Response Of Soil Bacterial And Autotrophic Carbon Sequestration Microbial Diversity To Tillage Measures In Semi-arid Area Of Loess Plateau

Soil microorganisms play a large part in CO₂ fixation.Autotrophic microorganisms are commonly distributed in soil and possess high potential for environmental adaptability and carbon sequestration.In 2019,traditional farming?T?and three forms of conservation tillage,namely no-till straw cover?NTS?,no-till don't cover?NT?and modern tillage straw digging?TS?of pea farmland soil carbon sequestration and emissions,were studied in this report,based on 2001 in Gansu district,in order to create a long-term experiment of various farming steps,Rubisco enzymes and their encoding genes?cbbL?,the use of soil microbial sources of carbon and the effect of physical and chemical properties,such as rainfed soil bacteria and photosynthetic carbon microbial diversity measures to cultivate and get the results.The results show that:1.Compared to conventional tillage?T?,conservation tillage significantly increased the content of organic carbon,total nitrogen and phosphorus available in the0-20 cm soil layer during the peas flowering season,the most important of which was non-tillage straw mulching?NTS?.Straw mulching and tillage had major effects on soil organic carbon in the soil layer of 0-20 cm,and soil organic carbon content in the soil layer of 0-20 cm was NTS,>,TS,>,NT,>T.The NTS treatment's soil organic carbon content increased by 26.2 percent compared to that of T treatment,and the carbon sequestration improved dramatically.2.Straw mulching significantly increased Rubisco's enzyme activity in the 0-20cm soil layer but there was no significant tillage effect.Rubisco's enzyme production in soil treated with NTS and TS increased by 63.4%and 95.2%,respectively,relative to conventional tillage?T?,with no substantial difference between T and NT treatments.3.The carbon metabolic diversity of soil microorganisms has been defined by capacity utilization of the carbon source and the index of functional diversity.The amine<carboxylic acid<poly<carbohydrate<amino acid<phenolic acid was the order of utilization strength of six carbon sources by soil microorganisms under different tillage steps.NTS'consumption ability for six types of carbon sources?carbohydrates,amino acids,polymers,phenolic acids,amines,carboxylic acids?improved by 69.4%,45.7%,49.8%,57.4%,9.8%,52.2%,respectively,relative to T.Diversity of soil microbial population metabolic activity under the various tillage measures NTS>TS>T>NT.4.Tillage interventions had a substantial effect on soil microbial population abundance in the 0-20 cm soil layer,and microbial species richness and diversity under NTS treatment was higher than in NT,TS,and T treatment.In NTS treatment,the bacterial population richness index?Chao1?increased by 4.7%relative to T,while NT decreased by 7.5%.Chao1 NT The variation pattern of OTU is similar at the phylum and class level,that is,NTS>,TS>T>NT,while at the level of order,family,genus and species,the variation trend of OTU is TS>,NTS>T>NT.There are7 phyla,5 classes,12 orders,24 families,41 genera and 60 species of autotrophic microorganisms containing cbbL carbon fixation gene,including 7 dominant phyla,including Actinobacteria,Proteobacteria,Chloroflexi,Planctomycetes,Verrucomicrobia,Cyanobacteria and candidate division NC.Straw mulching increased Proteobacteria relative abundance,but decreased Cyanobacteria relative abundance?P<0.05?.In summary,long-term no-till straw mulching can increase the diversity and richness of the soil bacterial community in semi-arid areas of the loess plateau,as well as the capacity of carbon source utilization and the metabolic function diversity of self-supporting carbon sequestration microorganisms,this is of great importance for improving soil quality,increasing soil carbon sequestration and promoting sustainable dryland productivity improvements.