Abstract
Italian ryegrass containing large amounts of nitrate was ensiled in laboratory silos at three moisture levels adjusted by pre-wilting. Effect of these moisture levels on the disappearance of nitrate was investigated. At each moisture level, the following ensiling treatments were applied ; (1) the material was packed heavily and lightly (Expt.II), (2) the material was chopped into 1cm and 5cm in lengths (Expt.III). The silos were kept at 28℃ in the incubator and opened at 3, 7, 15 and 50 days after ensiling. The results obtained were as follows: 1. At high and medium moisture levels, the nitrate contents considerably decreased with advancing period of ensiling. In low moisture silage, the nitrate contents changed little during ensilage process. These silages were chracterized by a high pH value but, large amounts of butyric acid was found at high moisture levels. 2. The high moisture silages were different in the nitrate disappearances and qualities between the silages of the heavy pack and those of the light one in Expt.II, but the qualities of both silages were poor and the nitrate disappearances of these silages were high. There were no marked differences in the nitrate disappearances and qualities between the silages chopped into 1cm and 5cm in lengths, at each moisture level in Expt.III. 3. The high moisture silages were poor in quality and the rate of nitrate disappearance were from 80.1 to 100%. At medium and low moisture levels, the quality of these silages were slightly better than that of the high moisture silages. But there were differences in the rate of nitrate disappearances between the medium and the low moisture level. The rate of nitrate disappearrance was from 91.5 to 98.0% in the silages of medium moisture, and from 4.2 to 30.0% in the silages of low moisture.
