Chin J Plant Ecol ›› 2024, Vol. 48 ›› Issue (3): 317-330.DOI: 10.17521/cjpe.2023.0086

• Research Articles • Previous Articles     Next Articles

Effects of long-term grazing and nitrogen addition on the growth of Stipa bungeana population in typical steppe of Loess Plateau

HUANG Ling1, WANG Zhen1, MA Ze2, YANG Fa-Lin2, LI Lan1, SEREKPAYEV Nurlan3, NOGAYEV Adilbek3, HOU Fu-Jiang1,*()   

  1. 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
    2Grassland Workstation of Ningxia Huizu Autonomous Region, Yinchuan 750002, China
    3Department of Agriculture and Plant Growing, Saken Seifullin Kazakh Agrotechnical University, Astana 010011, Kazakhstan
  • Received:2023-03-29 Accepted:2023-09-12 Online:2024-03-20 Published:2024-04-24
  • Contact: *(
  • Supported by:
    National Program for S&T Collaboration of Developing Countries(KY202002011);Innovative Research Team Program of the Ministry of Education(IRT-17R50)


Aims Populations are the basis for the formation and development of the structure and function of grassland ecosystems. However, long-term grazing and global climate change like nitrogen addition profoundly impact the growth and reproduction of populations, such as Stipa bungeana, a dominant species in typical steppe of the Loess Plateau that has a high ecological and economic value. This study investigated how grazing and nitrogen addition affect the growth of S. bungeana.

Methods The study was based on a long-term rotational sheep grazing experiment in the typical steppe of the Loess Plateau. A completely randomized split-plot experimental design was employed, with stocking rate (0, 2.7, 5.3, 8.7 sheep·hm-2) as the main factor and nitrogen addition levels (0, 5, 10, 20 g·m-2) as the secondary factor. Morphological traits, aboveground biomass, the proportion of population biomass to total community aboveground biomass (PPB) and the relationship between them in S. bungeana were examined to investigate the effects of stocking rate, nitrogen addition and their interaction.

Important findings As the stocking rate increased, the plant height, canopy diameter, tiller density, seedlings, aboveground biomass, and PPB all followed a “single peak” curve trend, while the population density decreased. Nitrogen addition increased the plant height, canopy diameter, reproductive branch density, tiller density, aboveground biomass and PPB, while density of seedlings initially increased and then decreased as the nitrogen addition levels rose. The total effect of grazing on population aboveground biomass and the PPB was small compared with that of nitrogen addition. Specifically, grazing had a direct negative effect on aboveground biomass and affected PPB by regulating tiller density, population density and aboveground biomass. Nitrogen addition had a positive effect on aboveground biomass, both directly and indirectly through increasing plant height, reproductive branch density. It also impacted the PPB through regulating population density, canopy diameter, tiller density, and reproductive branch density. Overall, nitrogen addition increased canopy diameter and reproductive branch density and grazing increased density of seedings. The interaction of grazing and nitrogen addition significantly affected reproductive branch density. Stipa bungeana had maximum aboveground biomass or community status at a stocking rate of 4.10 or 5.29 sheep·hm-2. These results indicated that grazing and nitrogen addition regulated the aboveground biomass and community status of S. bungeana through affecting its morphological characteristics, providing a basis for the scientific management and sustainable development of grassland populations.

Key words: grazing, nitrogen addition, population, morphological traits, aboveground biomass, community status