【摘要】 在收获期将高丹草（Sorghum bicolor×Sorghum sudanese）、玉米（Zea mays）和象草（Pennisetum purpureum）3种C₄禾本科牧草不同节位的茎秆、叶片和叶鞘分离,分别测定其粗蛋白（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、非结构性碳水化合物（NSC）含量以及干物质体外消化率（IVDMD）等饲用品质性状。结果表明:玉米IVDMD和CP含量最高,显著高于高丹草和象草（P<0.05）;玉米和高丹草的NSC含量显著高于象草（P<0.05）;象草NDF和ADF含量最高,玉米的最低。玉米叶片CP含量高于茎秆和叶鞘,但象草和高丹草茎秆CP含量显著高于叶片和叶鞘（P<0.05）;象草CP含量随着节位的降低逐渐升高,高丹草则相反。3种C₄牧草不同节位叶鞘和叶片中可溶性碳水化合物（WSC）含量极显著低于茎秆（P<0.01）,其中高丹草茎秆WSC含量显著高于玉米（P<0.05）,象草的最低;高丹草倒3～4节茎秆中的WSC含量最高,倒9～10节显著降低;玉米倒3节后茎秆中的WSC含量逐节升高,倒8～10节最高;象草茎秆WSC含量呈现V字形变化,倒1～4节逐节下降,随后逐节升高,倒11节最高。因此收获玉米应降低留茬高度,而高丹草和象草适宜刈割高度分别为倒8节和倒11节。更多还原

【Abstract】 At harvest stage, the contents of nonstructural carbohydrates（NSC）, crude protein（CP）, neutral detergent fiber（NDF）, acid detergent fiber（ADF）, and in vitro dry matter digestibility（IVDMD） of stem, leaf and sheath were measured in different internodes of maize（Zea mays）, elephant grass（Pennisetum purpureum） and sorghum-sudan hybrid（Sorghum bicolor×Sorghum Sudanese）. The results showed that the IVDMD and CP content of maize was higher than those of sorghum-sudan hybrid grass and elephant grass（P<0.05）; the content of NSC in maize and sorghum-sudan hybrid grass was higher than that of elephant grass（P<0.05）; the content of NDF and ADF was the highest in elephant grass, and lowest in maize. The CP content in maize leaf was higher than that in stem and sheath（P<0.05）, but the CP content in the stem of elephant grass and sorghum-sudan hybrid grass was much higher than that in leaf and sheath（P<0.05）; the CP content in elephant grass increased with the decrease of node position, while the content of CP in sorghum-sudan hybrid grass decreased with the reduction of node position. The content of water soluble carbohydrates（WSC） in the stem of three forage grasses was significantly higher than that in sheath and leaf（P<0.01）, and the WSC content in sorghum-sudan hybrid grass stem was significantly higher than that of maize stem（P<0.05）, in which the WSC content in elephant grass was the lowest; the content of WSC in the top 3^rd～4^th node of sorghum-sudan hybrid grass was the highest; the content of WSC in maize stem increased after top 3^rd node with the decrease of node positions; the WSC content in elephant grass stem showed "V" pattern, which decreased from the top 1^st～4^th nodes, and then increased from the top 8^th～10^th nodes, in which the top 11^th node had the highest value.In conclusion, the cutting height in maize can be reduced as much as possible, while for the suitable cutting height in sorghum-sudan hybrid grass and elephant grass is about from the top 8^th and 11^th node, respectively.更多还原