State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China.
College of Earth Science, Chengdu University of Technology, Chengdu, China.
PLoS One. 2019 Apr 22;14(4):e0215223. doi: 10.1371/journal.pone.0215223. eCollection 2019.
Grazing has important influences on the structures and functions of grassland ecosystems, but the effects of grazing patterns on grassland biomass and soil environments in China remain unclear.
We employed a meta-analysis to identify the response of biomass and soil environments to different grazing patterns in China.
Peer-reviewed journal articles were searched using the Web of Science and China National Knowledge to compile a database. A total of 1011 sets of sample observations satisfied the sampling standards; these were derived from 140 study sites and were obtained from 86 published articles. We conducted random effects meta-analyses and calculated correlation coefficients with corresponding 95% confidence intervals.
Grazing significantly decreased the total biomass, aboveground biomass (AGB), belowground biomass (BGB), soil organic matter, soil total nitrogen, soil total phosphorus and soil water content but increased the root-to-shoot ratio, soil available nitrogen, soil pH and bulk density. Generally, increasing grazing intensity and duration significantly increased the effects of grazing on the biomass and soil environment. Additionally, the smallest effects of grazing on the biomass and soil environments were observed under light grazing and cattle grazing alone. Moreover, non-growing season grazing significantly increased AGB, while annual grazing and growing-season grazing significantly reduced AGB. Furthermore, AGB was positively correlated with soil organic matter, soil available phosphorus and bulk density, while BGB was negatively correlated with pH.
These findings highlight the importance of grazing patterns in the biomass and soil environment response to grazing and suggest that cattle grazing alone and grazing during the non-growing season are beneficial for improving the quality of grassland in China.
放牧对草原生态系统的结构和功能有重要影响，但放牧方式对中国草原生物量和土壤环境的影响仍不清楚。
我们采用荟萃分析来确定生物量和土壤环境对中国不同放牧方式的响应。
使用 Web of Science 和中国国家知识基础设施检索同行评审期刊文章，以编制数据库。共有 1011 组符合抽样标准的样本观测值；这些样本来自 140 个研究点，取自 86 篇已发表的文章。我们进行了随机效应荟萃分析，并计算了具有相应 95%置信区间的相关系数。
放牧显著降低了总生物量、地上生物量（AGB）、地下生物量（BGB）、土壤有机质、土壤全氮、土壤全磷和土壤含水量，但增加了根冠比、土壤有效氮、土壤 pH 值和土壤容重。一般来说，增加放牧强度和时间会显著增加放牧对生物量和土壤环境的影响。此外，在轻度放牧和单独放牧牛的情况下，放牧对生物量和土壤环境的影响最小。此外，非生长季节放牧显著增加了 AGB，而全年放牧和生长季节放牧则显著降低了 AGB。此外，AGB 与土壤有机质、土壤有效磷和土壤容重呈正相关，而 BGB 与 pH 值呈负相关。
这些发现强调了放牧方式对生物量和土壤环境对放牧响应的重要性，并表明单独放牧牛和非生长季节放牧有利于提高中国草原的质量。
