Soil Greenhouse Gas Emissions And Their Influencing Factors In Wetlands And Farmlands

Wetlands are important soil carbon pools in terrestrial ecosystems.However,with the development of human beings,many wetlands have been converted into farmland,which has caused the natural environment and even humans to lose many environmental benefits,such as the feedback of wetlands and farmland to global warming.And their contribution to greenhouse gas emissions.Therefore,this article focuses on the Tumen River basin,an important international river in the middle temperate zone,and uses the portable greenhouse gas monitor in the field to carry out four types of useful land types:natural wetlands,restored wetlands,rice fields,and dry fields.Research on the status of gas emissions and its influencing factors,the conclusions are as follows:(1)The difference between the average cumulative emissions of wetlands and farmland is significant,and natural wetlands in this area become the environmental system with the smallest cumulative emissions.The average cumulative emission of CO2 in natural wetlands is 391.08g m2,and the average cumulative emission of CH4 is 47.62g m-2;the average cumulative emission of recovered wetlands is 1002.22g m-2,and the average cumulative emission of CH4 is 1129.06 g m-2;average cumulative CO2 emissions from rice fields is 650.82g m-2 and average cumulative CH4 emissions are 35.33g m-2;average cumulative CO2 emissions from dry fields are 2469.93g m-2 and average cumulative CH4 emissions are-0.14g m-2;(2)Wetlands and farmland have different factors affecting greenhouse gas emissions.Soil temperature and electrical conductivity are the most obvious in wetlands,while farmland is significantly affected by soil water content,electrical conductivity and nitrogen.The main factors in natural wetlands are concentrated in soil moisture content,soil temperature,and soil conductivity,especially the effects of soil conductivity and moisture content on CO2 emissions.Significantly,the effect of soil temperature on CH4 is significant;the restoration of wetland soil temperature and electrical conductivity are the key factors affecting the two kinds of gas emissions.Among them,soil temperature has a very significant positive correlation with CO2 emissions,while soil electrical conductivity significantly affects CH4 Emissions;the most important factors affecting CO2 and CH4 emissions in rice fields are still soil temperature,water content,and electrical conductivity,but the main factors affecting gas emissions are different;the factors affecting greenhouse gas emissions in dry fields are mainly concentrated in soil water content,Electrical conductivity,and nitrate nitrogen,of which soil moisture,electrical conductivity,and nitrate nitrogen have the greatest impact on CO2 emissions,but there are differences in the impact on CH4 emissions;(3)In terms of contribution to global warming,natural wetlands have become the smallest ecological environment system.Therefore,the protection of wetlands is not only to maintain the strong ecological functions of the wetlands themselves,but also to adjust the micro-topographic climate,although the restoration of wetlands will reduce the short-term The contribution of the row is not significant,but the trend of temperature increase is to decrease the range.From the 100-year and 500-year scales,the contribution of the warming of wetland restoration has decreased significantly by 54%and 73%compared with the inter-decade level..The contribution of paddy field warming in farmland decreased significantly,but the results of different management methods caused huge differences.The dryland maintained a small increase in warming contribution,and the cumulative base of the field of soybean cultivation was high.Therefore,in combination with this study,proper management of water content input,reduction of paddy field irrigation,and intermittent irrigation can be adopted.At the same time,upland fields can also adopt appropriate water content to nourish the greenhouse gas emissions of CO2 and CH4.Minimize human impacts on natural wetlands,allow them to develop naturally,and restore wetlands(reed wetlands)if they can artificially interfere with their vegetation species or reduce gas emissions.