Simulated Effects Of Warming On Soil Greenhouse Gas Fluxes In Larix Gmelinii Forest In Daxing’ Anling

In this Larix gmelinii forest in Daxing’anling,Inner Mongolia was used as the research object,and the effects of simulated warming on soil greenhouse gas fluxes and soil physicochemical properties were studied by in-situ observation in the growing season（June-October）of 2020-2021 by using Open Top Chamber（OTC）combined with static box-gas chromatography.The response laws of soil nutrients,soil CO₂,CH₄,N₂O and other three greenhouse gas fluxes to warming and the mechanism of response to climate change were studied,and the results showed that:1.After simulated warming treatment,the air temperature increased by1.07℃and 0.95℃in two years compared with the control.Simulated warming was beneficial to increase soil temperature in 0～20 cm soil layer,but different treatments increased soil temperature differently.Different treatments reduced soil moisture content in 0～20 cm soil layer.2.Warming treatment increased soil p H,soil ammonium nitrogen and nitrate nitrogen content,decreased organic carbon（SOC）and total nitrogen（TN）content.Under the warming and control treatments,there was no significant difference in soil p H between the two years（P>0.05）.Under the warming treatment,the soil p H increased the most in September 2021.Soil organic carbon and soil total nitrogen were signi;ficantly different in August2020（P<0.05）,but not significantly different in other treatments and months.In July 2020,the soil ammonium nitrogen content under warming treatment was significantly different from that under control treatment（P<0.05）,and t he soil nitrate nitrogen content also decreased with the increase of month.3.The soil under two treatments（simulated warming and control）in the growing season of Larix gmelinii forest in 2020 and 2021 showed that warming promoted the emission of soil CO₂and N₂O gas fluxes and promoted the emission of soil CH₄ gas absorption.Air temperature,air humidity,soil temperature and soil moisture were the main limiting factors for the seasonal variation of soil CO₂ flux.4.Under simulated warming and control treatments,soil CO₂ content was negatively correlated with soil p H and ammonium nitrogen（P<0.05）,and positively correlated with nitrate nitrogen（P<0.05）.Under the control treatment,soil CH₄ flux was significantly positively correlated with organic carbon and ammonium nitrogen（P<0.05）.There was no significant correlation between soil N₂O flux and soil chemical properties under warming and control treatments.