Abstract
Italian ryegrass containing large amounts of nitrate was used for the six experiments as silage material. The material grasses of experiments 1, 2 and 3 were not wilted and ensiled immediately after harvesting. The material grasses of experiments 4, 5 and 6 were wilted in the field for 3 or 4 days. In each of the six experiments, ensilage temperature was controlled at 15℃, 28℃ and 35℃. The effect of the ensilage temperature on the disappearance of nitrate during ensilage was investigated. 1. It was clearly observed that nitrate contents of the silages were more markedly effected by ensilage temperature in the unwilted silages of experiments 1-3 than in the wilted silages of experiments 4-6. In the unwilted silages, large amounts of nitrate remained in the silages at 15℃ and considerable amounts of nitrate disappeared in the silages at 35℃. The silage of 28℃ showed the same trend as in the silage at 35℃. There was, however, one case where large amounts of nitrate remained in the silages. In the wilted silages, the decrease in nitrate contents was not different in three temperature levels. About 31% to 62% of nitrate contents disappeared. There was, however, one case where nitrate contents in the silages extremely remained at 15℃ and considerably disappeared at 28℃. 2. The difference in the effects of ensilage temperature was more clearly observed in the unwilted silages than in the wilted silages. The silages prepared at 15℃ were of very high quality with large amounts of lactic acid, little acetic acid and little VBN. Moreover, butyric acid was not formed in these silages. The quality of the silages at 28℃ and 35℃ were slightly poorer than that of the silage at 15℃. In the wilted silages, the quality of silages became good or middle grade without regard to the ensilage temperature.
