长期不同施肥制度下湖南红壤晚稻田CH4的排放

选取湖南双季稻田长期不同施肥制度为研究对象,采用静态箱-气相色谱法对晚稻稻田甲烷排放进行观测.研究结果表明,不同施肥制度下的晚稻稻田甲烷排放的季节变化具有一定的规律,晚稻生育期内CH4的排放速率呈先升高后降低的变化趋势.施入秸秆的处理CH4平均排放通量和累积排放通量大于单施化肥的处理;单施化肥的各处理中由于养分缺失情况的不同,CH4平均排放通量和累积排放量具有一定的差异.秸秆区CH4平均排放通量和累积排放量都较大,全量化肥养分施肥区次之,偏施养分和无肥区较小.同时还研究了长期不同施肥制度条件下各环境因素包括土壤温度、灌溉水层深度和土壤Eh,对CH4排放的影响.结果表明,不同的施肥处理,晚稻田CH4排放的季节变化和土壤Eh呈显著负相关,与土壤温度呈显著正相关,与水层深度相关不明显.

Methane emission from late rice fields in Hunan red soil under different long- term fertilizing systems

By using the method of static chamber-gas chromatographic techniques, methane emission flux from late rice fields were studied under different long-term fertilizing systems. The results showed that, methane emission from late rice fields from different fertilizing systems differed with seasonal variation, and represented an increasing at the beginning and declining later on. Methane emission flux and accumulation emission flux of straw manure treatment was significantly higher than that of all other treatments; Methane emission flux and accumulation emission flux differed between different nutrients deficiencies. Methane emission flux and accumulation emission flux of straw manure treatment was higher than that of inorganic total nutrient treatment. Methane accumulation emission fluxes were the lowest under non- or partial- fertilizer treatments. The environmental factors of different long-term fertilizing systems affecting methane emission from late rice fields were discussed, including soil temperature, water depth and soil Eh. Under different long-term fertilizing systems, there was a significantly positive correlation between CH4 emission flux and soil temperature and a significantly negative correlation between CH4 flux and soil Eh. No significant correlation was found between CH4 flux and water depth.