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.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 10 • No. 2