Journal of Resources and Ecology ›› 2019, Vol. 10 ›› Issue (2): 147-154.DOI: 10.5814/j.issn.1674-764X.2019.02.005

• Grassland Ecosystem • Previous Articles     Next Articles

Soil Priming Effect Mediated by Nitrogen Fertilization Gradients in a Semi-arid Grassland, China

LI Yue1, NIE Cheng1, SHAO Rui2, DU Wei1, LIU Yinghui1,*   

  1. 1. State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
    2. Department of Geography, Ghent University, Ghent 9000, Belgium
  • Received:2018-10-17 Accepted:2018-12-20 Online:2019-03-30 Published:2019-03-30
  • Contact: LIU Yinghui
  • Supported by:
    National Natural Science Foundation of China (31770519);National Key Research and Development Program of China (2017YFC0503805).

Abstract:

The priming effect is well acknowledged in soil systems but the effect of nitrogen (N) fertilization remains elusive. To explore how N modifies the priming effect in soil organic matter (SOM), one in situ experiment with 13C labeled glucose addition (0.4 mg C g-1 soil, 3.4 atom % 13C) was conducted on soil plots fertilized with three gradients of urea (0, 4 and 16 g N m-2 yr-1). After glucose addition, the soil CO2 concentration and phospholipid fatty acid (PLFA) were measured on day 3, 7, 21 and 35. The study found that N fertilization decreased soil CO2, PLFA and the fungi to bacteria ratio. Glucose triggered the strongest positive priming in soil at 0 g N m-2 yr-2, meanwhile N fertilization decreased SOM-derived CO2. Soil at 4 g N m-2 yr-2 released the largest amount of glucose-derived carbon (C), likely due to favorable nutrient stoichiometry between C and N. Stable microbial community biomass and composition during early sampling suggests “apparent priming” in this grassland. This study concludes that N fertilization inhibited soil priming in semi-arid grassland, and shifted microbial utilization of C substrate from SOM to added labile C. Diverse microbial functions might be playing a crucial role in soil priming and requires attention in future N fertilization studies.

Key words: nitrogen fertilization, 13C labeled glucose, soil priming effect, phospholipid fatty acids, semi-arid grassland