Abstract: To investigate the effects of three grazing factors:grazing intensity,livestock type and grazing system,and four environmental factors:sampling time,grassland type,average annual temperature and average annual precipitation,on the nutritional quality of natural grassland communities in northern China,this study conducted a Meta-analysis based on random effects and Bayesian methods on data collected from 35 Chinese and English literature to quantitatively analyze the effects of above seven factors (Crude protein,ether extract,crude fiber,acid detergent fiber,neutral detergent fiber,ash and nitrogen free extract) by combining random forest method. The results indicated that grazing could increase the crude protein content and decrease the fiber content of the grassland community,which overall leads to an improvement in the nutritional quality of the remaining portion of the grassland community. Additionally,all seven factors had significant effects on grazing,but different factors had different impacts on the various nutritional quality indicators. This study provided some data and references for the management and further researches on the natural grasslands based on forage quality in northern China.

Key words: Grazing, Natural grassland, Nutrient quality, Meta-analysis

摘要： 为探究放牧强度、家畜类型和放牧制度3种放牧因素以及采样时间、草地类型、年均温和年均降水量4种环境因素对中国北方天然草地群落营养品质的影响,本研究通过对35篇中英文文献,共计306组数据进行了基于随机效应和贝叶斯方法的Meta分析,定量研究了放牧对草地群落营养品质(粗蛋白、粗脂肪、粗灰分、无氮浸出物、粗纤维、酸性和中性洗涤纤维含量)的效应,并结合随机森林方法,研究了7种因素对放牧效应的影响。结果表明,放牧可以增加草地群落粗蛋白含量,减少群落纤维含量,提高草地群落存留部分的营养品质,同时7种因素均对放牧效应存在显著影响,但对于不同营养品质指标,不同因素对放牧效应的影响存在差异。本研究为我国北方天然草地基于牧草品质的管理和研究工作提供了资料和参考。

关键词: 放牧, 天然草地, 营养品质, Meta分析