Study On Soil Microbial Diversity And Enzyme Activity In Maize Field Under Fenlong Cultivation

As a traditional agricultural country,China has a long history of agricultural production.Choosing suitable farming methods is a very important factor in improving the quality of cultivated land in the Yellow River irrigation area.Fenlong cultivation is a new type of farming technology that can significantly increase the yield of crops and is one of the protective farming methods to improve the quality of farmland.However,little is known about the dynamics of soil microorganisms and soil micro-ecological changes under Fenlong cultivation.This study was conducted in Touzha Village,Pingluo County,Shizuishan City,Ningxia.The corn variety "Dika No.5" was used as the test material,and the large-area experimental design was adopted,and conventional tillage depth of 20cm(CK),Fenlong cultivation depth of 35cm(FL1)and Fenlong cultivation depth of 50cm(FL2)were set to treat the corn farmland.The focus was on the effects of different tillage depths on soil enzyme activity,soil microbial community diversity and functional diversity,and the response of soil enzyme activity,microbial composition and functional diversity to Fenlong cultivation was explored.Thereby increasing the research on the soil micro-habitats under Fenlong cultivation,and correspondingly explain the mechanism of how Fenlong cultivation affects the soil microecology,which had an impact on the sustainable development strategy of cultivated land quality in the agricultural system of the Yellow River irrigation area in western China.The main research results of our study are as follows:(1)Fluorescence quantitative PCR technology was used to measure the bacterial abundance of different treatments in each growth period,which showed that the copy number of 16S rRNA gene in each treatment was FL1>FL2>CK.During the reproductive period,FL1 was significantly increased by 49.31%-194.07%compared with CK,and FL2 was significantly increased by 8.28%-73.27%compared with CK.The results show that Fenlong cultivation could significantly increase the abundance of bacteria,which is expressed as:FL1>FL2>CK.(2)Illumina Miseq sequencing results show that in each growth period,Fenlong cultivation could lead to an increase in the a diversity of soil bacterial communities,which is expressed as:FL1>FL2>CK.Principal co-ordinates analysis(PCoA)and Hierarchical clustering tree concluded analysis show that,except for the seedling stage,the Fenlong cultivation technology significantly affected the structure of the soil microbial community,which was expressed as:FL2>FL1>CK.At the phylum level,Fenlong cultivation significantly increased the abundance of Actinobacteria?Proteobacteria?Chloroflexi?Acidobacteria?Gemmatimonadetes?Bacteroidetes and Firmicutes.The analysis of bacteria classes found that Actinobacteria?Alphaproteobacteria?Vicinamibacteria?Chloroflexia?Gammaproteobacteria and Thermoleophilia were the dominant classes(relative abundance>5%).These results indicate that Fenlong cultivation may increase the heterotrophic flora(such as Actinomycetes,Proteobacteria,Bacteroides,etc.)to accelerate the nutrient circulation in the soil and improve the quality of cultivated land.(3)Tax4Fun function prediction analysis shows that soil bacteria in corn farmland was mainly involved in four primary metabolic pathways:metabolism,genetic information processing,environmental information processing,and cellular processes.There were significant differences in 14 secondary metabolic pathways including carbohydrate metabolism,lipid metabolism,and energy metabolism.The overall trend of bacterial metabolism was:FL1>FL2>CK.(4)Compared with CK,FL1 and FL2 significantly improved the activities of soil urease,invertase,alkaline phosphatase and catalase in each growth period,and FL1 improved the activities of four soil enzymes better than FL2.(5)Biolog-ECO results showed that Fenlong cultivation significantly improved the soil microbial functional diversity index and carbon source metabolism capacity,which was FL1>FL2>CK.The carbon sources used by soil microorganisms are mainly amino acids,polymers and carboxylic acids.Fenlong cultivation cultivation significantly improves the utilization of carbon sources of sugars,amino acids,polymers,amphiphiles,amines and carboxylic acids.Compared with FL2 and CK treatments,FL1 significantly improved the ability to utilize carbon sources,and there were significant differences in the utilization of 31 single carbon sources by soil microbial communities in each treatment.Fenlong cultivation could significantly change the structure of soil microbial community,which was expressed as:FL1>FL2>CK.(6)Correlation analysis showed that there was a significant correlation between soil enzyme activity,bacterial phyla and 6 types of carbon sources.Through the establishment of a path analysis model,it is found that Fenlong cultivation treatment makes the relationship between various control factors and microbial functional diversity more obvious.It mainly affects soil bacterial abundance,bacterial community diversity,and enzyme activity through direct and indirect methods to regulate microbial functional diversity.In summary,Fenlong cultivation could indirectly or directly affect soil microbial functional diversity and carbon source metabolism by increasing soil bacterial abundance,soil bacterial community structure diversity,bacterial functional groups and soil enzyme activity,and it promotes microbial activity and nutrient cycling.Based on the above analysis from the perspective of soil microorganisms,Fenlong cultivation can improve the soil environment,promote microbial activity and nutrient cycling,and is an effective measure to improve the quality of soil cultivated land,and the best Fenlong cultivation depth of 35cm.This studied provides a scientific basis for the application and development of Fenlong cultivation technology in crop cultivation in the Yellow River irrigation area in Ningxia.