Nitrogen fertilizers are not effective in reducing nitrous oxide emissions from drip-irrigated cotton fields
Agriculture is the major source of greenhouse gas nitrous oxide (N2O) emissions. Application of polymer-coated urea and urease and/or nitrification inhibitor has the potential in reducing soil N2O emissions.
Drip irrigation is an effective water-saving strategy for crop production in arid regions. However, limited information is available on how fertilizer nitrogen (N) management affects soil N2O emission under drip irrigation.
Researchers from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences found that enhanced-efficiency nitrogen fertilizers were not effective in reducing N2O emissions from drip-irrigated cotton fields in arid northwest China.
They carried out a two-year cotton field experiment in Xinjiang to determine N2O emissions from different fertilizer N sources (urea, polymer-coated urea-ESN, stabilized urea with nitrification and urease inhibitors-SuperU) and rates (120 and 240 kg N ha-1).
Results showed that N2O emissions over a two-year growth season were significantly increased by 29-47% in treatment of ESN or SuperU, without significant effect on cotton yield. Reducing the N rate by half significantly reduced both the N2O emissions and cotton yield.
The efficiency of ESN and SuperU is limited, and fertigation with urea at recommended rate is the best option to ensure cotton yield and mitigation in N2O emission in this study site, according to the study.
The study was published in Science of The Total Environment.