冀西北地区错期交叉混播对第3年草地生产力的影响

本研究在无芒雀麦与垂穗披碱草的基础上错期交叉播种紫花苜蓿，以豆禾交叉混播3年草地为研究对象，对第3年草地干草产量和牧草品质进行分析测定，探究不同播期下紫花苜蓿与无芒雀麦、垂穗披碱草交叉混播对草地生产力的影响。结果表明：交叉混播第3年，紫花苜蓿在无芒雀麦播后0 d，30 d，45 d与之交叉混播，年干草产量显著高于其他处理；在垂穗披碱草播后15 d与之交叉混播，年干草产量最高。在无芒雀麦播后30 d内播种紫花苜蓿，与间隔75 d的处理相比，牧草品质得到显著改善。在垂穗披碱草播后0 d，30 d播紫花苜蓿，牧草CP含量显著高于对照；其纤维含量较低、RFV与RFQ较高且与60~75 d处理间差异显著。综合产量与品质优势分析，冀西北地区在禾草播后30 d内播种紫花苜蓿进行交叉混播，可以获得较高的产草量及较好的牧草品质。

Effects of Cross Sowing at Different Times on Grassland Productivity in the Third Year of Planting in Northwest Hebei

In this study,two grasses of Bromus inermis and Elymus nutans,Medicago sativa was vertically sown at different times in the field. The hay yield and forage quality of the mixed sowing grassland in the third year were analyzed and measured by taking the grassland with legume-grass cross sowing for 3 years as the research object,and the effects of cross sowing of Medicago sativa with Bromus inermis and Elymus nutans on grassland productivity under different sowing dates were explored. The results showed that in the third year of cross mixed sowing,the annual hay yield of Medicago sativa which was cross sowed at the 0 d,30 d and 45 d after Bromus inermis sowing was significantly higher than those of other treatments,and the annual hay yield of Medicago sativa which was cross sowed at the 15 d after Elymus nutans sowing was the highest and significantly higher than those of other treatments. When Medicago sativa was sown within 30 d after Bromus inermis sowing,the forage crude protein (CP),crude fat (CF) and relative forage quality were higher,and the contents of acid detergent fiber (ADF) and neutral detergent fiber (NDF) were lower,which was significantly different from the treatment with an interval of 75 d. When Medicago sativa was sown at 0 d and 30 d after Elymus nutans sowing,the CP content of forage was significantly higher than that of the control group,and the NDF content was lower,the relative feeding value and relative feeding quality were higher,and there was a significant difference from the treatment of 60~75 d. The analysis of comprehensive yield and quality advantages showed that high hay yield and forage quality can be obtained by cross mixed sowing Medicago sativa within 30 d after grass sowing in Northwest Hebei.