Research Of Resistivity Variation And Influences Of Electric-amelioration On Salinization Soil

The amelioration of salinization soil and contaminated soil is the important task for theprevention and control of degradation and low yield soil, electromagnetic technology is one ofthe effective measures of degraded soil improvement, not only for the ionic contaminationsoil improvement, also used for monitoring ions migration in soil and groundwater, etc.cationic and anionic in the soil directional migrated and accumulated near electrode under adirect current field force, decreasing the scope and reduced costs, achieving both theeconomic and environmental benefits.Soil is a three-phase system, soil resistivity depends on the amount of charged particles、the character and the state of soil. Soil resistivity is the sensitivity index of ions content、soilelectric remediation technique parameter and the decisive factor of evaluation, at the sametime, as the basic indicator reflecting soil fertility characteristics which also have effect to thecorrosion speed of metal materials、grounding metal conductive and geological safety.Electric resistivity of soil affected by ions content, organic matter, soil texture, water contentand soil basic properties including porosity. It showed that soil resistivity is not only the stateof the soil properties, also the process attribute changed with soil property. Predecessors havedone effectively on the relationship between soil resistivity and ion content study. The factorsthat affect soil resistivity study are short on different ions, soil texture and soil structures; soilresistivity change with the directional migration of ion on a electric field force are still lacking.This topic according to ions migration of Saline soil under electric-amelioration settingdifferent soil substrates and soil water content indoor experiment was conducted. Study onboth soil resistivity change by ions migration under a electric field force and the factors(water content, salt types, soil textures, soil structures) affected soil electric resistivity.Aiming at monitoring and offering modified parameters of saline and contaminated soilimprovement. The conclusions are as follows:1. Electric resistivity is not only the soil state function, also the process function with soilion migration. Avoiding soil structure affected by ions migration under a electric field force, This paper used sand soil as a medium. The results showed that soil resistivity changeappeared obvious periodic fluctuations with ions migration under different voltages. the soilresistivity decreased slightly in the first10hours of electricity, while after10hours, the soilresistivity first increased dramatically, and then gradually reduced, accompanying with asharp change of soil temperature. Each treatment with different voltage showed significantdifference of soil temperature change.soil resistivity changed obviously under electric field force. Electric field force showeddifferent effects on active ions in soil solution and adsorbed ions on soil under differentelectrifying stages. When electric method is used to improve the salinity soil, both amoderate applied voltage and electrifying time are important conditions to remove soil activeions and latent ions.2. Ions directional migration make soil properties changed dramatically under a fieldforce. After30hours of electricity, Na+enriched in the cathode and Cl-concentrated in theanode on very short space; the soil pH also had obvious changes; the alkaline and acidicmigration zones were formed obviously in the soil column section, and the soil conductivitynear the cathode and anode increased significantly. The findings in this research showed ions’directional migration in soil.3. Water content and salt composition is the main factor affected ions directionalmigration in the soil under a electric field force. And the water content, salt content are themain factors influencing the soil resistivity. Resistivity range from big to small are15%>18%>21%with water content changes. soil electrical resistivity decreases with the soilmoisture content in a logarithmic form and decreases exponentially with the salt concentration.Soil resistivity has close relationship with salt type,soil resistivity with Na2SO4is significantly higher than soil containing NaCl at the samesalt content; Salts composition (double salts) in the soil have evident influence on resistivity.Sulfate salt have obvious effects on soil resistivity in sand soil when the salt content less than0.5%and the influence of carbonate significantly while the influence of the chloride saltgenerally small when Salt content is more than0.5%. The results showed that easy migrationof soil salt ion impact on the change range of soil resistivity less than difficult to migration ofsalt ions. Also means resistivity method can used to both detect the salt concentration anddiagnosis of salt type.4. Soil texture and structure types such as physical properties are the important factorsthat affected soil resistivity. Texture and structure characteristic determines the soil pore characteristics and continuity, which affecting soil resistivity during electricity and ionicmigration. soil resistivity of larger diameter aggregate is significantly higher than smalleraggregate, that because the larger diameter had a higher proportion of space which have highresistivity. Loess soil, for example, soil resistivity along with the change of the aggregate is5-3mm>3-2mm>1mm>2-1mm under the same water content. The effects of texture types tosoil resistivity depends on the electrical conductivity of solid particles in the soil. Sand grainbelongs to the original mineral, its resistivity is greater than silt and clay soil; Sand soilresistivity higher than Leached drab soil, Argillic horizon of soil, Loess subsoil. The latterthree soil resistivity difference was not significant in the process of electricity.In soil electric-amelioration charged ions in a dynamic process, soil resistivity haveperiodic fluctuations with the extension of current time in the process of the whole electricity,it showed that soil resistivity fluctuations reflects the mechanism and progress of ionmigration.