Chin J Plant Ecol ›› 2021, Vol. 45 ›› Issue (3): 309-320.DOI: 10.17521/cjpe.2020.0264

• Research Articles • Previous Articles    

Soil enzyme activities and their influencing factors in a desert steppe of northwestern China under changing precipitation regimes and nitrogen addition

ZHU Wan-Wan1,2, WANG Pan2, XU Yi-Xin2, LI Chun-Huan2, YU Hai-Long2, HUANG Ju-Ying1,*()   

  1. 1School of Ecology and Environmental Sciences, Ningxia University, Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwestern China, Key Laboratory for Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan 750021, China
    2School of Geography Science and Planning, Ningxia University, Yinchuan 750021, China
  • Received:2020-08-03 Accepted:2020-12-22 Online:2021-03-20 Published:2021-05-17
  • Contact: HUANG Ju-Ying
  • Supported by:
    Project of First-Class Discipline Construction (Ecology) for Ningxia Higher Education(NXYLXK2017B06);National Natural Science Foundation of China(31760144);National Natural Science Foundation of China(41961001)


Aims Soil enzymes, which are mainly produced by plant roots and soil microbes, involve in the organic matter degradation and element cycling and other key processes in plant-soil systems. Study on the relationships between soil enzyme activity and plant community composition and microbial activity under changing precipitation pattern and increasing nitrogen (N) deposition can provide a new insight for evaluating the influencing mechanism of global change on the biogeochemical cycling in plant-soil systems.
Methods Based on a field experiment involving five precipitation treatments (50% reduction, 30% reduction, natural precipitation, 30% increase, and 50% increase) and two N addition treatments (0 and 5 g·m-2·a-1) conducted in a desert steppe of Ningxia since 2017, the changes of soil enzyme activities (sucrase, urease, and phosphatase) were studied and their relationships with plant community composition and microbial ecological stoichiometry were analyzed in 2018 and 2019.
Important findings Compared with decreasing precipitation, increasing precipitation had greater impacts on the three enzyme activities, but its effects were interacted with N addition and sampling year. Increasing precipitation had no significant impacts on the three enzyme activities in 2018, but enhanced them in 2019. By contrast, N addition had less influences on the three enzyme activities, especially in 2019. The biomass of Astragalus melilotoides was negatively correlated with urease and phosphatase activities, while the biomass of Cleistogenes squarrosa had positive correlation with the three enzyme activities. Except the Patrick richness index, plant community diversity indices were generally negatively correlated with the three enzyme activities. Soil enzyme activities were more greatly affected by soil pH, soil total phosphorus (P), and microbial biomass carbon (C):N:P. Therefore, short-term precipitation change and N addition have little effects on the soil enzymes in the studied desert steppe (especially under reducing precipitation); increasing precipitation and N addition could pose direct influences on soil enzyme activities by increasing plant biomass, changing plant diversity, regulating microbial biomass ecological stoichiometry, and enhancing soil P availability. Given the diversity and functional complexity of soil enzymes, it is necessary to deeply analyze the influencing mechanism of global change on enzyme activities by measuring the long-term responses of various enzyme activities.

Key words: arid and semi-arid region, changing precipitation regimes, increasing atmospheric nitrogen deposition, microbial ecological stoichiometry, plant community diversity