实验一 本试验研究不同收获时间对象草青贮发酵品质的影响。象草收获时间分别为8:00、12:00和16:00。在青贮后1、2、3、5、7、14和30天打开青贮罐，测定在青贮发酵过程中发酵品质的动态变化。结果表明16:00试验组的水溶性碳水化合物含量高于8:00和12:00试验组（p>0.05）。青贮前3天，各试验组的pH下降速度较慢。在5-14天期间，8:00试验组的pH和丁酸含量显著低于12:00和16:00试验组（p<0.05）；乳酸含量和乳酸/乙酸（LA/AA）显著高于12:00和16:00试验组（p<0.05）。8:00试验组的氨态氮/总氮（AN/TN）和总挥发性脂肪酸含量（Total VFAs）在7-14天间显著低于12:00和16:00试验组（p<0.05）。在青贮的第30天，8:00试验组的乳酸含量显著高于12:00和16:00试验组，丁酸含量显著低于12:00和16:00试验组（p<0.05）。综合考虑各项指标8:00试验组发酵品质优于其它两处理组。 实验二 本试验研究同一天中不同时间收获对杂交狼尾草青贮发酵品质的影响。杂交狼尾草收获时间分别为8:00、12:00和16:00。在青贮后1、2、3、5、7、14和30天打开青贮罐，测定在青贮发酵过程中发酵品质的动态变化。经对材料草WSC含量的分析得出各试验组收获时DM和WSC含量大小关系为:16:00>12:00>8:00。在青贮的前3天，8:00和12:00试验组的pH下降速度较快，在青贮第2天，8:00和12:00试验组的pH显著低于16:00试验组（p>0.05），乳酸含量显著高于16:00试验组。从青贮的第7开始, 12:00试验组的乳酸含量继续快速增加，pH进一步降低。在青贮的第30天，12:00试验组的pH显著低于8:00和16:00试验组（P<0.05），乳酸含量显著高于（P<0.05）其它两组。在青贮的第5-30天期间12:00试验组的AN/TN含量低于或者显著低于其他两组。综合各项指标12:00试验组发酵品质优于其它两处理。 实验三 本试验研究同一天中不同时间收获对多花黑麦草青贮发酵品质的影响。多花黑麦草收获时间分别为8:00、12:00和16:00。在青贮后0.5、1、1.5、2、3、5、7、14和30天打开青贮罐，测定各项指标。经分析得出各试验组收获时DM和WSC含量大小关系为:16:00>12:00>8:00（p>0.05）。8:00和12:00试验组pH在青贮第1.5天开始快速下降，在第3天，8:00和12:00试验组pH显著低于16:00试验组（P<0.05），乳酸含量显著高于16:00试验组（P<0.05）。随着青贮发酵天数的增加，12:00试验组pH进一步降低，在青贮的第14天，12:00试验组的pH、AN/TN、乙酸含量显著低于8:00和16：00试验组（P<0.05），DM和WSC显著高于其它两组（P<0.05）。到了第30天，12:00试验组的WSC含量高于8:00和16：00试验组（P>0.05），LA/AA、AN/TN、乙酸和总挥发性脂肪酸低于其它两组（P>0.05）。综合各项指标12:00试验组发酵品质优于其它两处理。

Experiment I: The aim of this experiment was to evaluate the effects of different harvested time on fermentation quality of Napier grass silages. There were three harvested time as follows: 8:00, 12:00 and 16:00. The silos were opened after 1, 1, 2, 3, 5, 7, 14 and 30 days of ensiling and the fermentation quality were analyzed. The results showed that the water soluble carbohydrate content of 16:00 treatment was higher than 8:00 and 12:00 treatment (P>0.05). The pH of all treatments decreased slowly during the initial 3 days of ensiling. During 5-14 day,, The pH and butyric acid content of 8:00 treatment were significantly(P<0.05) low than 12:00 and 16:00; and lactic acid content and lactic acid/acetic acid were significantly (P<0.05) higher than 12:00 and 16:00 (P<0.05). The AN/TN and total volatile fatty acids content of 8:00 treatment were significantly lower than other treatments during 7-14 day(P<0.05). The lactic acid content of 8:00 treatment was significantly (P<0.05) low than 12:00 and 16:00, and butyric acid content was significantly (P<0.05) low than 12:00 and 16:00 treatments on the 30th of ensiling. Fermentation quality of 8:00 treatment was better than the treatments of 12:00 and 16:00. Experiment II: The aim of this experiment was to evaluate the effects of different harvested times on fermentation quality of hybrid penisetum silages. There were three harvested times as follows: 8:00, 12:00 and 16:00. The silos were opened after 1, 2, 3, 5, 7, 14, and 30 days of ensiling and fermentation quality were analyzed. The results showed that the order of dry matter and water soluble carbohydrate contents of all treatments were as follows: 16:00> 12:00> 8:00(P>0.05). The pH of 8:00 and 12:00 treatments decreased quickly during the initial 3 days of ensiling. Their pH were significantly (P<0.05) lower than 16:00 treatment and the lactic acid contents were significantly (P<0.05) higher than 16:00 treatment. From the 7th day of ensling, Lactic acid content of 12:00 treatment continued to increase, and the pH kept on decreasing. The pH of 12:00 treatment was significantly (P<0.05) lower than 8:00 and 16:00 treatments, and the lactic acid content of 12:00 was significantly (P<0.05) higher than other treatments on the 30th day of ensling. During 5-30day of ensiling, the AN/TN of 12:00 treatment was lower than or significantly (P<0.05) lower than the others. After 30 days ensiling, the silages fermentation quality of 12:00 treatment was better than the treatments of 8:00 and 16:00. Experiment III: The aim of this experiment was to evaluate the effects of different harvested times on fermentation quality of Italian ryegras silages. There were three different harvested times as follows: 8:00, 12:00 and 16:00. Three silos per treatment were opened after 0.5, 1, 1.5, 2, 3, 5, 7, 14 and 30 days of ensiling and fermentation quality of silages were analyzed. The results showed that the dry matter and water soluble carbohydrate contents of fresh forage at 3 time points were as follows: 16:00> 12:00> 8:00(P>0.05). The pH of 8:00 and 12:00 treatments decreased quickly from the 1.5th day of ensiling, and pH of 8:00 and 12:00 treatments was significantly (P<0.05) lower than 16:00 treatment on 3th day of ensiling, and lactic acid content was significantly (P<0.05) higher than 16:00 treatment. The pH of 12:00 treatment continued to decrease with ensiling, and the pH, AN/TN, acetic acid content of 12:00 treatment was significantly (P<0.05) lower than 8:00 and 16:00 treatments; contents of DM and WSC was significantly (P<0.05) higher than other treatments on the 14th day of ensiling. On the 30th of ensiling, the WSC content of 12:00 treatment was higher than 8:00 and 16:00 treatments (P>0.05), and AN/TN, LA/AA, acetic acid and total VFAs contents was lower than other treatment (P>0.05). The above experiments suggested that fermentation quality of 12:00 was better than 8:00 and 16:00.