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中国沙漠 ›› 2024, Vol. 44 ›› Issue (6): 178-186.DOI: 10.7522/j.issn.1000-694X.2024.00071

• • 上一篇    下一篇

内蒙古荒漠草原土壤氨挥发对外源氮输入的响应

饶玉良1(), 曹春1, 张晓雪2, 鲁畅3, 岳平2()   

  1. 1.西北师范大学 地理与环境科学学院 甘肃省绿洲资源环境与可持续发展重点实验室,甘肃 兰州 730070
    2.中国科学院西北生态环境资源研究院 乌拉特荒漠草原研究站/甘肃省寒区旱区逆境生理与生态重点实验室,甘肃 兰州 730000
    3.河套学院 化学与环境工程系,内蒙古 巴彦淖尔 015000
  • 收稿日期:2024-05-13 修回日期:2024-08-28 出版日期:2024-11-20 发布日期:2024-12-06
  • 通讯作者: 岳平
  • 作者简介:岳平(E-mail: yueping375@163.com
    饶玉良(1999—),男,福建三明人,硕士研究生,主要从事土壤氮循环相关研究。E-mail: 18859879660@163.com
  • 基金资助:
    中国科学院青年创新促进会会员专项经费项目(2022437);内蒙古阴山北麓草原生态水文国家野外科学观测研究站开放基金重点项目(YSS202102)

Response of soil ammonia volatilization to exogenous nitrogen input in Inner Mongolian desert grasslands

Yuliang Rao1(), Chun Cao1, Xiaoxue Zhang2, Chang Lu3, Ping Yue2()   

  1. 1.Key Laboratory of Oasis Resource Environment and Sustainable Development of Gansu Province,School of Geography and Environmental Science,Northwest Normal University,Lanzhou 730070,China
    2.Ulat Desert Grassland Research Station / Key Laboratory of Adverse Physiology and Ecology in Cold and Arid Regions of Gansu Province,Northwest Institute of Eco-Environment Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    3.Department of Chemical and Environmental Engineering,Hetao College,Bayannur 015000,Inner Mongolia,China
  • Received:2024-05-13 Revised:2024-08-28 Online:2024-11-20 Published:2024-12-06
  • Contact: Ping Yue

摘要:

氨(NH3)挥发是干旱区土壤氮素损失的重要途径。内蒙古荒漠草原对气候变化十分敏感,关于土壤氨挥发如何响应氮沉降的认识仍十分有限。本研究以内蒙古荒漠草原为对象,采用通气法原位动态观测手段,研究在不同氮沉降背景下土壤氨挥发特征及其关键驱动因子,为荒漠草原区退化植被恢复和土壤氮素管理提供关键的科学支撑。结果表明:土壤氨挥发速率随着氮素输入量的增加呈现显著增加的趋势,但在氮输入后前20天氨挥发呈现指数下降的趋势,之后趋于平缓。氮输入后前20天氮素在低氮输入(0.5~3 g·m-2·a-1)下以NH3形式损失量最少,仅为33%~39%,而在中高氮输入水平(6~48 g·m-2·a-1)损失量较高,为55%~75%。土壤氨挥发速率与土壤铵态氮含量、硝态氮含量和土壤湿度显著正相关(P0.001),而与土壤pH值显著负相关(P0.01)。氮输入量和土壤湿度是影响土壤氨挥发最重要的因素,且氮输入后主要通过改变土壤铵态氮含量和pH值,进而间接调控土壤氨挥发过程。内蒙古荒漠草原土壤氨挥发对氮输入的响应十分敏感,且低量的氮输入比高量的氮输入更有利于土壤氮素的保持,这为进一步深入研究氮沉降升高背景下荒漠草原氮循环过程提供了科学支撑。

关键词: 荒漠草原, 氨挥发, 氮沉降, 损失率, 结构方程模型

Abstract:

Ammonia (NH3) volatilization is one of the important pathways of soil nitrogen loss in arid zones. However, the understanding of how soil ammonia volatilization responds to nitrogen deposition in the desert grasslands of Inner Mongolia, which is very sensitive and vulnerable to climate change, is still very limited. Therefore, this study takes Inner Mongolia desert grassland as the research object, and adopts the in situ dynamic observation means of the ventilation method to study the characteristics of soil ammonia volatilization and its key driving factors under different nitrogen deposition backgrounds, so as to provide key scientific support for the restoration of degraded vegetation and soil nitrogen management in the desert grassland area. The results of this study showed that soil ammonia volatilization rate showed a significant increase with increasing nitrogen input, but ammonia volatilization showed an exponential decrease in the first 20 days after nitrogen input, and then leveled off. It was also found that nitrogen loss in the form of NH3 in the first 20 days after nitrogen input was lowest at low nitrogen inputs (0.5-3 g·m-2·a-1) at 33-39 percent, and higher at medium to high nitrogen input levels (6-48 g·m-2·a-1) at 55-75 percent. Further analysis showed that soil ammonia volatilization rate was significantly and positively correlated with soil ammonium nitrogen content, nitrate nitrogen content and soil moisture (P0.001), while it was significantly and negatively correlated with soil pH (P0.01). The results of structural equation modeling showed that N input and soil moisture were the most important factors affecting soil ammonia volatilization, and that N input mainly regulated the soil ammonia volatilization process by changing soil ammonium nitrogen content and pH, which in turn indirectly regulated the process of soil ammonia volatilization. In conclusion, the response of soil ammonia volatilization in Inner Mongolia desert grassland to nitrogen input is very sensitive, and the low amount of nitrogen input is more favorable to soil nitrogen retention than the high amount of nitrogen input, which provides scientific support for further in-depth study of nitrogen cycling in desert grassland under the background of elevated nitrogen deposition.

Key words: desert grassland, ammonia volatilization, nitrogen deposition, loss rate, structural equation modeling

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