在典型的草原中,土壤细菌社区结构和功能的牧场驱动的转变是由额外的N输入介导的
Lan Li1, Xiong Zhao He2, Mengyuan Wang1
1State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China.
The Science of the total environment
|December 23, 2023
概括
草食动物放牧和 (N) 添加的结合影响了土壤细菌的多样性. 添加和放牧的最佳水平可以增强土壤细菌多样性和生态系统功能,但高水平可能是有害的.
科学领域:
- 生态生态学 生态生态学
- 土壤科学 土壤科学
- 微生物学 微生物学
背景情况:
- 草食动物的放牧和 (N) 肥料是土壤微生物社区结构和功能的关键驱动因素.
- 放牧和N添加对土壤细菌的综合影响仍然在很大程度上未被探索,尽管它们有可能产生复杂的相互作用.
- 了解这些相互作用对于预测生态系统对全球变化的反应至关重要.
研究的目的:
- 研究长期草食动物放牧和添加对土壤细菌社区结构和功能的综合影响.
- 确定介导这些反应的关键无生物和生物因素.
- 确定最佳的管理策略,以保持土壤细菌健康和生态系统服务.
主要方法:
- 进行了一项为期17年的实地实验,使用不同的绵羊养率 (放牧) 和一个为期6年的实验,使用不同的N添加水平.
- 分析了土壤的非生物性质,植物群落组成和功能特征.
- 用分子技术和结构方程建模 (SEM) 来评估土壤细菌社区的结构和功能.
主要成果:
- 较高的养殖率 (8.7羊-1) 降低了土壤细菌的多样性. 在α-和β-多样性中,N添加分别显示了形和形反应,在10gNm−2年−1.1.2时出现了临界点.
- 适度放牧 (2.7绵羊ha-1) 和高N添加 (10g N m-2年-1) 的协同效应最大限度地提高了细菌α-多样性. 在高牧场 (8.7羊ha-1) 和N添加 (20gN m-2年-1) 的对比效应增加了β-多样性.
- 土壤的pH值,湿度,NO3−-N,C:营养比率,以及植物群体的特征 (例如,地表生物质,CWM_C) 显著影响了细菌群体. 通过这些因素,SEM揭示了放牧和N添加对细菌多样性和结构的间接影响.
- 放牧和N添加的相互作用增强了细菌网络的复杂性和稳定性,加速了土壤的碳 (C) 和N循环潜力.
结论:
- 适度的N应用 (<10gNm−2年−1) 与低养殖率 (<5.3羊ha−1) 相结合,可以支持土壤细菌的发展和关键的生态系统功能.
- 复杂的,非线性反应强调了需要综合管理策略,同时考虑放牧和N投入.
- 为了了解全球变化驱动因素对土壤微生物群落和生物地球化学循环的长期影响,进一步的研究是必不可少的.
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