| Soil is our most important natural resource and agricultural means of production, which is related to the material basis of human's survival and development. The state of soil environment directly affects the socio-economic development, ecological environment safety, food safety and human health. Along with the accelerated process of industrialization, people have to face the growing pressure from the soil environment. Soil pollution early-warning based on information technology was studied and developed, realized quick and visual evaluation, prediction and early-warning of soil pollution, and pollution information query; it provides that powerful decision-making service for soil environmental managers, so that people take pertinence measures, change degradation tendency of soil, avoid persistent pollution of soil.As modern technology of spatial data management and information analysis. Geographic information systems have special advantages in environmental risk management which is related to spatial information. Especially in recent years, the rapid development of computer technology and geographic information technologies creates good technical conditions for the establishment of early-warning system for soil pollution.In view of related soil pollution early-warning study from home and abroad and actual conditions, system requirements analysis and designing was finished. On that basis, we screened single-factor assessment model of soil, Nemoro index evaluation model, the weighted average rating model, the modified gray clustering method evaluation model, Rapant ecological risk index of risk assessment model. Hakanson potential ecological risk index model of ecological risk assessment, prediction model of soil heavy metal overtake years forecast and the heavy metal prediction and early warning model. With Microsoft Visual Studio.Net 2008 as the development platform and ArcGIS Engine 9.3 as the development component of the system, and C# as development language, the early-warming system based on.NET platform and ArcGIS Engine was designed and developed by programming these soil models.The main functions that the system desired to achieve are as follows:①Common functions of GIS, including basic functions of map operations (enlargement, reduction, roaming, full map display, forward, rewind, scale, etc.). Hawkeye navigation, layer control, map browsing, maps plate, right shortcuts, status bar display, etc.;②Map editing functions;③Soil query functions (spatial query, attribute query, through the graphical relationship between the spatial location (intersection, with leave, including, border contacts,etc.) to check and the query by attribute table);④Evaluation of soil pollution (soil single-factor evaluation, Nemoro index rating, the weighted average rating, the modified gray cluster method);⑤Soil ecological risk assessment (Rapant ecological risk index of ecological risk assessment of heavy metals, Hakanson potential ecological risk Index of ecological risk assessment of heavy metals);⑥Heavy metal content of soil life prediction;⑦prediction and early warning of heavy metal content accumulation.Finally, taking example of Lishui, the national ecological demonstration counties County, Nanjing City, Jiangsu Province, we used the system for practical application. The results of application based on the system, revealed general soil heavy was good, however, the some heavy metal, for example Hg, Pb is serious in some monitoring point, and has a great ecological risk, the predicted results suggested that the people should pay attention to this situation. The results of system test showed that the system worked well, as well as stably, system interface was friendly, the results were visual and imaged, and we achieved the desired design goals. This study was finished for the first time at home;it provided that powerful decision-making information service for soil environmental managers, and was important application value and practical significance. |
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