Effects Of Amino Acids On The Transformation Of Iron Oxides And Active Organic Carbon Fractions In Paddy Soils Of North China

The content of iron oxide in soil is rich.The morphology,structure and properties of iron oxide are easily affected by environment due to their redox properties.Under the condition of flooding and anaerobic environment,the soil microorganisms are made of organic matter as electron donor,and Fe(?)can be reduced to Fe(?)by electron transfer.The process can alleviate the toxicity of heavy metals and inhibit the emission of methane,which is of great significance to the degradation and purification of organic pollutants.The amount of electron donor and acceptor in the soil is one of the factors limiting the iron oxide morphology and iron reduction,The addition of exogenous organic materials,on the one hand,can increase the number of soil electron donors to promote the reduction of Fe(?),in addition,by increasing the contact with the iron oxide,increasing the solubility of iron,promoting the activation of complex.In this study,the different types of China(brown,meadow soil and saline paddy soil type)as the research object,the indoor temperature of submergence and anaerobic culture method in different types of rice soil morphology features of iron oxide,By adding gamma polyglutamic acid,acid and two kinds of exogenous fertilizer synergist on paddy soil of iron reduction,iron oxides and active organic carbon fractions to study the effect of poly aspartic,and differences of two kinds of exogenous amino acids in the process of using paddy soil of different origin in the form of iron and iron oxide reduction,and investigated the relationship between the morphology of iron oxide and the relationship between iron reduction and soil active organic carbon fractions.The experimental results are as follows:(1)The content of free iron oxide In three typical paddy soils from high to low was:littoral saline soil>meadow soil>brown earth soil;the sequence of complex iron oxide content was brown earth soil>littoral saline soil>meadow soil;and the sequence of amorphous iron oxide was brown earth soil>littoral saline soil>meadow soil.(2)The effect of exogenous amino acids on the polymerization of iron oxides in paddy soil:the transformation of the different content of adding glutamic acid and polyaspartic acid on soil free iron oxide had no obvious effect;while adding glutamic acid can effectively increase the content of amorphous iron and chelated iron in paddy soil,improve the iron content in the soil,significant activation of iron oxide,iron inhibit aging of different types of rice soil;and polyaspartic acid on paddy soil amorphous and complex iron no significant priming effect.(3)The addition of ?-PGA and PASP could promote the microbial reduction process of iron oxides in various types of paddy soils,and the reduction ability of ?-PGA was stronger than that of PASP.Under the treatment of ?-PGA and PASP,the sequence of iron reduction in paddy soil was the same,the size of which was as follows:brown earth soil type,meadow soil type.(4)Different types of paddy soils Fe(?)the formation of a certain extent reduces the conversion of free iron,the crystallization is suppressed,at the same time,Fe(?)and positive correlation between amorphous and complex iron was that the reaction of soil iron oxides and iron compounds form:that is usually the degree of activation of iron oxide complex is more severe,more enhanced reactivity.(5)?-PGA promoted the accumulation of soil carbon pool and enhanced the stability of soil organic carbon pool.Three kinds of paddy soil treated by PASP while a certain extent improve the soil microbial biomass carbon proportion,but inhibited the transformation of soil in the decomposition of ROC in maintaining carbon stability and enhance the accumulation of soil organic carbon is better than ?-PGA.(6)Three ASOC group in paddy soil on contents and forms of iron oxides have certain relation,the content of ASOC increase can effectively prevent iron oxide precipitation,hinders the growth of crystalline iron oxides,organic matter and iron binding activity,through the reduction of the iron into the soil solution,and promote the activation of iron oxide from thus,inhibition of iron crystal aging.