A Preliminary Study On Effect Of Soil Surface Electric Field On Nitrification In Acid Soil

Soil nitrification as the core of global nitrogen cycle,it affects the soil NH₄⁺ and NO₃ level and the level of soil fertility.As the surface soil particles with a large number of negative charge,in the Tuli near the surface and form a powerful electric field,which have a impact to the H⁺,NH₄⁺ and nitrifying bacteria(with the negative charge),thereby impact to soil nitrification.In previous studies, fewer people consider the role of the electric field on the surface soil particles,the paper from the soil surface different electric field impact to the soil nitrification activity.This study selected Chongqing in Jinyun Mountain pine forest soils(acid yellow soil pH 4.1),.Soil samples preparation by adding 5%and 10%of montmorillonite with ultrasound to crush the mixture, dried,crushed the 0.25 mm sieve.Through the sub-sample of the soil surface charge,microbial activity,nitrification activity,achieved the following results.Basis on constant know:the acid yellow soil surface charge density was -5.46×10^-2Cm^-2,and in acid yellow soil in the 5%and 10%concentration of montmorillonite,the surface charge density of particles were -1.08×10-1 Cm^-2,-1.13×10^-1C.m^-2,than the CK1 samples of a number of high-level. soil sample surface potential for -0.1162 V,and 5%and 10%concentration Montmorillonite deal with the soil samples of the surface potential were -0.1338 V and -0.1349 V;particle surface electric field strength,respectively:CK for -6.81×10⁷ Jm^-1.C^-1,5 percent for the processing of montmorillonite -1.35×10⁸ Jm^-1.C^-1,10percent for the treatment of montmorillonite -1.41×10⁸ Jm^-1.C^-1.So by adding montmorillonite to siol,the nature of the soil surface charge has markedly improved,adding 5%and 10%of montmorillonite soil samples nature of the surface charge increasing trend,but the increase was not obvious.Soil particles in different surface the electric field strength changed H⁺,NH₄⁺ activity.CK,5 percent of montmorillonite,10%of montmorillonite of soil pH were 4.4,5.5 and 6.0,with the particle surface of the electric field strength increases,the soil samples in the H⁺ activity decreased; NH₄⁺-N,H⁺ concentration in a similar change,soil NH₄⁺-N concentration in the CK,5 percent of montmorillonite treatment,and 10 percent of montmorillonite treatment were respectively 54.05 mg / kg,49.60mg/kg,23.44mg/kg,the reasons may be due to soil particles electric field on the soil of cations(H⁺,NH₄⁺,etc.)have absorption and reduce the cations in the soil of the activity.Soil particles of different electric field under the surface soil microbial activity changes:with the electric field the surface of the soil particles increased,the number of soil nitrifying bacteria were significantly reduced.As the soil nitrifying bacteria 10-1000 nm in size between,and soil and colloidal particles with a certain negative charge,soil colloidal particles exist between electrostatic force,So the soil electric field have an impact on the nitrifying bacteria activity.As the surface of the soil particles of the electric field strength increased,the soil nitrifying bacteria produce a certain exclusion,will cause the soil to reduce the number of nitrifying bacteria.In addition,the total soil nitrifying bacteria and soil nitrification no significant correlation,may be due to nitrifying bacteria and other micro-organisms with a considerable number of fixed NH₄⁺-N and result in soil nitrification rate changes;N content in soil microbial biomass.Three different treatment of soil samples in the microbial biomass N content:CK＞5%increase montmorillonite＞10%montmorillonit,with the electric field the surface of the soil particles increased,in the number of soil microorganisms reduced.In addition, in the process of preparation of samples,the role of ultrasonic grinder,destoried the microbial community structure.As soil microorganisms to environmental factors more complicated,because the restrictions on experimental conditions,may be too large errors.This article of the soil microbial biomass N and nitrification strength was linear negative correlation(r=-0.448);Soil respiration rate changes.Three samples of soil respiration:CK＞5%increase montmorillonite＞10%montmorillonite processing.Adding montmorillonite in soil samples,soil respiration rate is very weak,Which may be because the soil samples in the process of preparation after ultrasonic smash,causing extensive microorganism death;Changes in the activity of soil enzymes,soil particles of different electric field,soil urease activity performance:CK＞10%montmorillonite handling＞5%montmorillonite processing,Soil dehydrogenase,the activity of acid phosphatase showed:CK＞5%increase montmorillonite＞10% montmorillonite treatment.Surface soil particles increased after the electric field strength,soil urease, dehydrogenase,the activity of acid phosphatase are different levels of reduction were lower than without montmorillonite with the activity of soil samples,reaching the level of significant difference (p＜0.05);Nitrification of soil strength changes.In samples of the four-week training period,three soil samples with the size of nitrification potential for performance:10%montmorillonite handling＞5% increase montmorillonite handling＞CK.10%of montmorillonite treatment showed strong nitrification capacity in the soil during the entire train potential nitrification were significantly larger than the other two trraments(p＜0.05),and With three potential nitrification training time of the increase.As the surface of the soil particles of the electric field strength increased,decreased soil nitrification potential;The above results,in the soil by adding different concentrations of montmorillonite,increases the electric field strength,resulting in different soil nitrification,because the surface soil with a large charge,with their own soil microbes have an exclusive role,so that the soil nitrification decrease in the number of microbes,soil nitrification process have a certain impact.In addition,the nature of the soil particles of soil nitrification have an impact,soil organic matter to soil nitrifying bacteria are inhibited.As soil microorganisms to environmental factors more complex,particle surface electric field strength of soil microorganisms,the specific level of nitrification,pending further study.