain extent is the reaction of soil conditions, but the kind of soil enzyme choose a more important influence on the rationality of the enzymatic soil quality evaluation.