The Research Of Chongming Island Plantation Community Characters And The Physical And Chemical Qualities Of The Soils

The three islands of Chongming Island in Shanghai is one of the 21st century Shanghai important strategic space for sustainable development. In recent years, Shanghai has accelerated construction of ecological island in Chongming Island, afforestation rapidly, creating a large number of plantations, and has been the fastest growing region about forest cover in Shanghai, promoting the improvement of Chongming Island's ecological landscape.Therefore, the study of Chongming Island about the forest community structure and soil properties,analysis of application and configuration of plantation characteristics of plant communities to explore the impact of the major plant communities in the development of habitat factors, prediction of forest communities in the evolution law for the Chongming Sen Stand and and ecological reconstruction basis.The paper studied 6 kinds of plantations(Salix babylonica, Koelreuteria paniculata, Cinnamomum camphora, Ligustrum lucidum, Metasequoia glyptostroboides, Taxodium ascendens), totally 33 plant samples on each of the 8 horizontal courses identified from southern levee vertically to the northern counterpart, the paper is consisted of the research of the community characters within the samples, the testing of main physical and chemical qualities of different sections of community soils, the relativity analysis of physical and chemical factors of soil sections in different layers and causes, the general study of relativity and difference between plantation communities and soil both in horizontal and vertical spaces which refer to different communities and soil sections respectively. The detailed conclusions are as follows:1. All the plantations under investigation belong to pure forests and the community constructions is comparatively simple with tree layer, herbage but without shrub. There is a evident negative correlation(P<0.05)between the average DBH and the density of tree layer and the species of herbage is on the low side with only 20 families,40 species, while the relationship between Simpson and Shannon-Wiener index is evidently positively correlative(P<0.05).with high species diversities of herbaceous layers of Ligustrum lucidum and Salix babylonica compared with the low species diversity of Cinnamomum camphora. For horizontal courses 5 and 6, their herbaceous layers of plantation have relatively big species diversity while the course 3 has lower species diversity.2. As for the physical characters of soil, there existed some differences between the plantation and different soil sections:the bulk density of soil slightly increased with the increasing of the soil depth while the total porosity of soil and the capillary porosity of soil decreased with the depth, the mass water content of soil, the full water capacity of soil, the capillary moisture capacity and non-capillary porosity of soil didn't reveal visible rules.The ratio of capillary moisture capacity and full water capacity of Metasequoia glyptostroboides and Taxodium ascendens was high, which demonstrated the low ability of water supply of the community soils, the water supply capacity of Cinnamomum camphora and Salix babylonica was high, as they showed a low ratio, for the that of Ligustrum lucidum, it was either extremely high or extremely low.For the most communities, the ratio of capillary porosity and non-capillary porosity was between 1.5-4.1, which explained the relatively harmonious relationship among water penetrability, ventilation capacity and water holding ability of the community soils, however, for Ligustrum lucidum of course 4, the ratio of 19.8 is much higher than the that of the others which reflected the water holding ability and the ventilation capacity was awfully unharmonious.All the physical factors of the soil in the communities have shown that the broad-leaved forest is much better than coniferous forest.3. Concerned with the chemical character, there were also some differences between the plantation and different soil sections:all the soils were alkaline with ph value at 7.79-9.41, the electrical conductivity of surficial soil(0-20cm) was between 0.09-0.53mS/cm. The organic contents and the total nitrogen decreased as the soil depth increased, while the total phosphor increased firstly then decreased with the increasing of the soil depth, in terms of communities, the value relation between three variables were deciduous broad-leaved forest>deciduous coniferous forest >evergreen broadleaf forest. For different studying courses, the organic contents, the total nitrogen and the total phosphor had an initial increasing trend then decreased with a mild change for the total phosphor while quite the contrary, the electrical conductivity was high on both sides and low in between and there was no rule for the ph changes of soil.4. The relativity analysis of physical and chemical factors of different soil sections was operated and the results indicated that in soil sections of different layers, all the relation between the non-capillary porosity and total porosity, the capillary porosity and organic contents, total nitrogen and total phosphor, organic contents and total nitrogen and organic contents and total phosphor was evidently(P<0.05) or extremely evidently positively correlative(P<0.01), while the full water capacity and the capillary moisture capacity presented a extremely evidently positive correlation(P<0.01). Besides, with the increasing of soil depth, the correlation among all the physical and chemical factors of soil was obviously lower and lower.