Emission Characteristics Of Greenhouse Gases Of CO₂ And CH₄ Under Long-Term Fertilization And Its Microbial Mechanism In Eum-Orthic Anthrosols Of Rain-Fed Farmland

To study the CO₂ and CH₄ emission characteristics and soil bacterial community characteristics of Eum-Orthic anthrosols in rainfed and dry land under different long-term fertilization treatments,establish a reasonable fertilization and management system,improve soil fertility through fertilization measures and improve soil biological characteristics.It is of great significance to reduce emissions and increase the stability and health of soil ecosystems.Long-term fertilization experiment was used to monitor winter wheat-summer leisure single cropping system in dry-soil control?CK?,single-application nitrogen?N?,nitrogen and potassium?NK?phosphorus and potassium?PK?,nitrogen and phosphorus?NP?,nitrogen,phosphorus and potassium?NPK?,organic fertilizer and NPK?MNPK?were used to treat CO₂ and CH₄ emissions.The physicochemical properties were combined with high-throughput sequencing technology.The effects of long-term fertilization on the physical and chemical properties and bacterial community structure of dryland farming and rainfed farmland were studied.This study draws the following results and conclusions:?1?The cumulative emission and emission flux of farmland CO₂ in different periods showed the highest MNPK treatment,significantly higher than NPK and NP,which was significantly higher than NK,PK and N,CK.The NEP of different fertilization treatments in the whole year is positive,which is the source of atmospheric CO₂ emissions.The NEP treated by MNPK,NPK and NP in the wheat season is negative,which is the absorption and sinking of atmospheric CO₂.Leisure is not conducive to the reduction of atmospheric CO₂.?2?The discharge of CH₄ in the rain-fed and dry-soil treatments is negative,and it is the absorption sink of atmospheric CH₄.The absorption flux and cumulative uptake of CH₄ in farmland in different periods were the highest is CK,significantly higher than NK,PK and N,significantly higher than NPK and NP,and MNPK was the lowest.?3?MNPK,NPK and NP treatment can increase soil microbial biomass carbon and soluble organic carbon and other nutrient contents,reduce soil pH,increase soil fertility and increase crop yield.CO₂ and CH₄ emissions from farmland were significantly negatively correlated with soil pH and positively correlated with other environmental factors.?4?Long-term fertilization can significantly increase soil bacterial copy number and change soil bacterial community composition.Organic and inorganic application also significantly improves soil bacterial diversity and reduces dominance.CO₂ and CH₄ emissions from farmland ecosystems were positively correlated with soil copy number,Shannon index,Chao1 index and ACE index,and negatively correlated with Simpson index and coverage index.MNPK,NPK and NP treatment can significantly affect the physical and chemical properties of farmland soils and CO₂ and CH₄ emissions,increase soil bacterial copy number and diversity,improve soil environment,improve soil fertility and increase crops under dry farming conditions in Guanzhong glutinous soil area.Yield,the absorption of atmospheric greenhouse gases can be achieved in the crop season.The simultaneous application of organic-inorganic and nitrogen-phosphorus fertilizers is of great significance for maintaining the stability and health of farmland soil ecosystems and productivity,and achieving greenhouse gas emission reduction and sustainable development of agriculture.