Chin J Plant Ecol ›› 2024, Vol. 48 ›› Issue (4): 523-533.DOI: 10.17521/cjpe.2022.0346

• Research Articles • Previous Articles     Next Articles

Temperature sensitivity of soil net nitrogen mineralization rates across different grassland types

WANG Ge1,*, HU Shu-Ya2, LI Yang2, CHEN Xiao-Peng1, LI Hong-Yu1, DONG Kuan-Hu1, HE Nian-Peng3, WANG Chang-Hui1,2,**   

  1. 1College of Grassland Science, Shanxi Agricultural University, Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation, Taigu, Shanxi 030801, China
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    3Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2022-08-25 Accepted:2023-02-20 Online:2024-04-20 Published:2024-05-11
  • Contact: **
  • Supported by:
    Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23080402);National Key R&D Program of China(2017YFA0604802);Second Tibetan Plateau Scientific Expedition and Research (STEP) Program(2019QZKK0606);Key Laboratory Program of Shanxi Province(202104010910017)

Abstract:

Aims Soil available nitrogen (N), generated from a series of soil mineralization processes, is a major limiting factor of terrestrial ecosystem productivity. Soil N availability depends on soil microorganisms, vegetation types, and soil physical and chemical properties. Soil microorganisms are very sensitive to environmental changes, especially the temperature change, which is closely related with microbial growth and reproduction. Therefore, it is important to understand the temperature sensitivity (Q10) of microbial regulation of N mineralization rates in a large spatial scale for predicting the impacts of global climate changes on terrestrial ecosystem productivity.
Methods Three types of grasslands (namely meadow steppe, typical steppe, and desert steppe) were selected in Nei Mongol Plateau, Loess Plateau, and Qingzang Plateau, respectively. Soil net N mineralization rates were measured at different temperatures in the laboratory, and then Q10 of N mineralization rates were calculated across different grassland types. Relative parameters, including soil microbe, soil physical and chemical properties, were also analyzed.
Important findings (1) The highest Q10 of soil net N mineralization rates was found in all of three grassland types of Loess Plateau than those of Nei Mongol and Qingzang Plateaus. (2) The Q10 values of soil net N mineralization rates in the meadow steppes and typical steppes on the Loess Plateau and Nei Mongol Plateau were significantly higher than those in the desert steppes, while on the Qingzang Plateau, the values in the alpine meadow steppes were significantly lower than that in the alpine typical steppes and alpine desert steppes. (3) Q10 values of soil net N mineralization rates was closely correlated with soil microbial biomass carbon content across different grassland types. (4) The spatial pattern of Q10 is jointly regulated by microorganisms, soil texture and substrate. The results of this study provide important data for understanding of the response of soil N cycle to global change in different grassland types in China, which is valuable for optimization of N cycle models of terrestrial ecosystems in the future.

Key words: ammonia-oxidizing microorganisms, microbial biomass carbon, microbial biomass nitrogen, net nitrogen mineralization rate, temperature sensitivity (Q10)