恢复阶段退化草地资源与营养评价

The evaluation of grassland resources and its nutrition in the recovering degraded grassland

选取内蒙古自治区克什克腾旗达来诺日镇典型草原区封育7年恢复中天然放牧草地,于2008年6-10月对草地进行野外实地考察和调查,分析草地生产力、草地资源以及草地营养物质动态变化并对草地牧草饲用价值进行评价,进而探讨草地理论载畜能力,为建立科学合理的围封恢复草地(原)放牧管理体系以及促进草地畜牧业的可持续发展提供理论指导。结果表明,经过7年的围封恢复,退化至冷蒿(Artemisia frigida)+小禾草阶段的草原生态系统基本恢复到以羊草(Leymus chinensis)和克氏针茅(Stipa krylovii)为主的草原群落,整个生长期群落平均盖度37.5%,密度184.6株/m2,平均自然高度18.3 cm,平均鲜草生物量154.3 g/m2,最高产量达到358.6g/m2;在整个牧草生长期,草群保持着较高的粗蛋白(CP)、粗脂肪(EE)、可消化总养分(TDN)和代谢能(ME)含量,平均分别为12.06%、1.87%、57.4%和8.31 MJ/kg,体现出封育后草地牧草较高的饲用价值;根据草地牧草产量估算得出的暖季产量载畜量为0.656 hm2/羊单位,根据牧草与绵羊营养指标(CP、ME、TDN)供需关系估算出草地营养载畜量分别为0.513、0.802和0.774 hm2/羊单位。试验区草地经过7年围封,生态恢复效果明显,草地承载力提高,优等饲用牧草种类增多,营养价值高,家畜亦喜食,适于牛羊适度放牧利用。

From June to October 2008, the field investigation and surveys on the encloseed （tor seven yeas） recovery grassland of natural grazing pastures were conducted to analyze production capacity, pasture resources and dynamic changes of vegetation community nutrition at Dalinuori Town, Keshiketeng Banner, the Inner Mongolia Autonomous Region. Furthermore, the feeding value and optimum carrying capacity of the pasture were also evaluated to provide a theoretical guidance for establishing scientifically a grazing management system of enclosed recovery pastures and promoting the sustainable development of grassland animal husbandry. The results showed that the grassland ecosystem had been recovered to Leymus chinensis and Stipa krylovii steppe communitybased from Artemisia frigida steppe after 7 years of enclosed restoration. The community characteristics of vegetation were improved; average coverage was 37.5%, density was 184.6 plants/m^2 , average height was 18.3 cm, fresh biomass was 154.3 g/mz and the highest yield was 358.6 g/m^2 in the whole growth period. The forage maintained high levels of CP, EE, TDN and ME; averaging 12.06%, 1.87%, 57.4% and 8.31 MJ/kg respectively. Based on forage yield in the warm season yield carrying capacity was calculated to 0. 656 hm2/sheep-unit. However, according to forage and sheep nutrition indicators （CP, EE and TDN） supply-demand relation＇the nutrients carrying capacity were estimated to 0. 513, 0. 802 and 0. 774 hm2/sheep-unit respectively. Therefore, the degraded grassland was resumed after 7 years of enclosed restoration＇ with higher grassland carrying capacity, excellent feed resources and better forage nutrition value compared with the control. The enclosure recovery grassland can be moderately grazed for sheep and cattle.