Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (6): 882-894.DOI: 10.17521/cjpe.2022.0031

• Research Articles • Previous Articles    

Effects of freeze-thaw changes on soil physicochemical properties and enzyme activities in root zone of Picea asperata and Fargesia nitida under subalpine forests of southwest China

GUO Min1, LUO Lin2, LIANG Jin2, WANG Yan-Jie1,*(), ZHAO Chun-Zhang3,*()   

  1. 1College of Life Science, Sichuan Normal University, Chengdu 610100, China
    2Chengdu Institute of Biology, Chinese Academy of Sciences, CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu 610041, China
    3College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China
  • Received:2022-01-18 Accepted:2022-05-20 Online:2023-06-20 Published:2022-06-09
  • Contact: * (Wang YJ,;Zhao CZ,
  • Supported by:
    National Natural Science Foundation of China(31570477);National Natural Science Foundation of China(31700418);Science and Technology Plan Projects in Sichuan Province(21ZDYF0754)


Aims The subalpine forests of southwest China belongs to a typical seasonal frozen soil area. This study aimed to explore the effects of freeze-thaw changes on the soil physicochemical properties and enzyme activities under forest soils in response to climate warming.

Methods Infrared radiation heaters were applied to simulate climate warming. Soils in the root zone of Picea asperata and Fargesia nitida were collected to explore the effects of warming on soil freeze-thaw cycles, soil physicochemical properties and enzyme activities. Meanwhile, soil incubation experiments were conducted to further analyze the effects of different freeze-thaw cycles on soil properties.

Important findings Our results showed that (1) Experimental warming increased the soil temperatures by 2.85 and 2.13 °C, decreased freezing days by 60 and 32 days, and also declined freeze-thaw cycles from 1-3 times to 0 time at the 5 cm and 15 cm soil depths, respectively. (2) Warming increased the contents of soil total nitrogen (TN), dissolved organic nitrogen (DON) and microbial biomass nitrogen (MBN), but significantly reduced the content of ammonium nitrogen (NH4+-N) under both P. asperata and F. nitida plots. The soil freezing days and number of freeze-thaw cycles were significantly negatively correlated with TN and DON contents, and significantly positively correlated with NH4+-N content. (3) Warming significantly promoted the activity of β-N-acetylglucosaminidase (NAG), but significantly inhibited the activity of urease (Ure) under the root zone soil of the two species. The activities of NAG and Ure were significantly correlated with freezing days and the number of freeze-thaw cycles. (4) Similar to results of the field study, the simulated freeze-thaw cycles significantly increased NH4+-N content and 4-methylumbelliferyl-β-D-glucoside (BG) activity, but decreased NAG activity under the root zone soil of P. asperata. On the other hand, freeze-thaw cycles increased NH4+-N content and reduced the activities of NAG and BG under the root zone soil of F. nitida. However, the effects of freeze-thaw cycles on the contents of nitrate nitrogen (NO3--N) and DON as well as the activities of Ure and protease (Pro) were different based on the results of field experiment. Redundancy analysis showed that soil enzyme activities under the root zone of F. nitida were mainly affected by DON content, whereas those parameters under the root zone of P. asperatawere significantly correlated with pH, NH4+-N and DON contents. These results suggested that the disappearance of freeze-thaw cycles caused by future climate warming would significantly affect the soil physicochemical properties (especially soil nitrogen pool) and enzyme activities during non-growing season under subalpine forests of southwest China. But the underlying mechanism needs further study.

Key words: freeze-thaw cycle, simulated warming, Picea asperata, Fargesia nitida, soil physicochemical property, enzyme activity