Ecosystems

, Volume 17, Issue 4, pp 657–672

Effects of Multi-nutrient Additions on GHG Fluxes in a Temperate Grassland of Northern China

Article

DOI: 10.1007/s10021-014-9750-z

Cite this article as:
Zhang, L., Huo, Y., Guo, D. et al. Ecosystems (2014) 17: 657. doi:10.1007/s10021-014-9750-z

Abstract

Human activities have substantially enhanced the availability of important nutrient elements such as nitrogen (N), phosphorus (P), and potassium (K) in ecosystems worldwide. However, how the concurrent increase in all of these nutrients will affect greenhouse gas (that is, CO2, N2O, CH4) levels remains unknown. In a temperate steppe of northern China, a 2-year field experiment was conducted to examine the effects of multi-nutrient additions on GHG fluxes from 2009 to 2010. Four levels of annual nutrient loads were mimicked: 0 g NPK (control), 15.5 g P m−2 and 19.5 g K m−2 as KH2PO4 (PK), 10 g N m−2 as NH4NO3 plus PK (10N + PK), and 20 g N m−2 plus PK (20N + PK) per year. The results show that multi-nutrient additions led to significant increases in net primary production (NPP) and soil temperature (ST), a significant decrease in soil moisture (SM) in 2010, and no significant changes in other soil parameters. Seasonal patterns differed greatly for different GHG fluxes in response to different nutrient treatments, largely as a result of differences in influential factors. The 10N + PK treatment significantly increased CO2 uptake, whereas the 20N + PK treatment significantly decreased CO2 uptake. The application of P and K without additional N significantly enhanced CH4 uptake, whereas the two N + PK treatments significantly enhanced N2O emissions. Significant positive, linear relationships were found between cumulative CO2 uptake and soil total nitrogen (TN), microbial biomass carbon, and microbial biomass nitrogen, whereas significant negative, linear relationships were found with NPP, SM, and the C/N ratio. Significant positive, linear relationships were found between cumulative N2O emission and ST, TN, NPP, and total organic carbon, whereas no relationships were found between cumulative CH4 uptake and any soil parameters. CO2 flux was related to N2O flux temporally, to a certain extent, for all the treatments. In the control, N2O flux showed a negative, linear relationship with CH4 flux, whereas no regular relationships were detected between CO2 and CH4 fluxes in any treatment. Our findings imply that increasing nutrient deposition will change the magnitude, patterns, and relationships among GHG uptakes and emissions in the future.

Keywords

Nitrogen Phosphorus Potassium Net primary production Soil temperature Soil moisture Soil microbial carbon and nitrogen GHGs 

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.State Key Laboratory of Vegetation and Environmental Change, Institute of BotanyChinese Academy of SciencesBeijingChina
  2. 2.Shandong Normal UniversityJinanChina
  3. 3.Inner Mongolian UniversityHuhhotChina

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