Effects of Methane Fermentation on Seed Survival of Broad-Leaved Dock （Rumexobtusifolius L.） with Dairy Manure

To clarify the effect of exposure to methane fermentation on the survival of seeds of Rumexobtusifolius L. contained in dairy slurry, the percentage of seed germination was observed after the mesophilic （35 ℃） and thermophilic （55 ℃） methane fermentation. The number of survival seed was 0% at 55 ℃, 81.6% at 35 ℃ from methane fermentation, and 0% at 55℃, 75.5% at 35 ℃ after heat treatment. The survival rate of the seeds in methane fermentation was similar to heat treatment at 35 ℃. However, in the investigation of seed status, the number of primary and secondary dormant seeds was higher than after heat treatment. This result suggests that since Rumexobtusifolius L. seeds survive in dormant state in mesophilic methane fermentation, the usage of manure as fertilizer need to be considered.