欢迎访问《草业学报》官方网站,今天是 分享到:

草业学报 ›› 2023, Vol. 32 ›› Issue (1): 154-164.DOI: 10.11686/cyxb2022165

• 研究论文 • 上一篇    

藏北高寒草甸土壤线虫群落结构和多样性对增氮的响应

沙玉宝1,2(), 干珠扎布1,2(), 胡国铮1,2, 王学霞3, 严俊4, 何世丞4, 高清竹1,2   

  1. 1.中国农业科学院农业环境与可持续发展研究所,北京 100081
    2.国家农业环境那曲观测实验站,西藏 那曲 852000
    3.北京市农林科学院植物营养与资源研究所,北京 100097
    4.那曲市草原站,西藏 那曲 852000
  • 收稿日期:2022-04-12 修回日期:2022-05-30 出版日期:2023-01-20 发布日期:2022-11-07
  • 通讯作者: 干珠扎布
  • 作者简介:E-mail: ganjurjav@foxmail.com
    沙玉宝(1997-),男,山东临沂人,在读硕士。E-mail: shayubao@caas.cn
  • 基金资助:
    国家自然科学基金(31901142);中央公益性科研院所基本科研业务费专项(BSRF202009);中国科协青年人才托举工程项目(2019QNRC001)

Response of soil nematode community structure and diversity to increased nitrogen in alpine meadows of northern Tibet

Yu-bao SHA1,2(), Ganjurjav HASBAGAN1,2(), Guo-zheng HU1,2, Xue-xia WANG3, Jun YAN4, Shi-cheng HE4, Qing-zhu GAO1,2   

  1. 1.Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China
    2.Nagqu National Experimental Station for Agri-environmental Observation,Nagqu 852000,China
    3.Institute of Plant Nutrition and Resources,Beijing Agricultural Forestry Academy,Beijing 100097,China
    4.Nagqu Grassland Station,Nagqu 852000,China
  • Received:2022-04-12 Revised:2022-05-30 Online:2023-01-20 Published:2022-11-07
  • Contact: Ganjurjav HASBAGAN

摘要:

土壤线虫在高寒草甸生态系统物质循环和能量传递过程中起重要作用。高寒草甸植物对氮沉降极为敏感,但增氮对土壤线虫群落结构和多样性的影响仍不明确。本研究在西藏那曲高寒草甸开展模拟氮沉降试验,设置0、7、20、40 kg N·hm-2·a-1 4个增氮水平(硝酸铵),研究增氮对高寒草甸土壤线虫群落结构和多样性的影响。结果表明:1)增氮显著改变了高寒草甸土壤线虫的群落组成,并且降低了线虫多样性和均匀度;2)N20、N40显著提高了食细菌线虫(Ba)类群的相对丰度,较对照组分别提高了30.4%和31.7%;3)线虫多样性指数(H′)和均匀度指数(J)均表现为Nck>N40>N20>N7,不同处理间植物寄生线虫指数(plant parasite index, PPI)、自由线虫成熟度指数(maturity index, MI)、瓦斯乐思卡指数(wasilewska index, WI)无显著差异。在不同增氮条件下,线虫通道指数(nematode channel ratio, NCR)均大于0.5,瓦斯乐思卡指数(WI)均大于1,说明研究区土壤线虫类群整体以食细菌线虫为主,矿化途径主要由食细菌真菌线虫参与;4)土壤中氨态氮含量和线虫总量及食细菌线虫数量显著正相关。本研究明确了施氮条件下食细菌线虫数量的增加是藏北高寒草甸土壤线虫总量增加的主要来源,为探究藏北高寒草甸生态系统对氮沉降的响应机制提供了参考。

关键词: 氮沉降, 生态指数, 线虫通道指数, 土壤动物, 植物生产力

Abstract:

Soil nematodes play an important role in material cycling and energy transfer processes in alpine meadow ecosystems. Alpine meadow plants are extremely sensitive to nitrogen deposition, but the effect of increased nitrogen on the structure and diversity of the soil nematode community remains unclear. In this study, we conducted a simulated nitrogen deposition experiment in alpine meadows in Nagqu, Tibet, with four levels of nitrogen enrichment: 0 (CK), 7, 20, and 40 kg N·ha-1·yr-1. Then, we investigated the effects of nitrogen enrichment on the structure and diversity of the soil nematode community. The results showed that: 1) Increased nitrogen significantly changed the soil nematode community composition in alpine meadows and reduced nematode diversity and evenness; 2) the N20 and N40 treatments significantly increased the relative abundance of bacterivore (Ba) taxa by 30.4% and 31.7%, respectively, compared with the control group; 3) The treatments could be ranked, from highest nematode diversity index and evenness index to lowest, as follows: Nck>N40>N20>N7. There were no significant differences in the plant parasite index, maturity index, and Wasilewska index (WI) among the treatments. The nematode channel ratio was greater than 0.5 and the WI was greater than 1 under different nitrogen enrichment conditions, indicating that the soil nematode taxa in the study area were mainly bacterivore nematodes, and that the main players in the mineralization pathway were bacterivore and fungivore nematodes; 4) The ammonia nitrogen content in soil was significantly and positively correlated with the total numbers of nematodes and bacterivores. This study clarified that the increase in the total number of soil nematodes in the alpine meadows of northern Tibet under nitrogen deposition is because of increased numbers of bacterivore nematodes. These results provide a reference for exploring how alpine meadow ecosystems in northern Tibet will respond to nitrogen deposition.

Key words: nitrogen deposition, ecological index, nematode channel ratio, soil fauna, plant productivity