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Beijing Forestry University (2020)

Effect of Microbial Agents on Soil and Plant in the Mu Us Desert

吴苗;

Titre : Effect of Microbial Agents on Soil and Plant in the Mu Us Desert

Auteur :

Grade : Master’s Theses 2020

Université : Beijing Forestry University

Résumé
Microbes play an important role in improving soil physical and chemical properties,increasing soil enzyme activity,altering soil microbial community structure,as well as facilitating plant growth and establishment.Currently,microbial agents have widely applied in the agricultural field ;however,they have not been extensively studied and estimated in sandy soils.To explore the effects of microbial agents on sandy soils and to screen out suitable microbial agents for soil improvement,this study conducted a control field experiment under two sand-fixing measures(sand-fixing nets and straw checkerboard barriers)with different treatments of microbial agents(sterile agent treatment,photosynthetic carbon-fixing bacteria,nitrogen-fixing bacteria,phosphate-resolving potassium-resolving bacteria,and compound bacteria)in the Mu Us Desert.Soil physical and chemical properties,Soil enzyme activity,microbial community structure,and plant growth in different treatments were observed and analyzed.The results are as follows :(1)Under two sand-fixing measures,soil microbial nitrogen,available phosphorus,and organic carbon content significantly increased by the application of microbial agents.Among them,photosynthetic carbon-fixing agents has the most significant improvement effect,followed by compound agents ;and microbial agents used in straw checkerboard barriers had better effects than that in sand-fixing nets.The soil acid phosphatase,N-acetyl-β-D-glucosidase,and phenol oxidase activities had been significantly increased by the application of microbial agents,with rates of 24.0%,17.1%,20.0%,and 22.1%,respectively ;and the enzymatic activities was higher in the straw checkerboard barriers than that in the sand-fixing nets.(2)The microbial agents enhanced the relative abundance of Proteobacteria,Actinobacteria,and Bacteroidetes.Owing to the application of photosynthetic carbon-fixing bacteria,the effects on Proteobacteria,Actinomycetes and Bacteroidetes were greater,followed by compound bacteria.The application of microbial inoculants increased the α-diversity of soil bacteria,of which Shannon showed a trend of decreasing first and then increasing,and also had a significant effect on the structure of soil bacterial communities.(3)By the application of the microbial agents,the plant growth was substantially improved,and the photosynthetic carbon-fixing and composite agents were the most striking agents in facilitating the growth and establishment of plants.The number of plants in the microbial agents treatments was small and the height was low.Among them,the plant growth status was worst in the non-microbial agents treatment,and there was almost no plant colonization and growth.Under the two sand fixation measures of sand fixing nets and straw checkerboard barriers,the coverage and height of plants in the straw checkerboard barriers higher than that under the sand fixing nets.Our results show that the application of photosynthetic carbon-fixing bacterial agents and compound bacterial agents have better effects on soil improvement.The microbial agents not only can fix sand,but also can promote the growth and establishment of soil microorganisms,improve the soil microenvironment,and facilitate the plant growth.Although higher costs,the microbial agents,as novel environmentally friendly materials,can be used to control desertification in desert areas.

Mots clés : Mu Us Desert; sandy soil improvement; photosynthetic carbon-fixing bacteria; compound bacteria; enzymatic activity; microbial community structure;

Présentation (CNKI)

Page publiée le 18 mai 2021