| ObjectivesA cross-sectional investigation on the surface soil characteristics in commensal rodent plague foci during the rest period of plague was conducted to analyze the distribution differences of the soil characteristics under different plague occurrence conditions and the correlation among the soil characteristics,to explore the relationship between plague and soil characteristics,so as to provide baseline data for the assessment of plague risk,and for the effective control and prevention of plague.MethodsFrom July to August in 2019,soil samples were collected from the plague foci of Mile,Mangshi and Lianghe county,Yunnan.The sampling sites were divided into 8 plague villages and 8 non-plague villages according to the occurrence of plague.A total of 230 soil samples were collected and the land use patterns were recorded.Munsell colorimetric card method was used to identify the soil color.Dry matter content was determined by drying method,p H was determined by potentiometric analysis,and electrical conductivity was determined by electrode method.Organic matter was determined by potassium dichromate oxidation external heating method.Seven metal elements including Fe,Ca,Ti,Co,Cu,Ni,V were determined by microwave digestionICP-OES.Microsoft Excel 2019 was used to input and sort out the data.SPSS 26.0 was used for statistical analysis.Chi square test,Wilcoxon signed rank test,Kruskal Wallis H test and Mann Whitney U test were used to analyze the differences of soil characteristics distribution in different regions,soil color,land use and plague occurrence.Spearman’s rank correlation was used to analyze the correlation of soil characteristics.Results1.The classification and detection of 230 soil samples showed that the color was classified into five kinds,red,brown,yellow brown,red yellow and gray brown,with a median p H of 5.82,which was lower than that of Yunnan.The median of electrical conductivity was 166.51 μs /cm,and the median of organic matter was 21.19 g/kg.There were rich in Fe,Ca and Ti,and Cu,Ni and V were lower than other metal elements.2.The overall distribution of soil characteristics in different regions was not consistent(all P<0.05).Mile soil color includes red,brown and yellow brown,Mangshi soil color includes brown,yellow brown and red loess,and Lianghe includes brown,yellow brown,red yellow and gray brown.Mile soil had the highest acidity,conductivity,Fe,Ti,Co,Cu,Ni and V(all P<0.017).Lianghe soil had the highest Ca(all P<0.017).3.The overall distribution of soil characteristics under different soil color was not consistent(all P<0.01).The red loess had the highest acidity and the lowest conductivity and organic matter.The contents of Fe,Ti,Co,Cu,Ni and V were the highest in red soil,and the lowest in grey brown soil.The content of Ca in brown soil was higher than that in yellow brown soil,and that in yellow brown soil and grey brown soil was higher than that in red soil and red loess(all P<0.01).4.The overall distribution of p H,organic matter,Ca,Cu,Ni and V was not consistent(all P<0.05),and the organic matter of cultivated land and woodland was higher than that of grassland.The acidity of forest land was higher than that of grassland.The content of Ca was the lowest,Cu and V was higher than that of grassland,and Ni was higher than that of cultivated land(all P<0.017).5.In the comparative analysis of different plague occurrence conditions,the contents of Ni and V in plague villages were lower than those in non-plague villages(P<0.05).The conductivity and the contents of Fe,Ti,Cu,Ni and V in plague villages were lower than those in non-plague villages in Mile.The contents of organic matter,Ti,Co and Cu in plague villages were higher in Mangshi.And the electrical conductivity and the content of Ti in plague villages were higher in Lianghe(all P<0.05).6.There were correlations among soil characteristics.p H is positively correlated with Ca and Co,conductivity was positively correlated with p H,organic matter,Ca and Cu,and organic matter was positively correlated with Cu.Ca had no correlation with Ti and Co,but had a negative correlation with Fe,Cu,Ni and V,while the other six elements showed positive and strong correlation.Conclusions1.The soil in the sampling area of commensal rodent plague foci in Yunnan was acidic and slightly salinized on the whole.The organic matter index of soil nutrients was Grade III medium,and the types and contents of metal elements were rich.2.Mile was mainly red soil,Mangshi was mainly brown soil,Lianghe was mainly brown soil and wide color.The red loess soil has the highest acidity and the lowest conductivity and organic matter.The contents of Fe,Ti,Co,Cu,Ni and V in red soil were the highest,while the contents of Ca in gray brown soil were relatively high,and the contents of other elements were relatively low.The distribution of metallic elements in different soil colors and different regions was basically the same.3.The distribution of soil characteristics was different with different land use patterns.The acidity of forest land was stronger,the contents of organic matter,Cu,Ni and V are higher,and the content of Ca was the lowest.4.The differences in the contents of certain metal elements under different plague occurrence conditions were the same as those causing plague outbreak,but did not reach the rise and fall times of plague outbreak.Moreover,there were differences in some elements under different epidemic conditions in different regions,suggesting that it is necessary to monitor the changes of metal elements in different regions continuously and dynamically to prevent and control plague outbreak.5.Correlation distribution of soil characteristics under different plague occurrence conditions was basically the same.There was a close correlation between soil properties.Ca and Fe,Cu,Ni and V were all negatively correlated,while the other six elements were all positively and strongly correlated. |
PDF Full Text Request