Chin J Plant Ecol ›› 2019, Vol. 43 ›› Issue (2): 165-173.DOI: 10.17521/cjpe.2018.0267

• Research Articles • Previous Articles     Next Articles

Effects of nitrogen and phosphorus additions on nitrous oxide emissions from alpine grassland in the northern slope of Kunlun Mountains, China

CAO Deng-Chao1,2,3,4,GAO Xiao-Peng1,2,3,*(),LI Lei1,2,3,GUI Dong-Wei1,2,3,ZENG Fan-Jiang1,2,3,KUANG Wen-Nong1,2,3,4,YIN Ming-Yuan1,2,3,4,LI Yan-Yan1,2,3,4,Aili PULATI5   

  1. 1 Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, ürümqi 830011, China
    2 Cele National Station of Observation and Research for Desert-Grassland Ecosystems in Xinjiang, Cele, Xinjiang 848300, China
    3 Key Laboratory of Biogeography and Bio-resource in Arid Zone, Chinese Academy of Sciences, ürümqi 830011, China
    4 University of Chinese Academy of Sciences, Beijing 100049, China
    5 Cele Grassland Management Station in Xinjiang, Cele, Xinjiang 848300, China
  • Received:2018-10-30 Accepted:2019-02-01 Online:2019-02-20 Published:2019-06-04
  • Contact: GAO Xiao-Peng
  • Supported by:
    Supported by the National Natural Science Foundation of China(31570002);Supported by the National Natural Science Foundation of China(31870499)

Abstract: <i>Aims</i>

Nutrient additions such as nitrogen and phosphorus are important strategies to improve the productivity of the grassland ecosystem. However, their effect on soil nitrous oxide (N2O) emissions remains unclear.

<i>Methods</i>

A field study was conducted in an alpine grassland located in the north slope of Kunlun Mountains in Southern Xinjiang. Four treatments included nitrogen addition alone (N), phosphorus addition alone (P), mixture of nitrogen and phosphorus additions (N + P) and an unfertilized control (CK). Gas samples were collected and analyzed using the static chamber chromatography methodology during the 2017 growing season. Treatment effects on the characteristics of N2O emissions from grassland soil were thoroughly investigated. Pearson correlation analysis was used to identify and quantify the influence of environmental variables on soil N2O emissions.

<i>Important findings</i>

The results showed that N and (N + P) treatments induced N2O flux peaks after three weeks of fertilizer addition, with the maximum daily N2O flux rates of 42.3 and 15.4 g N·hm -2·d -1, respectively. The N treatment significantly increased growing season cumulative N2O emissions by 1.8 to 3.2 times compared to P treatment, (N + P) treatment and CK, and there were no significant differences between the three treatments. Pearson correlation analysis showed that daily N2O flux rate was correlated negatively with soil microbial biomass carbon, and positively with soil pH and dissolved organic carbon. There was no significant correlation between daily N2O flux rate and other environmental variables. These results suggest that simultaneous addition of nitrogen and phosphorus nutrients can significantly reduce soil N2O emission compared to N treatment for the alpine grassland in this region.

Key words: alpine grassland, nitrogen and phosphorus addition, N2O, Kunlun Mountains, flux characteristic