冬季土地管理对稻季CH4产生、氧化和排放的影响

通过室内培养和田间试验测定了冬季休闲、种麦和淹水处理水稻生长期CH4的产生潜力、氧化潜力及其排放通量，以探讨冬季土地管理对后续稻季CH4产生、氧化和排放的影响。结果表明：休闲与种麦处理间CH4产生潜力无显著差异（P〉0．05），但2者均显著低于淹水处理（P〈0．05）；各处理间CH4氧化潜力无显著差异（P〉0．05），土壤中NH4^＋-N含量可能是较冬季土地管理更为重要的影响CH4氧化潜力的因素；休闲处理CH4平均排放通量显著高于种麦处理（P〈0．05），但2者均显著低于淹水处理（P〈0．05）。冬季持续淹水稻田CH4产生潜力显著高于冬季排水稻田是其CH4排放量远高于冬季排水稻田的原因。冬季土地管理对稻季CH4排放的影响主要受CH4产生潜力而非CH4氧化潜力的限制。

Effects of Land Management in Winter on Production, Oxidation and Emission of CH4 During the Rice-Growing Season.

To study effects of land management in winter on production, oxidation, and emission of CH4 from the paddy field during the following rice-growing season, indoor incubation and field experiments were carried out to measure CH4 production potential, CH4 oxidation potential, and CH4 flux in Treatments DF （drained fallow） , DW （drained with wheat planting）, and FF （flooded fallow）. Results show that no significant difference in CH4 production potential was observed between Treatments DF and DW （P〉0. 05）, but both were significantly lower than in Treatment FF （P〈0. 05）. No significant difference in CH4 oxidation potentials was observed among the three treatments （P〉0. 05）. Compared with the effects of land management in winter on CH4 oxidation potential, the effect of soil NH4^＋-N content during the rice-growing season was more important. The mean CH4 flux was much higher in Treatment DF than in Treatment DW （P〈0. 05）, but both were significantly lower than in Treatment FF （ P〈0. 05 ）. The significantly higher CH4 production potential in Treatment FF than in Treatment DF was the reason why the CH4 flux in Treatment FF was much higher. The effects of land management in winter on CH4 emission during the rice-growing season were mainly affected by CH4 production potential rather than CH4 oxidation potential.