育龄及刈割频次对栽培甘草营养成分及消化率的影响

Effects of growth years and cutting times on nutrient composition and digestibility of cultivated Glycyrrhiza uralensis

为明确刈割次数对乌拉尔甘草(Glycyrrhiza uralensis)草产量、营养品质及消化率的影响,测定并分析了种植第2和第3年的乌拉尔甘草不同刈割处理下生长发育特性、草产量、营养品质及消化率。结果表明,随着生长年限的增加,不同育龄甘草株高、茎粗、茎叶比、鲜干草产量和鲜干比呈上升趋势,总分枝数呈下降趋势;干物质中粗蛋白、粗脂肪和粗灰分含量呈下降趋势;中性洗涤纤维、酸性洗涤纤维、酸性洗涤木质素含量呈上升趋势;48 h干物质消化率呈下降趋势。多次刈割的甘草株高累积量、茎粗累积量和分枝数累积量及总草产量明显高于刈割1次处理,刈割2次和3次处理的干草粗蛋白和粗灰分含量显著高于刈割1次处理(P<0.05);且随刈割次数的增加,干草的中性洗涤纤维、酸性洗涤纤维、木质素及总单宁含量呈显著下降趋势(P<0.05),其香豆素、甘草酸、甘草苷含量及48 h干物质消化率呈显著上升趋势(P<0.05)。研究结果表明,在库尔勒地区刈割多次能提高甘草草产量和营养品质,是适宜当地甘草的管理措施。

To determine the effects of cutting time on the yield,nutritional quality,and digestibility of Glycyrrhiza uralensis,its growth and development characteristics,grass yield,nutritional quality,and digestibility were measured and analyzed under different cutting treatments in the second and third years of planting.The results showed that with increasing growth years,the plant height,stem diameter,stem-to-leaf ratio,fresh hay yield,and fresh-to-dry ratio of licorice of different reproductive ages showed an upward trend,and the total number of branches showed a downward trend.The contents of crude protein,crude fat,and crude ash in dry matter showed a downward trend;contents of neutral detergent fiber,acid detergent fiber,and acid detergent lignin increased;whereas the 48 h dry matter digestibility decreased.Plant high accumulation,stem diameter accumulation,branch number accumulation,and total grass yield of multiple cuttings were significantly higher than those of the single cutting.The crude protein and crude ash contents of hay after two and three cuttings were significantly higher than those of the single cutting(P<0.05).As the cutting time increased,the contents of neutral detergent fiber,acid detergent fiber,lignin,and total tannin in hay decreased significantly,whereas the contents of coumarin,glycyrrhizic acid,glycyrrhizin,and 48 h dry matter digestibility of hay increased significantly.In summary,multiple cuttings in the Korla area can improve the yield and nutritional quality of licorice grass compared with a single cutting.Multiple cuttings are a suitable management measure for this area.