Chin J Plant Ecol ›› 2025, Vol. 49 ›› Issue (5): 697-709.DOI: 10.17521/cjpe.2023.0397  cstr: 32100.14.cjpe.2023.0397

Special Issue: 草原与草业

• Research Articles • Previous Articles     Next Articles

Effects of extreme precipitation on soil gross nitrification rate, gross nitrogen mineralization rate and sensitivity of different types of grassland

HAN Fei1,2,3, WANG Ge1,2,3, WU Shuai-Kai1,2,3, LIN Mao1,2,3, DONG Kuan-Hu1,2,3, $\boxed{\hbox{WANG Chang-Hui}}$ 1,2,3,*, SU Yuan1,2,3,*()   

  1. 1College of Grassland Science, Shanxi Agricultural University, Taigu, Shanxi 030801, China
    2Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation, Taigu, Shanxi 030801, China
    3and Youyu Loess Plateau Grassland Ecosystem National Research Station, Youyu, Shanxi 037200, China
  • Received:2023-12-29 Accepted:2024-05-22 Online:2025-05-20 Published:2025-04-14
  • Contact: $\boxed{\hbox{WANG Chang-Hui}}$ , SU Yuan
  • Supported by:
    National Natural Science Foundation of China(U22A20576);National Natural Science Foundation of China(32371670);National Key R&D Program of China(2022YFF1302801);Platform Special Project of Shanxi Provincial Department of Science and Technology(202104010910017)

Abstract:

Aims In the context of global climate change, frequent extreme precipitation events will affect the soil nitrogen transformation processes in the semi-arid steppe. However, it remains unclear how the key processes of soil nitrogen transformation respond to precipitation change and how the total nitrogen mineralization rate is sensitive to different precipitation levels.

Methods This study was conducted on the meadow steppe, typical steppe, and desert steppe of the Global Change Network test platform of the northern China Steppe. In this study, the gross nitrogen mineralization rate (GNM) and gross nitrification rate (GN) of soil were measured by the 15N isotopic pool dilution method, as well as related biological (microbial biomass carbon content, microbial biomass nitrogen content, background biomass (BGB)), and abiotic (soil temperature (ST), soil water content (SWC)), soil substrate (soil ammonium nitrogen (NH4+-N) content, nitrate nitrogen (NO-3-N) content, soluble organic carbon content, soluble organic nitrogen content) indexes.

Important findings The results showed significant differences in GNM among different steppe types. The highest GNM was in meadow steppe ((3.284 ± 0.613) mg·kg-1·d-1), followed by typical steppe ((1.370 ± 0.167) mg·kg-1·d-1) and desert steppe ((0.724 ± 0.216) mg·kg-1·d-1). However, the 50% decrease in precipitation had no significant effects on the GNM and GN of the three grasslands. The sensitivity of GNM and GN to precipitation reduction in typical steppe and desert steppe soil was significantly higher than that of precipitation increase. In contrast, the sensitivity of GNM and GN in meadow steppe soil was not significantly different between precipitation increase and decrease. Structural equation model (SEM) analysis revealed that SWC was the main factor affecting the soil GNM. These results indicate that short-term extreme precipitation has no significant effects on the GNM and GN of three important grasslands in northern China, but changes their sensitivity to precipitation change. How the increase of extreme precipitation events will affect the soil nitrogen conversion process in terrestrial ecosystems in the future needs to be systematically studied over long time scales and large spatial patterns.

Key words: northern grassland, gross nitrogen mineralization, extreme precipitation, sensitivity, soil moisture