Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe

作者：Xiaonan Wang, Chengyang Zhou, Shining Zuo, Yixin Ji, Wenxin Liu, Ding Huang · 发表于：PeerJ · 年份：2024 · DOI：10.7717/peerj.17031 · 被引用次数：12 · 研究领域：Soil Carbon and Nitrogen Dynamics、Mycorrhizal Fungi and Plant Interactions、Microbial Community Ecology and Physiology

Background In a context of long-term highly intensive grazing in grassland ecosystems, a better understanding of how quickly belowground biodiversity responds to grazing is required, especially for soil microbial diversity. Methods In this study, we conducted a grazing experiment which included the CK (no grazing with a fenced enclosure undisturbed by livestock), light and heavy grazing treatments in a desert steppe in Inner Mongolia, China. Microbial diversity and soil chemical properties ( i.e ., pH value, organic carbon, inorganic nitrogen (IN, ${\mathrm{NH}}_{4}^{+}$-N and ${\mathrm{NO}}_{3}^{-}$-N), total carbon, nitrogen, phosphorus, and available phosphorus content) both in rhizosphere and non-rhizosphere soils were analyzed to explore the responses of microbial diversity to grazing intensity and the underlying mechanisms. Results The results showed that heavy grazing only deceased bacterial diversity in the non-rhizosphere soil, but had no any significant effects on fungal diversity regardless of rhizosphere or non-rhizosphere soils. Bacterial diversity in the rhizosphere soil was higher than that of non-rhizosphere soil only in the heavy grazing treatment. Also, heavy grazing significantly increased soil pH value but deceased NH4+-N and available phosphorus in the non-rhizosphere soil. Spearman correlation analysis showed that soil pH value was significantly negatively correlated with the bacterial diversity in the non-rhizosphere soil. Combined, our results suggest ...