Research Of Soil Harmful Animals In Outring Green In Minhang District, Shanghai

Soil fauna is an importat composition urban ecological system, and soil harmful animals plays an important role in the direction of health and balance of urban ecosystem. The study of soil pests is ripe in agriculture and forestry ecosystems, but it is far less involved in urban ecosystem. Because of the speciality of urban ecosystem, we analyze the occurrence of soil pests and their relationship with the physical and chemical factors combined with aboveground insects and based on the results of animal studies.The green belts at Shanghai Outer Ring expressway in Minhang District is the research object. We chose two sites which located in the opposite side of the out ring expressway from November 2008 to April 2009, with three different types of greens vegetations. We investigated the soil animals'communities of greens, soil temperature, soil moisture, soil nutrients and other environmental factors and made a comprehensive analysis of these factors. In order to study the relationship between the environmental factors and the associated biological communities, we did the former wok in the region to understand the health status of the soil environment. The main conclusions of the study are as follows:1,The soil animal community structure and seasonal change in different plots.Acarina is the dominant group in litter layer; however Nematoda and Acarina are the dominant group in soil layer. The total density of soil fauna is 3.35×105 ind.·m-2, the seasonal change of soil fauna is as follows spring> summer> winter> autumn. Changes of community diversity in four seasons are as follows:summer> autumn> spring> winter.The number and density of soil fauna were different in 6 plots. II-B shows the highest group number and density. Similarly, the difference of the composition of soil fauna is significant, but Nematoda and Acarina are dominant groups are in each plots. The number and density of soil fauna in the outer green belt were not very different from the inner green belt and the inner one was higher than the outer one.2,Community structure of soil fauna and soil harmful fauna in different afforesting typesThe change of group numbers of soil fauna in different afforesting types was the same as soil harmful fauna, which showed that the result of deciduous broad-leaved forest was higher than deciduous coniferous forest and evergreen broad-leaved forest. In regard to density, deciduous forest was the highest in both soil fauna and soil harmful fauna. And both of them showed the highest density respectively in deciduous coniferous forest and deciduous broad-leaved forest. The change of soil fauna and soil harmful fauna in evergreen broad-leaved forest was the same as deciduous coniferous forest.3,Community structure of soil fauna and soil harmful fauna in different types of soil background.The higest number of groups of soil fauna and soil harmful fauna were respectively showed in external soil and farmland soil. Farmland was highest in both soil fauna and soil harmful fauna. The proportion of dominant groups was higer in external soil than farmland soil.The seasonal variation of diversity index was obvious in different types of soil background. Spring was the highest season in diversity index of soil fauna, while summer was the highest of soil fauna in farmland soil and soil harmful fauna in external soil. Winter was the lowest season in others except soil harmful fauna in farmlandThe total density of soil animals in litter layer was not significantly related with pH, organic matter, total nitrogen, total phosphorus (p> 0.05), while in soil layer the density showed a significant positive correlation with organic matter(r=0.401, p<0.01), and no significant correlation with pH, organic matter and total phosphorus had (p>0.05). Most pest species associated with nitrogen and phosphorus contents.4,The relationship between soil harmful animals and aboveground insects in different afforesting types and different types of soil backgroundIn regard to the result of comparison of soil insect and aboveground insect, there was a total of 12 groups showed in both of them. Seven groups of pests were collected only in soil, which were Persimmon Scales, Scolytidae, Notodontidae larvae, Oedemeridae, Miridae, Anthomyiidae and Tettigonioidea. Analysis of changes in different seasons and different plots of Scarabaeidae,Noctuidae and Pyralididae showed that the proportion of soil harmful animals in insects was higher in soil than aboveground.