| In this study,the pH,organic matter(OM),bulk weight(BD),mechanical particle size(SMC),agglomerate structure(SA),water-soluble salts(SSS),cation exchange capacity(CEC),fast-acting nitrogen(AN),total nitrogen(TN),total phosphorus(TP),total potassium(TK),effective phosphorus(AP),slow-acting potassium(SK),fast-acting potassium(AK),effective copper,zinc,iron and manganese were analysed by sampling and investigating typical high diving level arable soils in the Huaihe River basin,taking into account the actual situation of agricultural land in Huainan.(TP),total potassium(TK),effective phosphorus(AP),slow-acting potassium(SK),fast-acting potassium(AK),effective copper,zinc,iron and manganese,as well as the spatial distribution of nine heavy metals in the soil:cadmium,chromium,lead,arsenic,copper,zinc,nickel,titanium and manganese.The numerical and comprehensive evaluation of soil fertility was carried out using principal component analysis,and the evaluation and analysis of the risk of soil heavy metal pollution was carried out using the Nemero comprehensive index method and the potential ecological risk evaluation method,on the basis of which the comprehensive soil quality condition was evaluated and studied using the soil quality index method.And ArcGIS10.6 was used to produce a spatial distribution map of the comprehensive fertility of agricultural land in Huainan City as well as a spatial distribution map of heavy metal content.The main conclusions of the study are as follows.1.The soil texture of the agricultural land in the study area is a chalky loam with mean OM,AP,AK,SK,TN,AN,TP and TK contents of 19.33 g·kg-1,4.78 mg·kg-1,210.71 mg·kg-1,418.46 mg·kg-1,1.10 g ·kg-1,42.13 mg·kg-1,0.09%,23.60 g·kg-1;respectively.SSS mean 4.14 g·kg-1;CEC mean 14.48;pH mean 7.21;BD mean 1.40 g/cm3;macroagglomerates mean mass 1.87 g,mean 46.67%,microagglomerates mean mass 2.14 g,mean 53.33%;soil trace elements The mean values of effective Cu,Zn,Fe and Mn were 1.86 mg·kg-1,0.90 mg·kg-1,18.18 mg · kg-1 and 20.45 mg·kg-1,respectively.pH,OM,AN,AP,AK and TN contents of agricultural soils in the study area were relatively low compared to those of agricultural lands in low diving areas,and the soil trace element contents were also relatively low.2.The content of heavy metals in agricultural soils in the study area varied widely by species,with Cr,Mn,Ni,Cu,Zn,As,Cd,Pb and Ti ranging from 43.40 to 68.84 mg·kg-1,275.99 to 503.78 mg·kg-1,17.04 to 30.76 mg·kg-1,7.73 to 22.29 mg·kg-1,29.26～61.34 mg ·kg-1,4.01-9.90 mg·kg-1,0.01-0.07 mg·kg-1,12.53～18.00 mg·kg-1 and 3039.10～3854.60 mg · kg-1.The arithmetic mean values were 57.07 mg · kg-1,409.80 mg ·kg-1,25.34 mg·kg-1,14.77 mg·kg-1,44.50 mg·kg-1,7.42 mg ·kg-1,0.02 mg·kg-1,16.26 mg · kg-1 and 3529.39 mg · kg-1 respectively.study area Soils on agricultural land contained lower levels of the heavy metals Cr,Ni,Cu,Zn,As,Cd,Pb and Ti,but relatively higher levels of the heavy metal Mn,than agricultural land in the low dive site area.3.The results of the principal component analysis of the nutrient indicators of Huainan agricultural land show that the IFI values of the soil samples in the study area are distributed between-1.5042 and 0.6587.There were no Grade 1 or 2 lands with high fertility levels,Grade 3 lands with medium fertility levels accounted for 62.5%,Grade 4 lands with low fertility levels accounted for 25%and Grade 5 lands with poor fertility levels accounted for 12.5%.4.The results show that the Nemero Composite Index,the Ground Accumulation Index,the Pollution Load Index and the Hakanson Potential Ecological Risk Evaluation Method were used to evaluate and analyse the pollution status and potential risks of soil heavy metals in the study area.The mean and maximum values of 0.7356 and 0.8891 respectively,with a coefficient of variation of 13.42%,are at medium variation intensity,and the pollution levels are at the safe and alert limit levels,indicating that the soil heavy metals in the study area are slightly polluted;the ground accumulation indices of the mean values of the nine heavy metals are-1.2666,-1.5955,-0.9229,-1.6396,-0.9950,-0.9261,-9.6097,-1.1175 and-1.1131,all of which are less than 0,all of which are graded as 0,and all of which are non-polluting;the overall PLI index of the study area is much less than 1,indicating that the pollution in the study area is extremely light and the pollution level is non-polluting.The overall ecological risk index of the study area is 20.8114,and the ecological risk level is slight.The potential ecological risk coefficients of the nine heavy metals at each site are all less than 40,and the comprehensive ecological risk index of each site is far less than 150,indicating that the ecological risk level of each site is very low.5.The soil quality index(SFI)method was used to evaluate the soil quality of the study area by combining the content of soil nutrient indicators and heavy metal elements in the study area.The results show that the SFI-AVE of the soils in the study area ranged from 0.4 to 0.8,with a mean value of 0.6731 and a coefficient of variation of 14.08%;the PI-AVE ranged from 0.4 to 0.7,with a mean value of 0.5924 and a coefficient of variation of 15.29%;the SQI ranged from 0.8 to 1.5,with a mean value of 1.2461 and a coefficient of variation of 14.86%.The SQI ranged from 0.8 to 1.5,with a mean value of 1.2461 and a coefficient of variation of 14.86%.Figure[59]Table[29]Reference[117]... |
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