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生态学杂志 ›› 2025, Vol. 44 ›› Issue (7): 2248-2258.doi: 10.13292/j.1000-4890.202507.010

• 研究报告 • 上一篇    下一篇

短期氮沉降对呼伦贝尔辉河流域围封和刈割草地土壤呼吸组分的影响

靳三玲,曲艳,韩子晨,王德平,戎郁萍*   

  1. (中国农业大学草业科学与技术学院, 北京 100193)
  • 出版日期:2025-07-10 发布日期:2025-07-11

Effects of short-term nitrogen addition on soil respiration components in enclosed and mown grasslands in the Hui River Basin of Hulunbuir.

JIN Sanling, QU Yan, HAN Zichen, WANG Deping, RONG Yuping*   

  1. (College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China).
  • Online:2025-07-10 Published:2025-07-11

摘要: 土壤呼吸是陆地生态系统碳循环的关键过程,由自养呼吸和异养呼吸两部分组成,受土地利用方式和环境变化的影响。在大气氮沉降背景下,草地利用方式对土壤呼吸的作用过程尚不明确。本研究以呼伦贝尔辉河流域长期围封与刈割利用的草地为研究区,设置了0(N0)、2(N2)、5(N5)和10 g·m-2·a-1(N10)4个氮添加水平,研究了氮添加对不同利用方式草地生长季土壤总呼吸(Rs)、自养呼吸(Ra)和异养呼吸(Rh)速率的影响及其机制。结果表明:氮添加与草地利用方式未改变土壤呼吸速率的时间动态,最大值均出现在7—8月;氮添加与草地利用方式显著影响了RsRaRhP<0.05),对Ra/Rh无显著影响(P>0.05),二者交互作用对土壤呼吸速率无显著影响(P>0.05);相较于N0,N2处理对RsRa无显著影响(P>0.05),N5处理显著提高了围封草地和刈割草地的Rs(13.8%、13.1%)与Ra(29.8%、28.3%)(P<0.05),N10处理显著提高了刈割草地的Rs(7.0%),氮添加对围封和刈割草地Rh均无显著影响(P>0.05);刈割显著提高了土壤呼吸速率(P<0.05),刈割草地Rs在N0、N5、N10处理下显著高于围封草地,Ra在N0处理下显著高于围封草地(P<0.05);土壤湿度是氮添加下土壤呼吸及其组分的主要调控因子,草地利用方式主要通过土壤温度和地下生物量调控土壤呼吸及其组分;刈割增加了RhRa的水分敏感性和温度敏感性,围封草地氮添加提高了Ra的水分敏感性和温度敏感性,同时增加了Rh的水分敏感性,但降低了其温度敏感性;刈割草地氮添加增加了Ra的水分敏感性,降低了其温度敏感性。本研究揭示了草甸草原土壤呼吸及其组分对氮添加与草地利用方式的响应特征及机制,可为草地生态系统的科学管理提供理论依据。


关键词: 氮添加, 围封草地, 刈割草地, 土壤呼吸, 自养呼吸, 异养呼吸

Abstract: Soil respiration, a pivotal process of the carbon cycle in terrestrial ecosystems, comprises autotrophic respiration (Ra) and heterotrophic respiration (Rh), and is influenced by land use patterns and environmental changes. However, the response of soil respiration to grassland utilization patterns under the background of nitrogen (N) deposition remains unclear. In this study, we examined the effects of N addition on the rates of soil respiration (Rs) and its components (Ra and Rh) in long-term enclosed and mown grasslands during the growing season in the Hui River Basin of Hulunbuir. There were four levels of N addition, including 0 (N0), 2 (N2), 5 (N5), and 10 g·m-2·a-1 (N10). The results showed that N addition and grassland utilization patterns did not alter the temporal dynamics of soil respiration rate, with peak values observed in July-August. Nitrogen addition and grassland utilization patterns significantly affected Rs, Ra, and Rh (P<0.05), while had no effects on the ratio of Ra/Rh (P>0.05). Furthermore, there was no interactive effect of N addition and grassland utilization patterns in affecting soil respiration rate (P>0.05). The N2 treatment did not affect Rs or Ra (P>0.05). However, the N5 treatment significantly increased Rs (by 13.8% and 13.1%) and Ra (by 29.8% and 28.3%) in both enclosed and mown grasslands, respectively (P<0.05). The N10 treatment significantly increased Rs (by 7.0%) in mown grassland (P<0.05). Additionally, N addition did not affect Rh in either enclosed or mown grasslands (P>0.05). Mowing significantly increased soil respiration rates (P<0.05). Rs in mown grassland was significantly higher than in enclosed grassland under the N0, N5, and N10 treatments, while Ra was significantly higher in mown grassland only under the N0 treatment (P<0.05). Soil moisture was the main regulator of soil respiration and its components under N addition, whereas grassland utilization patterns regulated soil respiration and its components primarily through altering soil temperature and belowground biomass. Compared to fencing, mowing increased the moisture and temperature sensitivity of Rh and Ra. Moreover, N addition in enclosed grasslands enhanced the moisture and temperature sensitivity of Ra and the moisture sensitivity of Rh, but decreased the temperature sensitivity of Rh. In mown grasslands, N addition increased the moisture sensitivity of Ra but decreased its temperature sensitivity. Our results enhance the mechanistic understanding of the responses of soil respiration and its components to N addition and grassland utilization patterns in meadow steppe, which can provide a theoretical basis for the scientific management of grassland ecosystems.


Key words: nitrogen addition, enclosed grassland, mown grassland, soil respiration, autotrophic respiration, heterotrophic respiration