Abstract: In order to know the potential ability and carrying capacity of Kobresia grassland during the withered grass period for Sanjiangyuan Region, nutritional value and carrying capacity are evaluated by approximate analysis method and in vitro gas production methods combined with grass production. Results indicate that edible grass production is 64.14 g穖^-2. The water, Ash, Ca, P, Ca/P, CF, ADF, NDF, EE and CP contents of air-dry grass samples are 7.16%, 5.66%, 1.13%, 0.04%, 38.47, 28.41%, 44.31%, 63.33%, 2.32% and 3.37%, respectively. The pH value and NH₃-N concentration of fermented grass in vitro are normal. IVDMD, DE and ME are 36.10%, 4.50 MJ穔g^-1 and 2.92 MJ穔g^-1, respectively. The yield of water, Ash, Ca, P, CF, ADF, NDF, EE and CP are 4.62, 3.59, 0.79, 0.02, 19.37, 28.46, 39.25, 1.42 and 2.35 g穖^-2, respectively. Quantity, DCP and ME carrying capacities are 1.06, 0.37 and 0.74 SU穐m^-2, respectively. This research validates that there is obvious spatial heterogeneity about the Kobresia grassland. Phosphorus and crude protein contents of the grassland are severely deficient. Therefore, nutrition is a key restricted factor for grazing livestock in this area.

Key words: Grass, Kobresia grassland, Nutritional value, Carrying capacity

摘要： 为探究三江源区枯草期嵩草(Kobresia)草地营养供给潜力和载畜量,采用概略养分分析法和体外产气法,结合产草量对枯草期牧草综合评定并确定其载畜量。结果表明:可食产草量为64.14 g·m^-2;以风干样为基础测定的水分、灰分(Ash)、钙(Ca)、磷(P)、钙磷比(Ca/P)、粗纤维(CF)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、粗脂肪(EE)和粗蛋白(CP)分别为7.16%,5.66%,1.13%,0.04%,38.47,28.41%,44.31%,63.33%,2.32%和3.37%;体外发酵pH和氨氮浓度均在正常范围内,体外干物质消化率(IVDMD)、消化能(DE)和代谢能(ME)为36.10%,4.50 MJ·kg^-1和2.92 MJ·kg^-1;水分,Ash,Ca,P,Ca/P,CF,ADF,NDF,EE和CP输出量分别为:4.62 g·m^-2,3.59 g·m^-2,0.79 g·m^-2,0.02 g·m^-2,42.51,19.37 g·m^-2,28.46 g·m^-2,39.25 g·m^-2,1.42 g·m^-2和2.35 g·m^-2;数量载畜量、可消化蛋白(DCP)载畜量和ME载畜量分别为1.06, 0.37和0.74 SU·hm^-2。研究证实嵩草草地空间异质性大,牧草中P和CP严重匮乏,营养成为限制家畜生产的关键因素。

关键词: 牧草, 嵩草草地, 营养价值, 载畜量