Research On Ecological Environment Security Of Paddy Fields In Tumen River Basin

Agriculture is the beginning of human civilization, the farmland is the earliest artificial ecosystem created by human. Rice paddies conduct as both the largest cultivated area and output which take over the largest ratio of farmland ecosystem types, it not only have the function of food production, but also has the ecological functions of reservoir for flood control, water conservation, purifying water and air, adjusting the temperature, keep soil and water, protect biodiversity conservation and so on. The Tumen River basin is located at the area in between the three country which affected by the temperate monsoon climate and coupled with intensive river distribution. It provided an excellent natural environment for an healthy production. But as the regional development and urbanization processing, paddy fields of the region ecological environment security has been sustained a certain amount of stress. Therefore, the evaluation of the paddy field ecological security through an ecological security evaluation system may do a great favor to analysis the stress factors which have a significant meaning to ecosystem health management for the future and for the sustainable development.(1) The article has synthesized ecological environment security research results both at home and abroad and draw lessons from the ecological environment safety evaluation method meanwhile combined with the characteristics of the Tumen River basin ecological environment then sorted comprehensive index eight levels to establish the Tumen River basin paddy ecological security evaluation system for dividing the ecological security of paddy field into five levels of ideal paddy ecological environment security, good condition, sensitive status and risk status and bad state in response to national and local standards to determine the indexes of evaluation criteria.(2) According to the index system, using the analytic hierarchy process (AHP) to determine weights of evaluation, using the method of weighted average of 60 monitoring for safety evaluation of the Tumen River basin. The River security comprehensive score changed between 70.00 to 70.97, while 29 ideal states accounted for 48.33% of all the monitoring stations and 31 good condition states accounted for the rest of 51.67% but no sensitive, risk status and bad state. The comprehensive score of whole river basin is 79.88 that indicate in good condition which is really close to the ideal condition. Buerhatong river basin is in the highest security level of an ideal state, LiangShui area is on a lowest security degree, but still in good condition.(3) The research handled 60 monitoring information by SPSS software to analyze related found that paddy ecological environment security and the biodiversity and soil has significant positive correlation (p<0.01), the correlation coefficient was 0.543 and 0.543 respectively, and the water quality and soil pesticide pollution index showed a negative correlation (p<0.05), the correlation coefficient of 0.270 and 0.305 respectively. Factor of the relationship between performance for the biodiversity index and multiple crop index were positively correlated (p<0.01) correlation coefficient is 0.491, the soil heavy metal pollution index and multiple crop index were positively correlated (p<0.01), the correlation coefficient of 0.432.(4) The research stand on Arc GIS platform by using Ordinary Kriging Analysis and Trend Analysis on the basin ecological environment security evaluation, the results showed that the ecological security degree present an increasing trend from the center of the basin to the both flanks in space along the northeast - southwest. From the point of trend analysis, the ecological environment security from north to south and from west to east presented an "U" type change which means the ecological security degree of the middle area of Tumen river basin is the bottom of the whole evaluation, then the northeast and the southwest and southeast stand in the best condition.The trend of ecological environment security and space distribution are basically coincidence.(5) The analysis of ecological environment security impact factor found that paddy biological diversity index is low which posed a safety hazard, and the degree of soil polluted by heavy metals and pesticides are quite low, so the water quality of paddy field has basically reached the standards for irrigation, the soil fertility can provide a good support for the growth of rice.