The sheep grazing experiment was carried out on the enclosed recovering natural grazing pastures of Dalinuorizhen of Keshiketeng Banner in Inner Mongolia in warm season to study the dynamic changes of forage nutrition contents. Different grazing systems (control, continuous grazing, 4 plots rotational grazing, 5 plots rotational grazing, and 6 plots rotational grazing) and two kinds of grazing intensities was made by using 2 × 5 complete random try design. The results showed that initial moisture, CP, EE and Ash contents in forage on no grazing area were higher than that on rotational grazing area and continuous grazing area, ADF and NDF contents were significant lower than that on grazing area; with the continuation of grazing seasons, the decline rate of forage nutritional value on no grazing area was the lowest, next the rotational grazing, last the continuous grazing; there were no significant differences in forage nutrition content among 4 plot rotation, 5 plot rotation and 6 plot rotation. Grazing system and grazing intensity had interactive effect on forage nutrition contents. Therefore, rotational grazing showed superiority that with continuation of forage growth seasons, forage nutrition value could be preserved better under proper grazing intensity.%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恢复中天然放牧草场,于2008年6～10月进行毛肉兼用细毛羊的暖季放牧试验.采用2×5完全随机试验设计,设定不同放牧方式(不放牧,连续放牧,四区、五区、六区轮牧)及2种放牧强度,研究围封过程中放牧绵羊对封育草场牧草营养物质含量的影响.结果表明,不放牧区牧草初水分、粗蛋白质、粗脂肪和粗灰分含量显著高于轮牧和连续放牧区,酸性洗涤纤维和中性洗涤纤维含量显著低于放牧区;随着放牧季节的延续,不放牧区牧草营养价值下降速度最慢,轮牧区次之,连续放牧处理下降最明显;四区、五区和六区轮牧处理间牧草营养物质含量变化差异不显著.放牧方式与放牧强度对草场营养物质含量动态变化表现出不同程度的瓦作效应.因此,在放牧强度适中时,划区轮牧能够体现其优越性,随着牧草生长季的延续,较好地保存牧草的营养价值.
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