Effects Of Different Cutting Intensities On Greenhouse Gas Flux In Grassland Ecosystem In Northern Agro-pastoral Ecotone

For nearly half a century,with the dramatic increase in the use of fossil fuels and more frequent human activities,the global ecological environment has changed,such as climate warming.The significant increase in greenhouse gas content is widely recognized as the main cause of global warming.Grassland ecosystems account for 20% of terrestrial ecosystems,and their contribution to global climate change cannot be ignored.However,studies on the effects of management utilization on greenhouse gas fluxes in grassland ecosystems have not been systematically carried out,especially in areas where grassland distribution in the agro-pastoral zone is rare.Therefore,in order to explore the response of greenhouse gas fluxes in different farming and pastoral ecotones to different cutting strengths,in the grassland of agriculture and animal husbandry in the north of Shanxi Province,a randomized block design was adopted,and four cutting forces were set(not castrated,Experiments with 10 cm of stubble,5 cm of stubble and 2 cm of stubble,for two consecutive years of measurement of the flux of three major greenhouse gases?CO₂,CH₄ and N₂O?during the growing season?static box-gas chromatography?,Combined with the changes of plant community characteristics and soil physical and chemical characteristics,the main factors affecting the greenhouse gas flux in the agro-pastoral ecotone are analyzed.The research results are as follows:1 Castration had no significant effect on the greenhouse gas flux and its seasonal dynamics in the grassland ecosystem in the northern Agro-pastoral ecotone.It may be due to the short test time,and the impact of castration on the grassland ecosystem is likely to take a certain number of years to be highlighted.2 Castration treatment had no significant effect on the CO₂ emission and N₂ O growth season average fluxes in the two growing seasons,However,the castration treatment of 2 cm and 10 cm significantly increased the CH₄ uptake in the grassland ecosystem during the 2018 growing season?P<0.05?,with an increase of 303% and 242%,respectively.There was no significant effect on CH₄ flux during the 2017 growing season?P>0.05?.3 Regression analysis showed that the aboveground biomass had no significant effect on the three greenhouse gas fluxes?P>0.05?,and there was no significant correlation between underground biomass and CO₂ emissions and CH₄ flux?P>0.05?.Significantly affected N₂ O flux?non-linear correlation,P<0.05?.Microbial biomass carbon?MBC?and microbial biomass nitrogen?MBN?were positively correlated with CO₂ emissions?P<0.05?,but had no significant effect on CH₄ and N₂ O fluxes?P>0.05?.MBC/MBN and N₂ O fluxes were exponentially correlated?P<0.05?,but had no significant effect on CO₂ emissions and CH₄ flux?P>0.05?.Soil temperature had no significant effect on CO₂ emission and CH₄ flux,and N₂ O emission increased with soil temperature?P<0.05?.Soil moisture had no significant effect on CH₄ flux?P>0.05?,CO₂ emission and N₂ O flux.There was a significant negative correlation with soil moisture content?P<0.05?.