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.