Geochemical Evaluation Of Soil Quality Of Cultivated Land In Muguo Town,Shuicheng County,Guizhou Province

China is one of the countries with large desertification and desertification area,wide distribution and serious harm in the world.It represents one of the countries with the most serious soil and water loss.The area and scope of soil and water loss are large and wide.Both soil and water loss and land desertification seriously affect and destroy agricultural production conditions,deteriorate the ecological environment and affect the quality of soil.How to solve the problem of the decline of cultivated land quality? Solving the problems of soil erosion,improving soil fertility,adjusting unreasonable land structure,and how to improve the sustainable use of land has become a hot research topic at home and abroad.In order to actively respond to the national call of "keeping the land clean" and "speeding up the development of high-efficiency agriculture with modern mountainous characteristics",the geochemical investigation and evaluation of cultivated land quality in Guizhou Province has been carried out.In this paper,combined with the geological topography,geomorphology,agricultural types and geochemical element characteristics in the study area,geochemical spatial distribution characteristics of soil in the study area were studied by using geostationary and statistical methods.On this basis,nutrient geochemical grade of nutrient elements in the study area was divided,and single factor index method and geological accumulation index method were used to study.Soil environmental geochemical grading of 8 harmful elements in the study area was classified,and the sources of 8 harmful elements in the study area were analyzed by correlation analysis,cluster analysis and human influence factors.The following conclusions are drawn:1)Whether using a single factor index method or geological accumulation method,the content of copper in the study area pollutes the soil.The single factor index method shows that the pollution index of copper and cadmium in the study area is 3.95 and 3.6,and the environmental geochemical grade of the two areas is grade 4 moderately heavy pollution,which is serious pollution.The single factor index method shows that about 47.71% of the area of copper in the whole region is heavily polluted and 44.24% of the soil is moderately polluted.The proportion of moderate and severe Cd pollution was 49.36% and 38.81% respectively.The content of harmful elements in the soil in the South and southwest of the study area is high,which is a heavily polluted area.Northeast of the study area is a moderately polluted area.2)The content of Se and Ge in the study area is very rich,which can be rated as Se-rich and Ge-rich.It has the potential to develop local characteristic products such as Se-rich kiwi fruit and Se-rich tea.3)The soil nutrient geochemical grade of cultivated land in the study area is second grade,and the nutrient content is relatively rich.92.32% of the soil nutrient geochemical grade is second grade,and the nutrient content is relatively rich.The southwest corner of the study area has a low nutrient content,and the nutrient geochemical grade is three grades.Other areas have a second grade of nutrient geochemical grade and abundant nutrient content.The area is rich in nitrogen,phosphorus and potassium.The contents of nitrogen and phosphorus are very rich,but the content of potassium is relatively deficient.4)The comprehensive soil environmental geochemical grade in the study area is grade 5.Although nutrients are abundant,the pollution of copper and cadmium in the study area is serious,so the comprehensive soil quality geochemical grade is grade 5 inferior soil.The proportion of 5-grade inferior soil and 4-grade inferior soil in the rehabilitated area is 56.49% and 40.04% respectively.The overall soil quality is poor,so it is necessary to comprehensively control the soil in the study area.5)The environmental geochemistry of harmful elements in the study area was divided by a single factor index method.Pollution degree of harmful elements in soil was as follows: Pb<As<Hg<Zn<Ni<Cr<Cd<Cu.6)Nitrogen and phosphorus are abundant in the study area.Nutrient geochemical grades are all first-class,potassium is low,nutrient geochemical grades are 5,potassium is deficient,organic matter is abundant,and nutrient geochemical grades are first-class.7)The sources of organic matter and molybdenum,nitrogen and selenium in the study area are similar to each other,and their migration and enrichment in soil are also affected by similar factors.8)It is speculated that the influencing factors of Ni,Zn and Cd may be industrial wastes such as waste water and exhaust gas produced in the smelting process.Both Pb and As may be caused by the use of pesticides containing Pb,As and Hg in the cultivation process of local residents.However,Cr,Cu and Hg may be affected by many factors.