Effects Of Litter Removal On Soil Greenhouse Gas Flux In Pinus Tabulaeformis Plantation Of Daqing Mountains

Global warming is an indisputable fact.Litter decomposition is a key link in the carbon cycle of forest ecosystem.To study the effects of litter on soil greenhouse gas flux is helpful to clarify the important role of forest soil carbon cycle and the response degree of soil respiration to litter decomposition.Inner Mongolia Daqing Mountains Pinus tabulaeformis plantation is located in the middle of Yinshan mountain,which has great ecological and social benefits.In this study,two treatments of No Litter（NL）and Control Check（CK）were set.In the 2020 and 2021 growing season,static box-gas chromatography was used to measure greenhouse gases.At the same time,correlation analysis and linear relationship analysis were carried out combining environmental factors and soil physical and chemical properties.To reveal the effects of litter decomposition on soil greenhouse gas flux in Daqing Mountains Pinus tabulaeformis plantation.The results show that:1.After litter removal,soil temperature increased by 1.4℃and 1.7℃in 2020 and2021,respectively;Soil moisture decreased by 3.6%and 2.4%,respectively.The seasonal variation of soil temperature and humidity under both NL and CK treatments firstly increased and then decreased.The maximum soil temperature appeared in June and July,and the maximum soil moisture in 2021 was slightly earlier than that in 2020.2.After forest litter removal,soil water content,organic carbon,total nitrogen,ammonium nitrogen,nitrate nitrogen and alkali-hydrolyzed nitrogen decreased by 11.03%,41.04%,23.42%,48.54%,60.62%and 42.19%in 0～10 cm soil layer,respectively.In10～20 cm soil layer,the soil decreased by 8.28%,16.99%,15.71%,33.33%,29.03%and34.74%,respectively.3.Litter removal significantly reduced soil CO₂flux,which decreased by 28.53%and20.83%in 2020 and 2021.The average CO₂flux in the growing season increased first and then decreased.There are obvious diurnal and diurnal differences,the variation range of daytime and night is different,and the peak time of CO₂flux is different.Litter removal significantly increased CH₄flux by 15.96%and 13.27%in 2020 and 2021.The variation trend of monthly average CH₄flux in two growing seasons was slightly different.The order of diurnal variation of soil CH₄flux in different months was July>September>May>June>August.Litter removal significantly reduced soil N₂O flux by 63.39%and36.11%in 2020 and 2021.The order of diurnal variation amplitude of soil N₂O flux in different months of the growing season was as follows:May>August>July>June>September.4.The soil GHG warming potential of Pinus tabulaeformis plantation in 2020 and2021 is as follows:Control Check treatment>No Litter treatment,the total GWP of Daqing Mountains Pinus tabulaeformis plantation in 2020 was 1185.24(g·m^-2)under Control Check treatment,and 887.36(g·m^-2)under No Litter treatment,both of which were lower than the total GWP of 2021.5.After litter removal,soil respiration temperature sensitivity decreased,and Q₁₀values of NL and CK were 2.23 and 2.84,respectively.