Effect Of Different Tillage Methods On N₂O Emissions From Wheat Fields Based On Meta-analysis

Climate change and greenhouse gas emissions are the hot spots of global concern.The global warming caused by the increase of greenhouse gas emissions is becoming more and more intense.Nitrous oxide?N₂O?,as an important member of greenhouse gas,is 190 to 270times higher than CO₂ in warming potential,and farmland soil is the most important N₂O emission source in the world.Generally,it is believed that N₂O in farmland soil is mainly generated by nitrification and denitrification,and environmental factors and management measures also affect N₂O emissions by affecting these two processes.However,the impact of different tillage methods on N₂O emissions is still controversial.Therefore,to explore the effects of different tillage methods on N₂O emissions on a large scale and to understand the cross effects between different tillage methods and other environmental factors has certain guiding signify-cance for N₂O emission reduction in farmland.Meta-analysis refers to a statistical method of integrating and comparing multiple resear-ch conclusions obtained for a certain problem.By summarizing and summarizing the results of many independent studies on the same topic,the results of the research problems are more regular and closer to the essence,and the results are closer to the objective facts.This study is based on a number of literature data published before 2018 on N₂O emissions from wheat fie-lds under different tillage methods.Using the meta-analysis method,the quantitative analysis of N₂O emissions is conducted to obtain the effect of N₂O emissions under different tillage methods and the interaction between tillage methods and other soil factors.Main research re-sults and conclusions are as follows:?1?Meta analysis showed that tillage significantly increased N₂O emissions in wheat fie-lds compared with no-tillage,with an increase of 13.20%.Compared with no-tillage,rotary ti-llage can reduce N₂O emission,but the reduction effect is not obvious?P<0.05?,and the re-duction range is 1.31%.Compared with no-tillage,deep pine significantly increased N₂O emission by 30.25%.?2?the influence of different farming methods to the cornfield N₂O emissions in fact is a surface phenomenon,which is essentially due to the different farming methods based on soil produce different forms and levels of disturbance to alter its internal uniformity,permeability and nutrient content distribution,related microbial content and distribution,soil moisture con-tent and different factors such as soil temperature,and indirectly influenced N₂O production and emission.These factors can be divided into two categories according to their different de-grees of influence on N₂O emission,one is the key factor,the other is the non-key factor.?3?Meta analysis showd that N₂O emissions from wheat fields under different tillage me-thods will change regularly with soil moisture content,straw mulching and fertilization,whic h is also the cause of heterogeneity.Therefore,these three factors are the key factors affecting N₂O emissions from wheat fields.All the three directly provide material and energy source fo r the generation of N₂O,and indirectly influence the generation and emission of N₂O through the cross action with other subcritical factors.According to its influence on N₂O emission in wheat fields under different tillage methods,the order of the three is soil water content>ferti-leizing>straw to return to the field.?4?Meta analysis showed that although N₂O emissions from wheat fields under different tillage methods changed with soil texture,carbon and nitrogen ratio,pH and soil temperature to a certain extent,the effect was not significantly different from the overall effect,so these factors were subcritical factors influencing N₂O emissions from wheat fields.These factors do not directly participate in the generation of N₂O but indirectly affect the generation and emis-sion of N₂O by affecting soil microorganisms or interlacing with the key factors.Based on its influence on N₂O emissions from wheat fields under different tillage methods,the four were ranked as soil texture>carbon nitrogen ratio>pH?soil temperature.