中文摘要：

在测定贵州石阡县五老山天然生长的21种牧草的生物学性状及养分含量的基础上，利用营养类型划分及系统聚类方法，对植株的生物学性状及营养价值进行综合评价，以期明晰21种天然牧草的生物学性状及营养含量特性，为石阡天然牧草资源的开发利用提供理论依据。结果表明，21种牧草中，单株净产量较高的牧草有金荞麦、律草等11种，占样本总量的52％：抗逆性较好的牧草有知风草、画眉草等lO种，占样本量的49％；营养含量较优的有金荞麦、狼尾草等13种牧草，占样本量的62％，因此，贵州石阡天然牧草有较大的开发、利用价值。以此为基础，将21种牧草划分为N、N—C、C—N、C4种营养类型，其中N、N—C型牧草较适合对哺乳期、产蛋期等阶段的畜禽进行饲喂，而C—N、C型较适合对育肥期等阶段的畜禽进行饲喂。最后，对13个参试指标进行聚类分析，按农艺特性聚类可分为6类，其中，第Ⅲ、Ⅳ、V、Ⅵ类牧草单株净产量较高，可作为高产牧草选育素材或推广种植，但各有特点；按生化特性聚类可分为3类，其中，第Ⅱ类牧草可作为高蛋白、抗逆牧草品种的选育素材，第Ⅲ类牧草可作为抗逆牧草品种的选育素材加以利用；按营养特性聚类可分为5类，其中，第Ⅲ、Ⅳ类牧草可作为高蛋白低脂或低纤维的优质牧草进行选育及利用。

英文摘要：

Based on determinating biological traits and ingredients of 21 forages at Wulao mountain in Shiqian county, Guizhou province, using trophic types and system clustering method, biological traits and nutritional value of plants were compared. This study expected to provide references for development and utilization of forage resources. The results showed that 11 kinds of forage （Fagopyrum dibotrys Hara, Humulu~ scandens ect.） had higher plant net yield, accounting for 52% of total sample, 10 kinds of forage （Eragrostis ferruginea Beauv., E. pilosa Beauv. ect.） had better resistance, accounting for 49%, 13 kinds of forage （F. dibotrys Hara, Pennisetum alopecuroides Spreng. ect.） had outstanding nutritional content, accounting for 62%. Therefore, the natural forages in Shiqian county had large development and utilization value. 21 kinds of forage were divided into N, N-C, C-N, C trophic types, N and N-C forages were suitable for feeding livestock and poultry in lactation and laying period, C-N and C forages were more suitable for feeding livestock in fattening period. Finally, 13 tested indices were analyzed by cluster analysis. According to agronomic traits, these forages could be divided into 6 categories, and III, IV, V, VI had higher plant net, could be planted or bred as pasture with different characteristics. According to biochemical characteristics, these forages could be divided into 3 categories, and II could be used as breeding material of high protein and resistance, and grass III could be used as breeding material resistant. According to nutritional characteristics, these forages could be divided into 5 categories, III, IV could be bred as high protein, low fat or low fiber quality forage.