| "Thirteen-Five" is a key period to firmly establish and carry out the green development idea and promote the construction of ecological civilization.At present,due to the rapid development of urbanization and industrialization in China,it is bound to sacrifice the surrounding environment,which leads to the decline of soil fertility and pollution of soil environment.The soil quality level of the green grain production in the town scale is related to human’s life safety and health.Therefore,it is urgent to carry out soil quality investigation and evaluation.This study selected one of the most developed regions in China-the Zhulin town of green grain production in the Yangtze River delta as the research area,collected by soil survey and related data,collecting 75 soil samples of surface layer(0-20cm),analysis in lab about soil organic matter,total nitrogen,effective phosphorus,available potassium,cation exchange,pH 6 soil fertility indicators and arsenic,lead,mercury,cadmium,chromium,copper,zinc,nickel 8 kinds of environmental indicators closely related to mankind,The following studies were carried out by combining GIS technology with geostatistics and using the relevant soil quality assessment methods:(1)The quality characteristics of soil fertility analysis showed that:the average pH value of soil was 6.58,which belonged to neutral soil,and the average value of organic matter,total nitrogen and cation exchange was 28.93g kg-1,1.54g kg-1,18.63cmol kg-1,moderate content,and the average value of available K was 96.44mg kg-1,the content was low,and the average value of effective phosphorus reached 44.72mg kg-1.The results show that the effect of effective phosphorus is 44.28%there is a moderate degree of spatial correlation,which is related to structural and stochastic factors,while other fertility indicators have a strong spatial correlation,only related to structural factors;The effective variable can provide reference for the town-scale soil digital mapping,sampling design and spatial interpolation.The fuzzy comprehensive evaluation model and GIS technology combine to evaluate the soil fertility in the study area,the results show that:the overall fertility is in the middle level,the eastern fertility is higher than the west,the southern fertility reaches the level,and the soil texture,the land management mode,the fertility management and the topography of the Territory are polder.(2)The characteristics of soil environmental quality were analyzed,arsenic,mercury and chromium were 8.49,0.08,75.72 mg kg-1,which were lower than the background value of Jiangsu province.The average values of Pb,Cd,Cu,Zn and Ni were 28.57,0.2,28.91,82.47,31.93mg kg-1,higher than the background value of Jiangsu province but lower than the green standard,and the individual indexes were accumulated in some areas,but the soil environmental index of the whole area was lower than the green standard.The correlation analysis and principal component analysis obtained the industrial production is the main pollution source,followed by the transportation and the parent quality and so on the soil intrinsic attribute,the inorganic fertilizer and the pesticide massive application,the animal feed additive’s use and the domestic sewage is also one of sources.The spatial interpolation diagram shows that the more serious pollution is concentrated in the Wulian village and the Jvtou village in the western part of the town.(3)Evaluation of soil environmental quality by single factor and Nemerow pollution index model,the results show that arsenic,lead,mercury,copper and zinc can make the soil clean in a safe grade,while the pollution levels of cadmium,chromium,nickel and Nemerow pollution index(P-synthesis)are within safe range,but may be changed to the still clean grade.The potential ecological risk assessment indicates that cadmium is in the middle risk grade while others are in the slight risk grade.From the point of view of space distribution,the middle ecological risk grade is mainly distributed in the southern part of Jvtou Village,Xiangtou is less in the northwest of the village.Zhulin is a green food safety,edible agricultural product origin,the quality of agricultural products require higher,therefore,the use of green standards evaluation results.(4)Comprehensive soil fertility Index and soil Environmental index,using improved soil quality Index method(I-SQI),to ensure the accuracy of at least 8 evaluation indicators.The eastern part of Zhulin Town is more fertile than the West,and the soil comprehensive quality is lower in the area where the pollution is in the warning zone.The soil quality grade is in the medium range,there is the trend of pollution,the result compared with the comprehensive evaluation Index of Soil Fertility(IFI)and P-synthesis,the correlation is stronger,indicating that the improved soil quality index method can effectively synthesize soil fertility index and soil Environmental index,and objectively evaluate the soil quality in the town. |
PDF Full Text Request