关键词: 生活污水尾水灌溉, 水稻, 土壤环境, 秸秆还田, 根系

Abstract: The structural analysis of urban forest communities can provide a theoretical basis for the construction and development of green cities and forest cities. The main communities of urban forests in Yangtze River Delta Region were surveyed by means of mechanical sampling and representative sampling. The latitude zonality of plant composition, community structure and community characteristics of the urban forests was analyzed. In total, 244 tree species were recorded in the surveyed plots, which belonged to 154 genera and 63 families. The distribution of species was relatively concentrated in urban forests of Yangtze River Delta Region. The top 30 species in the urban background forests and urban manmade forests accounted for 70.1% and 76.66% of total importance values, respectively. The order of species diversity of urban forests at different latitudes was 34°N <32°N <30°N <28°N, the ratio of evergreen trees to deciduous trees showed an increasing trend with decreasing latitude, and the ratio of coniferous to broadleaf species was gradually increased from west to east in the same latitude zone. The community structure of urban forests was simple. The main tree species of urban manmade forests were Platanus × acerifolia and Populus × canadensis in zones of 34°N and 32°N, while it was Cinnamomum camphora in 30°N and 28°N. The composition of tree species varied greatly among different urban background forests. However, the tendency of homogeneity was obvious among different urban manmade forests around Yangtze River Delta Region.

Key words: rice, straw returning, soil environment, sewage irrigation, root