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Chinese Journal of Applied Ecology ›› 2021, Vol. 32 ›› Issue (7): 2389-2396.doi: 10.13287/j.1001-9332.202107.009

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Effects of precipitation change and nitrogen addition on soil net N mineralization in a saline-alkaline grassland of Northern Shanxi Province, China

WANG Yan1,2, DIAO Hua-jie2,3,4, DONG Kuan-hu3,4, WANG Chang-hui2,3,4, ZHAO Wei1*   

  1. 1College of Agriculture, Henan Univer-sity of Science and Technology, Luoyang 471023, Henan, China;
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;
    3College of Grassland Science, Shanxi Agricultural University, Jinzhong 030801, Shanxi, China;
    4Youyu Loess Plateau Grassland Ecosystem Research Station, Youyu 037200, Shanxi,China
  • Received:2021-02-19 Revised:2021-03-20 Online:2021-07-15 Published:2022-01-15
  • Contact: *zhaowei1@haust.edu.cn
  • Supported by:
    National Natural Science Foundation of China (31770526) and the National Key R&D Program of China (2017YFA0604802).

Abstract: To explore the responses of soil net nitrogen (N) mineralization rate to precipitation varia-tion and nitrogen deposition in salinized grassland, we set precipitation manipulation and nitrogen addition experiments in the typical agro-pastoral ecotone saline-alkaline grassland of Northern Shanxi Province, China. The in situ soil net N mineralization rate was determined by top-cover buried PVC cylinder from May to September in 2019. The results showed that there were seasonal dynamics in soil net N mineralization rate. Soil net N mineralization rate was not affected by increase/decrease precipitation (±50%), nitrogen addition (10 g·m-2·a-1) or the combination of nitrogen addition and increase 50% precipitation treatments. The combination of nitrogen addition and 50% reduction of precipitation significantly improved soil net nitrification rate and net N mine-ralization rate by 10.8 and 8.6 times, respectively. Soil net nitrogen mineralization rate was positively related to soil water content, and negatively related to soil pH. The effects of nitrogen addition on soil nitrogen mineralization rate were dependent on precipitation conditions. Soil water content and pH were important factors regulating soil net nitrogen mineralization rate in the saline-alkaline grassland of Northern Shanxi Province. Therefore, to roundly assess the response model of soil N mine-ralization process to global change, it is necessary to consider the interaction of precipitation changes and nitrogen addition, and the soil physical and chemical properties of salinized grassland.

Key words: net nitrogen mineralization, saline-alkaline grassland, precipitation change, nitrogen addition