| 陈哲,韩瑞芸,杨世琦,张爱平,张晴雯,米兆荣,王永生,杨正礼.东北季节性冻融农田土壤CO2、CH4、N2O通量特征研究[J].农业环境科学学报,2016,35(2):387-395. |
| 东北季节性冻融农田土壤CO2、CH4、N2O通量特征研究 |
| Fluxes of CO2, CH4 and N2O from seasonal freeze-thaw arable soils in Northeast China |
| 投稿时间：2015-09-23 |
| DOI：10.11654/jaes.2016.02.025 |
| 中文关键词: 黑土 非生长季 温室气体 冻融交替 雪被 源汇 净温室效应 |
| 英文关键词: black soil non-growing season greenhouse gas freeze-thaw cycle snow cover source and sink net greenhouse effect |
| 基金项目:国家水体污染控制与治理科技重大专项(2014ZX07201-009) |
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| 中文摘要: |
| 为了评估季节性冻融交替对土壤温室气体排放的影响,采用静态暗箱-气相色谱法,监测了东北松嫩平原两种典型农田生态系统(稻田和玉米田)非生长季土壤CO2、CH4和N2O通量变化。研究表明:三种温室气体排放在土壤冻结期、覆雪期、融雪期和解冻期具有明显的季节动态特征。冻结期和融雪期对温室气体排放贡献最大,这两个时期内稻田和玉米田CO2排放量分别占非生长季总累积排放量的74.9%和68.6%,稻田CH4排放占非生长季总排放的95.7%,尽管玉米田土壤CH4以吸收为主,但在融雪过程中存在明显释放峰;短暂的融雪期内N2O呈集中爆发性释放,稻田和玉米田N2O通量峰值分别是冻结前的40倍和99倍,排放量占到总累积排放量的73.9%和80.7%,覆雪期土壤CH4和N2O存在弱的吸收。另外,土壤温室气体排放存在土地利用方式间的差异,表现在稻田土壤比玉米田(非生长季)具有更高的温室气体排放潜力。稻田土壤CO2、CH4和N2O累积排放量均高于玉米田,表现为净排放(源),而玉米田土壤CH4通量表现为净吸收(汇);稻田土壤CO2和CH4平均排放速率显著高于玉米田;除覆雪期外,其他时期内三种温室气体平均通量在两类农田之间也存在显著差异。总之,在评价季节性冻土区温室气体排放时需要重视土壤冻结和融化过程,同时需要考虑不同土地利用方式间的差异。 |
| 英文摘要: |
| We monitored the dynamics of soil CO2, CH4 and N2O fluxes of two typical agricultural ecosystems(paddy/maize field) in Songnen Plain using static opaque chamber-gas chromatograph method. The greenhouse gases(GHG) emissions showed obvious seasonal pattern, which could be divided into four periods——freezing, snow cover, snow melting, and frost free. The freezing and snow melting periods were critical for greenhouse gases(GHG) emissions. During these two periods, CO2 emissions from paddy and maize fields accounted for 74.9% and 68.6% of the total cumulative CO2 emissions, respectively. The CH4 emissions from paddy field amounted to 95.7% of the total CH4 emissions. In the maize field, CH4 showed absorption during the experimental period. However, it had large releases during snow melting. Soil N2O emissions showed intensive explosive release during the short snow melting period. The peak of N2O flux from paddy and maize fields was respectively 40 times and 99 times higher than that before soil freezing. The cumulative emissions of N2O from two farmlands accounted for 73.9% and 80.4% of the total N2O emissions, respectively. During the snow covering period, CH4 and N2O were weakly absorbed. In addition, different land uses showed different patterns of GHG emissions. Paddy had higher potential GHG emissions than maize field did. Taken together, CO2, CH4 and N2O fluxes from paddy field were net emissions(source), and the total cumulative emission was higher than that of maize field. The average emission rates of CO2 and CH4 were significantly higher in paddy than in maize field. However, CH4 flux of maize field was net absorption(sink). The average GHG flux was significantly different between these two types of farmland. In conclusion, GHG emissions during soil freezing, thawing and snow melting periods should be taken into account when evaluating the GHG emissions in seasonal frozen regions. GHG emissions under different land uses are different. |
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