This experiment was carried out to investigated the effects of levels of mineral nitrogen under various cutting systems on the nutritive value and nutrient yields of orchardgrass (Dactylis glomerata L.) during harvested years in 1993-1995. The content...
This experiment was carried out to investigated the effects of levels of mineral nitrogen under various cutting systems on the nutritive value and nutrient yields of orchardgrass (Dactylis glomerata L.) during harvested years in 1993-1995. The contents of crude protein (CP), total digestible nutrients (TDN), relative feed value (RFV) and annual nutrient yields in relatively wet year (1993) were significantly higher than those in the other harvested years, but the tendency of contents of acid detergent fiber (ADF) and neutral detergent fiber (NDF) were against. The contents of CP, TDN, RFV of all cutting frequencies were highest at the last cut, but lowest at the 2nd cut. The annual nutrient yields were highest at the 1 st cut in 3 cuttings, and at the 2nd cut in 4 and 5 cuttings, respectively. Significantly higher contents of CP in all cutting frequencies appeared in according to increase the levels of mineral nitrogen, but the contents of ADF were lower with nitrogen fertilization of 60 kg ha^(-1) cut^(-1) in 4 and 5 cuttings than those in non-fertilized plots. Higher efficiencies of dry matter production (kg DMY kg^(-1) N), crude protein production (kg CPY kg^(-1) N) and total digestible nutrients production (kg TDNY kg^(-1) N) in response to mineral nitrogen fertilization were recorded as 12.9, 1.4 and 7.6 kg at level of 360 kg ha^(-1) in 3 cuttings, 27.3. 2.7 and 16.0 kg at level of 120 kg ha^(-1) in 4 cuttings, 20.5, 2.0 and 12.7 kg at level of 360 k, ha^(-1) in 5 cuttings, respectively. In all treatments, negative correlation between CP and ADF or NDF appeared (P<0.001). Positive correlations were recorded between CP and TDN or RFV. and among TDN and nutrient yields (P<0.01).