The Interaction Between Soil Microorganisms And Humic Acid Of Zhaotong Lignite

China's brown coal resources are huge,about 130 billion tons of reserves.Zhaotong brown coal is located in the northeast of Yunnan Province,which is one of the youngest brown coal resources in the world.The resource area of Zhaotong brown coal is about 230 million square kilometers and its reserves are extremely rich.However,Zhaotong brown coal has high water content,high ash content and poor thermal stability,which makes it impossible to carry out the traditional application of Zhaotong brown coal.While Zhaotong brown coal is rich in humic acid,and humic acid is a high-quality raw material for production,it is becoming the development direction of ecological agricultural fertilizer in the 21^stt century.Therefore,extracting Zhaotong brown coal humic acid and carrying out its application in the field of soil fertilizer is a feasible way to use Zhaotong brown coal.Humic acid is a complex structure of macromolecular compounds.When humic acid is applied to the soil,its degree of degradation in the soil,as well as changes in soil properties,can have an impact on its application.In this paper,Zhaotong brown coal humic acid was used as raw material to investigate the interaction between soil microorganisms,and Zhaotong brown coal humic acid in three different media?PDA,Gaoshi No.1,beef graft peptone?in the condition presence and absence of soil and minerals.It is planned to do some basic research work on the application of Zhaotong brown coal humic acid in the field of chemical fertilizers.In this study,the degradation rate of humic acid,molecular weight distribution,E₄/E₆ value and the change of soluble carbon content in culture environment were used to characterize the degradation of humic acid,and the microbial biomass carbon was used to characterize soil microorganisms.The impact studies have shown that:?1?In the absence of soil and minerals,Zhaotong brown coal humic acid will degrade under the action of soil microorganisms.Among them,in the PDA media,when the pH of the humic acid solution was added of 5,soil microorganisms with fungi as the dominant species have the highest degradation rate of free humic acid,which was 53.33%,and the weight average molecular weight of humic acid could be reduced to 45455.The value of E₄/E₆ can be changed from the original of 3.89 to4.08;in the media of Gaoshi No.1,when the pH of the humic acid solution was added of 7,soil microorganisms with actinomycete as the dominant species have the highest degradation rate of free humic acid,which is 30.11%,and the weight average molecular weight is reduced to 45339.In the media of beef graft peptone,when the pH of humic acid solution was added of 7.5,soil microorganisms with bacterial as the dominant species have the highest degradation rate of free humic acid,which was25.27%,and the weight average molecular weight is reduced to 50997.The results showed that the soil microorganisms under different media conditions had different degradation abilities to humic acid,and the degradation effect order of free humic acid was:PDA>Gao shi No.1>Beef Graft Peptone.?2?In the absence of soil and minerals,the microbial biomass carbon in the three mediums was changed:under the media of PDA,when the pH of the humic acid solution was added of 5,the microbial biomass carbon in the solution increased to5182mg/kg.Under the media of Gaoshi No.1,when the pH of the humic acid solution was added of 7,the microbial biomass carbon in the solution increased to 5623mg/kg;under the media of beef graft peptone,when the pH of the humic acid solution was added of 7.5,the microbial biomass carbon in the solution increased to 3560mg/kg.The effect of Zhaotong brown coal humic acid on soil microbes under high growth rate was significant.The order of humic acid on soil microbial growth under different media was:Gao shi No.1>PDA>Beef graft peptone.?3?In the environment of montmorillonite,bauxite,kaolin,mixed minerals of three minerals and Kunming soil,the change of microbial biomass carbon in three mediums was:under the media of PDA culture,the microbial biomass carbon increased to 2194,1992,2198,1801,1776,1308mg/kg,under the media of Gaoshi No.1,the microbial biomass carbon increased to 1329,1673,691,984,1148,554mg/kg,under the media of beef graft peptone,the microbial organisms carbon increased to 1149,1042,1670,1312,931,753mg/kg.In the presence of different soils and minerals,the growth and reproduction of microorganisms will be different.The influence of order on microorganisms in different media is:PDA>Gao's No.1>Beef Peptone.?4?In the environment of soil and minerals,humic acid can promote the growth and reproduction of microorganisms,but the effect of increasing the number of microorganisms has no significant effect to free humic acid,mainly due to the adsorption of humic acid by clay minerals such as soil and minerals,protects against humic acid.?5?By FTIR and GPC characterization with humic acid was before and after culture process,it was found that the humic acid had a large change in the functional group structure and molecular weight distribution.