Study On Soil Remediation Technology And Microbial Response Mechanism Of Salinized Farmland In Shannan,Tibet

Soil salinization will have a serious negative impact on soil health and agricultural production.Microorganisms are the most active part of the soil.It is of great significance to explore the remediation methods of soil salinization and the response mechanism of microbial communities during the restoration process.The soil environment of the Tibetan Plateau is fragile,and the microorganisms in the salinized soil face the dual pressure of extreme plateau environment and salinization.In this study,the response mechanism of the microbial community in the saline soil in the south of Tibet to the environment was studied.Then,using guest soil mulch and new bio-organic fertilizer to repair the saline soil,selecting the typical Tibetan crop highland barley as the experimental crop,comparing bio-organic fertilizer with traditional inorganic fertilizer fertilization methods,from the soil properties,highland barley yield,rhizosphere microbiome and Microbial metabolic potential evaluates the effect of soil remediation from multiple angles,and attempts to establish an interaction relationship between soil-crop-microbial communities.The paper mainly draws the following conclusions:(1)The composition and function diversity of microbial communities in saline soil and non-saline soil are obviously different.Soil properties such as EC,TOC,and p H have shaped a unique microbial ecological group.Under the dual pressure of soil salinization and the extreme climate of the plateau,compared with non-saline soil,the chemical autotrophic and acidophilic bacteria clusters in saline soil are more abundant;and in saline soil,organic carbon degradation and denitrification are produced.The metabolic potential of NO and N2 O,and sulfur oxidation to produce sulfate are higher;at the same time,both types of soil are rich in genes that are resistant to environmental stress(ie,cold,ultraviolet light and hypoxia in the Qinghai-Tibet Plateau).(2)Remediation was carried out by mulching with guest soil and bio-organic fertilizer.At the same time,comparing bio-organic fertilizer with traditional inorganic fertilizer fertilization methods,it was found that different fertilization treatments caused significant changes in microorganisms.In addition,compared with the application of chemical fertilizers or organic fertilizers alone,mixed fertilization has a slower but lasting effect on the promotion of microbial biomass,making the rhizosphere microbial network pattern more compact and complex,and enhancing the resistance of the barley rhizosphere to microbial invasion and environmental pressure,to promote soil nutrient cycling.(3)Fertilization not only caused changes in the microbial community,but also found that mixed fertilization had better soil remediation and yield increase effects than organic fertilizer or chemical fertilizer alone.The p H of mixed fertilization is the closest to 7,TOC,C/N,thousand-grain weight,plant height is the highest,and chemical fertilizer is the lowest.Mixed fertilization has the best promotion effect on highland barley thousand-grain weight,plant height and estimated yield.Key indicator species also have a significant promotion effect on highland barley yield.This work has conducted a preliminary analysis of the microbial community of the saline soil in Tibet,and applied new bio-organic fertilizers to repair the saline soil,and clarified the adaptation of the soil saline environment and the microbiome under extreme climatic environmental pressure on the plateau from the species composition and molecular level.It also provides help for the restoration of Tibetan saline soil,the increase of barley production,and the characterization of the rhizosphere microbiome of barley.