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冻结能够增加土壤二氧化碳和氧化亚氮排放以及活性碳和氮的释放.然而,目前很少报道土壤冻结处理后两种温室气体排放变化的差异以及与土壤属性的关联性.论文研究了土壤冻结强度和冻结时间对中国东北成熟阔叶红松混交林和临近的次生白桦林土壤二氧化碳(CO2)和氧化亚氮(N2O)、氮素净矿化量、微生物量和可浸提的碳和氮含量的影响.两种林地土壤具有不同的微生物量和容重.取上述两种温带林地0~5和5~10 cm原状土柱,分别进行?8,?18和?80℃冻结处理10和145 d,然后各自在10℃下融化培养21 d.未进行冻结前处理的原状土柱样品,10℃培养21 d为对照.融化后土壤N2O和CO2排放量随林分类型、土壤深度和冷冻处理而发生变化,该差异归因于冻结后所致的土壤充水孔隙度(WFPS)和物质有效性变化.土壤湿度大约为80%WFPS时,融化期森林土壤N2O排放量最大,而森林土壤CO2排放量却随土壤湿度增加而显著地增加.冻结处理后,土壤溶解性有机碳含量和CO2排放量均随冻结时间延长而增加,这与土壤微生物碳含量降低相一致;冻结温度显著影响森林土壤氮素净矿化量和净氨化量以及氧化亚氮排放量.土壤N2O排放量与土壤p H和容重呈显著的负相关关系,却与土壤K2SO4浸提的硝态氮含量和氮素净氨化量呈显著的正相关关系.土壤CO2排放量与土壤氮素净矿化量和净氨化量呈显著的正相关关系.因此,基于较宽范围的冻结温度和冻结时间的观测结果,融化后土壤N2O和CO2排放量主要依赖于冻结处理后氮素净矿化量、释放的物质有效性以及有关通气性的土壤属性变化.
Freezing can increase the release of soil carbon dioxide and nitrous oxide as well as the release of activated carbon and nitrogen.However, it is seldom reported the difference of the change of the two greenhouse gases after soil freezing treatment and the correlation with the soil properties.This paper studied the soil freezing strength And freezing time on soil carbon dioxide (CO2) and nitrous oxide (N2O), net nitrogen mineralization, microbial biomass and extractable carbon and nitrogen in the mixed broad-leaved Korean pine mixed forest and the adjacent secondary birch forest in northeastern China .The two kinds of woodland soils had different microbial biomass and bulk density.The soil samples from 0 ~ 5 and 5 ~ 10 cm undisturbed soil samples of the above two kinds of temperate forests were frozen at 8, 18 and 80 ℃ for 10 and 145 days respectively, And then each was thawed at 10 ° C for 21 days.The undisturbed soil column sample was pretreated with frozen soil for 21 d at 10 ° C as a control.The emissions of N2O and CO2 from the thawed soil varied with stand type, soil depth and freezing treatment (WFPS) and material availability change after freezing.When the soil moisture was about 80% WFPS, the N2O emission of forest soil in the melting period was the largest, while the soil CO2 emission But with Soil moisture increased significantly and significantly increased after freezing treatment, soil dissolved organic carbon content and CO2 emissions increased with the freezing time, which is consistent with the reduction of soil microbial carbon content; freezing temperature significantly affect the forest soil nitrogen net mine The amount of nitrogen and nitrogen, the amount of nitrification and the amount of nitrous oxide emissions.The soil N2O emissions and soil p H and bulk density was a significant negative correlation, but with the soil K2SO4 extract of nitrate nitrogen and nitrogen was ammoniated There was a significant positive correlation between soil CO2 emissions and net nitrogen mineralization and net ammoniation.According to the results of a wide range of freezing temperature and freezing time observation, And CO2 emissions mainly depend on the amount of nitrogen mineralization after freezing, the effectiveness of the material released, and the change of soil attributes related to aeration.