基于Meta分析的中国北方草地土壤pH对放牧的响应研究

Effects of grazing on soil pH of grassland in northern China based on meta-analysis

摘要:

基于Meta分析,通过对中国北方草地已开展的24个有关不同放牧强度对土壤pH影响的试验结果进行整合分析。结果表明:放牧轻度增加我国北方草地土壤pH值,平均效应值为0.009±0.006,增幅0.91%。放牧极显著增加温性草甸草原土壤pH值 (P＜0.01),但降低高寒草甸土壤pH值。不同放牧强度对pH平均效应值的影响无显著性差异,从高到低为轻度放牧＞重度放牧＞中度放牧。土壤全磷对放牧草地平均效应值具有显著负效应(P＜0.05),可以解释14.56%的效应值变异。土壤速效氮、速效磷、有机质、全钾和容重也是解释效应值变异的主要因素。放牧利用对北方草地土壤pH不会产生较大影响,中度放牧利用为最适宜的草地利用方式。

Abstract:

The grasslands in northern China are important ecological security barriers.Soil pH directly affects soil microbial activity and the form of carbon and nitrogen nutrient.Previous studies have paid little attention to the effects of grazing disturbance on soil pH and its driving factors.A meta-analysis based on the data from 24 experiments was undertaken to study the effects of different grazing intensities on soil pH.Our results showed that grazing disturbance slightly increased soil pH of grassland (by 0.91%),with an average effect size of 0.009±0.006.Grazing significantly increased soil pH of temperate meadow steppe (P＜0.01),but decreased effect size of alpine meadow.There was no significant difference in the average effect sizes among the different grazing intensities,following an order of light grazing ＞ heavy grazing ＞ moderate grazing.Soil total phosphorus had a significant and negative correlation with the average effect size of grassland soil pH (P＜0.05),which could explain 14.56% variation.Soil available nitrogen,available phosphorus,organic matter,total potassium and bulk density were all main factors to explain the variation of response value.Grazing did not have significant effects on soil pH,and moderate grazing was the most suitable.