土壤温度和氧化还原特性对冷浸田CH_4排放的影响

Effects of Temperature and Soil Reducing Matter on CH_4 Flux from Cold Waterlogged Paddy Field

采用静态箱-气相色谱法对普通稻田(GPF)、撂荒复耕冷浸田(RCWPF)和冷浸田(CWPF)的CH4排放进行田间原位观测。结果表明,在水稻生长期,3种稻田CH4排放通量的季节变化峰值均出现在水稻分蘖盛期,且都只有一个典型的排放锋,且GPF的CH4排放通量平均值极显著小于RCWPF和CWPF。3种稻田CH4排放通量和温度均呈正相关,且RCWPF和CWPF的CH4排放通量与大气温度和5 cm土壤温度的相关性弱于GPF。土壤氧化还原特性影响CH4排放通量,GPF的CH4排放通量与土壤还原性物质总量、活性还原性物质含量、Fe2+含量及活性有机还原性物质含量的相关系数分别为0.586、0.681、0.689和0.642;除氧化还原电位外,RCWPF和CWPF的CH4排放通量与其他土壤氧化还原特性指标均呈负相关,相关性不显著。土壤还原性强是冷浸田CH4排放通量高的原因之一。

The field experiment was conducted to evaluate CH4 emissions from general paddy field （GPF）,abandoned and resumed cold waterlogged paddy field （RCWPF） and general cold waterlogged paddy （CWPF） with static-chamber and a modified gas chromatograph （Agilent）.The results showed that there was only one CH4 emission peak during rice growing season and it appeared at fully tillering stage.The CH4 emission flux of GPF had a significant difference to GPF and RCWPF.Correlation analysis showed that CH4 emissions was significantly correlated with temperature,and the relevance of CH4 emission flux and temperature of RCWPF.CWPF were weak than that of GPF.The soil oxidation-reduction status affected the CH4 emission flux from the three paddy fields.The correlation ralues between the total reducing matter,active reducing matter,Fe2＋,active organic reducing matter and fluxes of methane emission were 0.586,0.681,0.689 and 0.642,respectively.The strong reducing property of soil in cold waterlogged paddy field was one of the reasons for high CH4 emissions flux.