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| DOI：10.13522/j.cnki.ggps.2017.0321 |
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| CH4 and N2O Emission from Paddy Field in Cold Region is Impacted by Irrigation Methods |
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WANG Changming, ZHANG Zhongxue, LYU Chunbo, ZHENG Ennan, YUN Ninghan
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1. School of Water Conservancy & Civil Engineering, Northeast Agricultural University, Harbin 150030, China; 2.Water Conservancy Management Center of Heilongjiang, Harbin 150001, China
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| Abstract: |
| 【Objective】Microbial activities involved in biochemical reactions that emit greenhouse gases are modulated by soil moisture and the purpose of this paper is to examine how irrigations affect these biochemical processes in paddy field with a view to provide a guidance for managing paddy filed in cold region in Heilongjiang province. 【Method】The field experiment compared three irrigation methods: control irrigation, intermittent irrigation and flood irrigation. In each treatment, we measured the change in CH4 and N2O emission, as well as their warming potential using the static chamber-gas chromatograph technique.【Result】①In all treatments, CH4 emitted mainly during the tillering booting and flowering stages. Compared to flood irrigation, control and intermittent irrigation both significantly reduced CH4 emission (P<0.01), with the control irrigation reducing by 56.29% and the intermittent irrigation by 26.59%. ②The drying period during the dry-wet alternation and one week after the third nitrogen fertilization were the main emission period of N2O, and there was a negative N2O emission during the seeding establishment period. The N2O emission in control irrigation peaked after the third nitrogen fertilization, which was six days earlier than the time it peaked under the intermittent and flood irrigation. Compared with flood irrigation, the control and intermittent irrigation increased N2O emission by 55.6% and 56.0% respectively. ③There was a significant correlation between CH4 emission and 5 cm soil temperature under flooded irrigation (P<0.01), while under control irrigation the N2O emission was significantly correlated with 15 cm soil temperature (P<0.01). Soil temperature profile and atmospheric temperature combined to significantly affect CH4 and N2O emission under intermittent irrigation, while CH4 and N2O emissions under flood irrigation was significantly regulated by soil temperature. 【Conclusion】Irrigations do affect CH4 and N2O emission from paddy field in cold region, and our results showed that control irrigation not only reduces the warming potential but also increases grain yield. |
| Key words: paddy field; irrigation; greenhouse gas emission; global warming potential |
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