植物生态学报 ›› 2025, Vol. 49 ›› Issue (12): 2043-2053.DOI: 10.17521/cjpe.2024.0453  cstr: 32100.14.cjpe.2024.0453

• 研究论文 • 上一篇    下一篇

不同水平氮添加对晋北赖草草地地上和地下净初级生产力的影响

卞嘉琛1, 王睿1,2,3, 高阳阳1,2,3, 梁雯君1,2,3, 晋红1, 张文轩1, 张晓荣1, 郝杰1,2,3, $\boxed{\hbox{王常慧}}$1,2,3, 董宽虎1,2,3,*(), 刁华杰1,2,3,*()   

  1. 1山西农业大学草业学院, 山西太谷 030801
    2草地生态保护与乡土草种质创新山西省重点实验室, 山西太谷 030801
    3山西右玉黄土高原草地生态系统国家定位观测研究站, 山西右玉 037200
  • 收稿日期:2024-12-12 接受日期:2025-03-04 出版日期:2025-12-20 发布日期:2026-01-19
  • 通讯作者: *董宽虎(dongkuanhu@126.com);
    刁华杰(huajie0933@163.com)
  • 基金资助:
    国家自然科学基金(U22A20576);国家自然科学基金(32301375);山西省基础研究项目(202203021212420)

Effect of different levels of nitrogen addition on aboveground and belowground net primary productivity in Leymus secalinus grassland in Northern Shanxi, China

BIAN Jia-Chen1, WANG Rui1,2,3, GAO Yang-Yang1,2,3, LIANG Wen-Jun1,2,3, JIN Hong1, ZHANG Wen-Xuan1, ZHANG Xiao-Rong1, HAO Jie1,2,3, $\boxed{\hbox{WANG Chang-Hui}}$1,2,3, DONG Kuan-Hu1,2,3,*(), DIAO Hua-Jie1,2,3,*()   

  1. 1College of Grassland Science, Shanxi Agricultural University, Taigu, Shanxi 030801, China
    2Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation, Taigu, Shanxi 030801, China
    3Youyu Loess Plateau Grassland Ecosystem National Research Station, Youyu, Shanxi 037200, China
  • Received:2024-12-12 Accepted:2025-03-04 Online:2025-12-20 Published:2026-01-19
  • Supported by:
    National Natural Science Foundation of China(U22A20576);National Natural Science Foundation of China(32301375);Basic Research Project of Shanxi Province(202203021212420)

摘要:

氮添加对草地生态系统地上生产力(ANPP)和地下生产力(BNPP)具有显著的影响。然而群落ANPP和BNPP对氮添加的不同响应以及其在不同水平氮添加下的饱和响应阈值目前尚不清晰。因此, 该研究以晋北赖草(Leymus secalinus)草地为研究对象, 设置8个不同氮添加水平(0、1、2、4、8、16、24、32 g·m-2·a-1), 于2017-2021连续5年监测植物ANPP、BNPP和总初级生产力(NPP)的变化, 并计算植物生产力的稳定性、氮饱和阈值以及氮响应效率。结果表明: (1) ANPP和NPP均随氮添加水平的提高呈非线性增加的模式。ANPP和NPP的氮饱和响应阈值(2017-2021年)分别为25.7 g·m-2·a-1和21.3 g·m-2·a-1。(2)植物ANPP和BNPP对氮添加具有不同的敏感性, 其中ANPP的敏感性高于BNPP。NPP的变化主要是由ANPP的变化引起的, 这表明随着氮添加水平的提高, 植物生产力向地上分配增加。(3) ANPP的氮响应效率(NREANPP)随氮添加水平的提高呈指数下降趋势, 而BNPP和NPP的氮响应效率(NREBNPP、NRENPP)随氮添加水平的提高呈线性下降趋势。(4)结构方程模型分析发现, 土壤NO-3-N含量和土壤pH间接调控着施氮年限和氮添加对ANPP和BNPP的影响; 并且低氮和高氮添加对植物ANPP和BNPP具有不同的调控机制, 在低氮处理下, ANPP和BNPP主要受氮添加的直接影响; 而在高氮处理下, 土壤无机氮含量和pH间接调控氮添加对ANPP和BNPP的影响。该研究呈现了晋北赖草草地生态系统植物生产力随氮添加水平呈非线性响应的特征, 为氮沉降背景下提高草地生态系统的服务功能提供了数据支撑。

关键词: 氮沉降, 地上净初级生产力, 地下净初级生产力, 氮响应效率, 响应阈值

Abstract:

Aims Nitrogen (N) addition can significantly affect the aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) of grassland ecosystems. However, the mechanisms underlying different responses of plant ANPP and BNPP to N addition and their saturation response thresholds at different levels of N addition are not clear.

Methods Eight N addition levels (0, 1, 2, 4, 8, 16, 24, 32 g·m-2·a-1) were set up in the Leymus secalinus grassland in Northern Shanxi, and the changes of plant ANPP, BNPP and total net primary productivity (NPP) were monitored for five years from 2017 to 2021. The temporal stability, N saturation threshold and N response efficiency of plant productivity were also calculated.

Important findings The results showed that: (1) ANPP and NPP were increased nonlinearly with the increase of N addition levels. The saturation response thresholds of ANPP and NPP across five years (2017-2021) were 25.7 g·m-2·a-1and 21.3 g·m-2·a-1, respectively. (2) ANPP and BNPP had different sensitivities to N addition, and the sensitivity of ANPP was higher than that of BNPP. The change in NPP was mainly caused by changes in ANPP, suggesting that plant productivity distribution to the aboveground increased as the level of N addition increased. (3) Nitrogen response efficiency of ANPP (NREANPP)showed an exponential downward trend with the increase of N addition levels, while the nitrogen response efficiency of BNPP (NREBNPP) and nitrogen response efficiency of NPP (NRENPP) showed a linear downward trend with the increase of N addition levels. (4) Structural equation model analysis showed that soil NO-3-N content and pH regulated the effects of N addition and duration on plant ANPP and BNPP. There were different regulatory mechanisms of ANPP and BNPP under low N and high N addition treatments. Both ANPP and BNPP were directly affected by N addition under low N addition treatments, while the soil inorganic N content indirectly regulated the response of ANPP and BNPP to N addition under high N addition treatments. This study indicates that plant productivity in grassland ecosystem responds nonlinearly with N addition levels, which provided dataset supporting for ecosystem service function of Leymus secalinus grassland in Northern Shanxi under the scenario of N deposition.

Key words: nitrogen deposition, aboveground net primary productivity, belowground net primary productivity, nitrogen response efficiency, response threshold