冀西北坝上地区豆禾混播草地建植第三年草地生产力变化研究

为持续研究冀西北坝上地区豆禾混播对草地产草量及其品质的影响，本试验在国家牧草产业技术体系张家口综合试验站选择建植3年的豆禾同行混播草地，测定其产量和品质。结果表明：紫花苜蓿＋无芒雀麦＋垂穗披碱草(MWP)按豆禾比3∶7混播时，年干草产量最高，达9 612.52 kg·hm^-2，较单播紫花苜蓿提高了11.40%，较单播禾草提高了56.64%~61.80%；豆禾混播以MWP3∶7,MW5∶5组合CP、CF含量最高，MW3∶7、MWP3∶7酸性洗涤纤维(ADF)和中性洗涤纤维(NDF)含量最低，均与单播禾草之间差异显著；且MW3∶7第1茬、MWP3∶7第2茬牧草相对饲喂价值(RFV)与相对牧草品质(RFQ)显著高于其他混播处理及单播禾草。综上所述，豆科与禾本科在混播比例为3∶7,5∶5时产量与品质显著提升，以紫花苜蓿＋无芒雀麦组合与紫花苜蓿＋无芒雀麦＋垂穗披碱草组合同行混播效果较好。

Study on the Changes of Grassland Productivity in the Third Year of Mixed Sowing in Bashang Area of Northwest of Hebei

In order to continuously study the effects of legume-grass mixtures on hay yield and forage quality in Bashang Area of Northwest Hebei Province,the legume-grass mixtures sowing grassland setup sowed for 3 years in Zhangjiakou comprehensive test station of national forage industry technology system was selected,and its yield and quality were measured. The results showed that:in the third year of mixed sowing,the annual hay yield of Medicago sativa+Bromus inermis+Elymus nutans (MWP) according to the legume-to-grass ratio of 3:7 was the highest,up to 9 612.52 kg·hm^-2,which was 11.40% higher than that of single sowing in the same year. Compared with the grass of single sowing,it was significantly increased by 56.64% to 61.80%;and the CP and CF contents of mixed sowing of legume and grass (3:7) of MWP and MW (5:5)were the highest,while the contents of acid detergent fiber (ADF) and neutral detergent fiber (NDF) of MW3:7 and MWP3:7 were the lowest,which were significantly different from those of the grass of single sowing. The relative feeding value (RFV) and relative forage quality (RFQ) of the first cutting of MW3:7 and the second crops of MWP3:7 were significantly higher than those of other mixed sowing and single sowing. To sum up,in the third year of mixed sowing,the yields and quality of legumes and gramineae were significantly improved when the mixed sowing ratios were 3:7 and 5:5. The mixed sowing of Medicago sativa+Bromus inermis as well as Medicago sativa+Bromus inermis+Elymus nutans were better.