The Effects Of Different Improvement Measures On Degraded Leymus Chinensis Grassland Communities And Greenhouse Gas Flux

The increasing carbon-bearing greenhouse gases such as CO₂ and CH₄ have caused global warming,while grasslands that are more sensitive to climate change are continuing to degrade.In the face of grassland degradation,humans have developed a series of improvement measures.In order to further explore the impact of the improved degraded grassland on the global climate,this study was conducted in 2016-2017,Inner Mongolia University Grassland Ecology Research Base,Maodeng Ranch,Xilinhot,Inner Mongolia,China.the degraded Leymus chinensis grassland treated by shallow tillage and cutting root was taken as the research object.The static box method-Picarro was used to measure the characteristics of greenhouse gas flux,and the aboveground biomass and underground biomass were obtained during the same period.Data such as soil temperature and water content draw the following conclusions:1.Shallow ploughing and root cutting could increase above-ground biomass and Leymus chinensis population biomass in different degrees,and had obvious effect on the restoration of Leymus chinensis population structure.2.The daily and growing season dynamics of soil respiration under different improvement measures showed that shallow ploughing and root cutting did not change the CO₂ emission of typical steppe soil,but there was no significant difference between them and CK?P>0.05?.3.The respiration and growth season dynamics of ecosystem under different improvement measures showed that shallow ploughing and root cutting did not change the CO₂ emission of typical grassland ecosystem,and the difference between them was significant?P<0.05?.But there was no significant difference between the two groups and CK?P>0.05?.4.The diurnal dynamics of net gas exchange showed that shallow tillage and root-cutting treatment but did not change the nature of CO₂ sink in typical grassland,and there was no significant difference among the three treatments?P>0.05?.5.Generally speaking,soil temperature is the main factor affecting CO₂emission from typical grassland.However,in the arid and rainless environment,soil moisture becomes the limiting factor affecting CO₂ emission from typical grassland.6.Diurnal and seasonal dynamics of CH₄ uptake showed that shallow tillage and root-cutting treatment promoted and inhibited the CH₄ uptake capacity of ecosystem respectively,and there were significant differences among different treatments?P<0.05?,but did not change the nature of CH₄ sink in typical grassland.7.In semi-arid typical grassland,soil moisture content is the main factor affecting the absorption of CH₄ gas by ecosystems.