长期放牧下不同家畜对高寒灌丛饲草生物量和品质的影响

The effect of long-term grazing of different livestockson the biomass and quality of forage grassin alpine shrubland

摘要:

于2020年7-8月在东祁连山天祝高寒地区测定了放牧甘肃马鹿(Cervus elaphus kansuensis)、混牧牦牛(Bos grunniens)和藏羊(Ovis aries)34年的灌丛草地的饲草生物量和营养品质,以期为高寒灌丛草地放牧管理提供科学依据。结果表明:马鹿样地的饲用草本总生物量为1 423.78 kg/hm2,灌木总生物量为107 789.72 kg/hm2,而混牧牦牛和藏羊样地的饲用草本总生物量为342.63 kg/hm2,灌木的总生物量为176 279.54 kg/hm2;放牧马鹿样地中饲用草本的可溶性糖、酸性洗涤纤维和中性洗涤纤维分别为8.12%、36.70%和52.71%,均显著高于混牧牦牛和藏羊样地(P＜0.05),分别高46.31%、6.53%和10.98%;杯腺柳(Salix cupularis)叶片的中性洗涤纤维含量、小叶金露梅(Potentilla fruticose)叶片的酸性洗涤纤维含量、小叶金露梅枝条和高山绣线菊(Spiraea alpine)叶片的相对饲喂价值分别为58.96%、51.31%、41.48%和76.94%,均显著高于混牧牦牛和藏羊样地(P＜0.05),但高山绣线菊枝条的粗蛋白、高山绣线菊叶片的中性洗涤纤维、小叶金露梅枝条的酸性洗涤纤维和中性洗涤纤维以及杯腺柳叶片、小叶金露梅叶片和饲用草本的相对饲喂价值相反;放牧马鹿样地饲用草本的30小时中性洗涤纤维消化率、体外30、48 h干物质的消化率均显著低于牦牛和藏羊样地(P＜0.05),分别低12.22%、12.42%和5.20%,其余指标均无显著性差异。综上所述,长期放牧马鹿有利于提高草地生产性能。

Abstract:

In order to provide a scientific basis for grazing management of alpine shrub grassland,the biomass and nutrient quality of shrub grassland grazed by Gansu wapiti(Cervus elaphus kansuensis) and the mixedly grazed by yak (Bos grunniens) and Tibetan sheep (Ovis aries) were studied from July to August in 2020 in the Tianzhu alpine region of east Qilian Mountains where grazing has lasted for 34 years.The results showed that the total biomass of herbs and shrubs were 1 423.78 kg/hm2 and 107 789.72 kg/hm2 in Gansuwapiti plot respectively,whereas the total biomass of herbs and shrubs were 342.63 kg/hm2 and 176 279.54 kg/hm2 in yak-Tibetan sheep plot respectively.The soluble sugar,acid detergent fiber and neutral detergent fiber of forage herbs in the grazing wapiti plots were 8.12%,36.70% and 52.71%,respectively,which were significantly higher than those in the mixed grazing yak and Tibetan sheep plots (P＜0.05),and were 46.31%,6.53% and 10.98% higher,respectively.The neutral detergent fiber of leaves of Salix cupularis,the acidic detergent fiber of leaves of Potentilla fruticose,the relative feeding value of branches of Potentilla fruticose and leaves of Spiraea alpine were 58.96%,51.31%,41.48% and 76.94%respectively,which were significantly higher than those in yak-Tibetan sheep plot (P＜0.05).But the crude protein of branches and the neutral detergent fiber of leaves of Spiraea alpine,the acid detergent fiber and neutral detergent fiber of branches of Potentilla fruticose and the relative feeding value of leaves of Salix cupularis,Potentilla fruticose and herbs showed the opposite trend.The 30 hour neutral detergent fiber digestibility,the 30 hour and 48 hour dry matter digestibility in vitro of herbs were significantly lower than those in yak-Tibetan sheep plot (P＜0.05),which were 12.22%,12.42% and 5.20% lower,respectively.There was no significant difference in other indexes.In conclusion,long-term grazing of Gansu wapiti is beneficial to improve the productivity of grassland.