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【目的】研究模拟生物炭添加对土壤冻融过程中二氧化碳(CO_2)、甲烷(CH_4)和氧化亚氮(N_2O)排放的影响,为冻融期土壤温室气体的减排提供参考。【方法】以伊犁河谷典型农田为研究对象,野外采集原状土柱,并在室内模拟不同幅度的冻融过程(+5℃、-5℃~+5℃和-10℃~+10℃),探求冻融过程中土壤CO_2、CH_4和N_2O排放对生物炭添加(0、20和40 t/hm~2)的响应特征。【结果】与不添加生物炭的处理相比,添加生物炭会使冻融过程中的土壤CO_2排放量提高1.1~1.4倍,但该影响远小于冻融作用对土壤CO_2排放的促进作用(为CK的1.5~3.2倍);虽然冻融作用未显著(P>0.05)影响土壤CH_4的累积排放量,但生物炭的添加显著(P<0.05)促进了45.5%~81.8%的CH_4吸收量;冻融作用使土壤N_2O的累积排放量提高了1.3~3.0倍,生物炭降低了冻融过程中10.2%~30.9%的土壤N_2O排放量,但在多数情况下这种减小并不显著(P>0.05)。【结论】模拟生物炭添加会增加土壤冻融过程中CO_2的排放,也会促进CH_4的吸收和N_2O的减排。
【Objective】 The objective of this study was to investigate the effects of simulated biochar on carbon dioxide (CO_2), methane (CH_4) and nitrous oxide (N_2O) emissions during freezing and thawing so as to provide reference for greenhouse gas emission reduction during freezing and thawing periods. 【Method】 The typical farmland in Ili Valley was taken as the research object. The undisturbed soil column was collected in the field and the freeze-thaw cycles (+5 ℃, -5 ℃ ~ + 5 ℃ and -10 ℃ ~ + 10 ℃) The response characteristics of soil CO2, CH4 and N2O emissions to biochar addition (0, 20 and 40 t / hm ~ 2) during freezing and thawing were investigated. 【Result】 Compared with no biochar treatment, biochar addition increased soil CO 2 emissions by 1.1-1.4 times during freezing and thawing process, but the effect was less than that of freeze-thaw treatment on soil CO 2 emission ( (1.5 ~ 3.2 times of CK). Although the effect of freezing and thawing was not significant (P> 0.05) on the cumulative CH_4 emissions, the biochar addition significantly (P <0.05) promoted the uptake of CH_4 by 45.5% ~ 81.8% The freeze-thaw effect increased the cumulative N 2 O emissions by 1.3-3.0 times and the biochar decreased by 10.2-30.9% soil N 2 O during freeze-thaw cycles, but this decrease was not significant in most cases (P > 0.05). 【Conclusion】 Simulated biochar addition can increase CO 2 emission during soil freezing and thawing, and also promote the absorption of CH 4 and the emission of N 2 O.