The Influence Of Cutting Height To The Output And Quality Of Pennisetum Purpureum Schum TLG2

This study is about the biological production of Pennisetum purpureum schum TLG2, the situation of the nutritional value and the artificial rumen degradability. One best cutting height is expected to be found out. So the biological production, nutrition level and the degradation utilization rate can all reach a high level. That can advance the value of grazing, and provide some scientific support for application and spread of Pennisetum purpureum schum TLG2 in Fujian.This study includes three parts totally: 1)The study of biological production at different cutting height of Pennisetum purpureum schum TLG2; 2) Study on the nutrient value of different cutting height of Pennisetum purpureum schum TLG2. 3)Study on the trend of artificial ruminal degradability in vitro of different cutting height of Pennisetum purpureum schum TLG2. The result shows that:Firstly, with Pennisetum purpureum schum TLG2's cutting height increasing, its output of fresh grass went up first and fell slowly behind. The biggest output of fresh grass is the cutting height of 2.7m which reached to 212.90t/hm2 .That is significantly higher than others(P<0.05).And the smallest output of fresh grass is the cutting height of 1.2m which reached to 146.43t/hm2. The former figure compares the latter raises 45.39 percent. The biggest hay yield is the cutting height of 3.7m which reached to 37.80t/hm2.There were not significant difference between the treatment group 2.7m and 3.2m.Other treatment groups's hay yield was increasing significantly follow the cutting height increasing.With the elongation of the growth stage, its output of hay yield,content of DM and stem leave ratio were increasing.Secondly, the nutrient value of the Pennisetum purpureum schum TLG2 was varied from different cutting height. With its cutting height increasing, its CP content was gradually reduced.And the cutting height of 1.2m had the highest CP content which reached to 14.80%. The 3.7m treatment had the lowest CP content which only 6.67%.With the cutting height increasing,the ASH content reduced significantly(P<0.05),and the ADL content increased significantly(P<0.05).The smallest ADL content is the 1.2m treatment which only 2.37%,and the biggest is the 3.7m treatment which reached to 8.13%.The NDF and ADF content were increased gradually with the cutting height increasing.Thirdly, the highest DMD for 24h degradation In vitro is the 1.2m treatment which reached to 56.52%, and it heightened 25.10% compare with the 3.7m treatment which had the lowest DMD.The DMD of all treatment reduced significantly with the cutting height increasing.The treatment 1.2m had the highest DNDF and DADF which reached to 51.95% and 45.74%.And the treatment 3.7m had the lowest DNDF and DADF which reached to 44.98% and 38.07%.With the cutting height increasing, the DNDF and DADF both decreased.Fourthly, the highest aggregate digestible dry matter in unit area is the 2.7m treatment which reached to 14.00t/hm2,2.2m treatment followed.The lowest one is the 1.2m treatment which only 9.90t/hm2.The highest CP content in unit area is the 2.2m treatment which reached to 3.80t/hm2,2.7m treatment followed.The lowest one is the 3.7m treatment which only 2.53t/hm2. That indicated the best cutting height of Pennisetum purpureum schum TLG2 was 2.2m to 2.7m.