The Quality Of Farmland Soil In Xiaoyi Mining Area And Potential Ecological Risk Assessment

Soil is an important part of the earth’s ecosystems are inseparable,is what we are on the basis of all activities of agricultural production.While providing mechanical support to the crops growing on it,it also provides various fertility factors such as water,fertilizer,gas and heat.However,due to the past for a long time use of high input,high consumption and low efficiency of extensive pattern of economic development to produce large amounts of waste makes a lot of soil have been seriously polluted.Taking farmland soil of xiaoyi mining area as the research object,the soil nutrient data and heavy metal content data of each sampling point in the research area were obtained through the collection of outdoor soil samples and the relevant indoor research and analysis.After a series of data processing and image drawing by Excel2010,SPSS21.0 and Arcgis,the content level and differentiation rules of soil fertility indexes and heavy metal elements required in the study area were clarified.On this basis,soil nutrient grading and soil environmental quality assessment were also conducted for farmland and soil in the study area.The main conclusions are as follows:(1)The soil pH in the study area is at 8.00 to 8.69,and the soil is slightly alkaline.The pH order of the four towns in the study area is town of gaoyang>town of dui= town of wutong>town of yangquan qu.The high and low order of organic matter content was town of yangquan qu>town of wutong>town of gaoyang>town of dui.The order of alkali-nitrogen content was town of yangquan qu>town of gaoyang>town of dui>town of wutong.The order of the effective phosphorus content was dui town>gaoyang town>yangquan qu town>wutong town.Rapidly-available potassium content of high and low order was yangquan qu town>dui town>wutong town>gaoyang town.The concentration of organic and alkaline nitrogen in the soil in the study area is a very low level,and the concentration of efficient phosphorus and instant potassium is in the rich level.It reflects in the research area of farmland nutrients in the soil structure is not reasonable.(2)According to the calculation and rating of soil comprehensive nutrition index of farmland soil in the research area,the soil nutrient classification in various towns is classified as yangquan qu town(medium)>dui town(low grade)>gaoYang town(very low)= wutung town(very low).It is clear that that quality of farmland in the mine area of xiayi city is worrying(3)The content of organic matter in the study area is larger in western mountainous area than eastern plain area than middle hilly tundra area.In general,the distribution of alkali nitrogen content in western mountainous area is larger than middle hilly tundra area and greater than eastern plain area.The content of available phosphorus is that the middle hilly tundra area is larger than the western mountainous area and greater than the eastern plain area.The content distribution of available potassium is generally that the western mountainous area is larger than the middle hilly tundra area and the eastern plain area.(4)The correlation analysis of soil fertility indexes in the study area shows that pH is negatively correlated with alkaline nitrogen,organic matter is positively correlated with alkaline nitrogen,effective phosphorus is positively correlated with rapidly available potassium,and other indicators are not significantly correlated with each other.(5)Heavy metal elements As,Hg,Cd,Cr,Cu,Zn,Pb,Ni in the study area exceeded the soil environmental background value of luliang to varying degrees,and they all accumulated to a certain extent in the soil.However,the content of each heavy metal element did not exceed the risk screening value(basic project)of soil pollution in agricultural land in the "soil environmental quality control standard for soil pollution risk of agricultural land(trial)"(GB15618-2018).In other words,the farmland soil in the study area has been contaminated by the eight heavy metals,all of which are within the tolerable range(6)The content of heavy metal As was distributed in the middle hilly tundra of>in the western mountainous area of>in the eastern plain.The distribution pattern of Hg content is the eastern plain area of>in the middle part of>in the western mountainous area.The distribution pattern of Cd is in the middle hilly tundra area of>in the eastern plain area of>in the western mountainous area.The distribution of Cr showed the pattern of>in the central part of>in the northern region.The distribution pattern of Cu shows the middle hilly tundra area of>in the western mountainous area of>in the eastern plain area.The distribution pattern of Zn content is the middle hilly tundra of>in the western mountainous area of>in the eastern plain.Pb distribution pattern is the pingyuan area in the east of>in the western mountainous area of>in the middle hilly tundra region.The distribution pattern of Ni content is the western mountainous area of>in the middle hilly tundra area of>in the eastern plain area.(7)Heavy metal element As was negatively correlated and positively correlated with Hg and Ni,respectively.There was a significant positive correlation between Hg and Cd,which was positively correlated with Cu but negatively correlated with Ni.Cd and Cu are positively significantly correlated with each other,and negatively correlated with Ni.There was a significant positive correlation between Cr and Ni.There is a significant positive correlation between Zn and Pb.(8)In the research region,the single factor pollution of heavy metal As,Hg,Cd,Cr,Cu,Zn,Pb and Ni of the farmland soil in the farmland of wutung town,gao Yang town,the town of yangquan town,and yangquan town of yangquan town in the region is less than 1,that is,it is not pollution grade.The comprehensive pollution index of nemero in wutong town,gaoyang town,dui town and yangquan qu town in the study area is all less than 0.7,which means that the farmland soil of four towns in the study area is in a clean(safe)grade(9)The comprehensive potential ecological risk index of wutong town and gaoyang town in the study area is between 110 and 220,and the total potential ecological risk is moderate.However,the comprehensive pollution potential ecological risk index of Yangquan qu town and dui town is between 220 and 440,and the total potential ecological risk is relatively strong.The overall potential ecological risk of the study area is relatively strong.In future agricultural production and planning management,attention should be paid to the scientific and reasonable planning and use of farmland soil.