Effects Of Different Nitrogen Regulation Measures On Nitrogen Transformation And Greenhouse Gas Emission In Wheat Field

Farmland ecosystem is the important source or sink of greenhouse gases in the atmosphere.The effects of greenhouse gas emissions caused by agricultural production activities on global warming had become increasingly significant and won widespread attention while fertilization was an important factor affecting farmland greenhouse gas emissions.The study of farmland greenhouse gas emissions under different nitrogen regulations measures and extracting new patterns which could reduce emission and the negative effects of nitrogen played an important role to the sustainable development of farmland ecosystem and slowing global warming process.In this study,we planted wheat in field plots as experimental material and set up four nitrogen regulation measures,respectively,U+HQ,U+DCD,U+HQ+DCD and PCU in contrast with U.Then,we explored the effects of different nitrogen fertilizer regulation measures on soil nitrogen transformation in the wheat field,greenhouse gas emissions and yield.The results showed that:（1）U+HQ,U+DCD,U+HQ+DCD and PCU in different nitrogen regulation measures can raise the concentration of ammonium nitrogen,reduce nitrate concentration and slow down apparent nitrification rate.（2）Urease inhibitors and nitrification inhibitors can reduce soil urease activity,while the inhibitory effect of U+HQ pattern is the most obvious.In these four nitrogen regulation measures,Only PCU can significantly improve the activity of sucrose and the peak of urease activity was 0.58 mg glucose g-1 h-1.（3）All four nitrogen measures had the effect of reduce N₂ O emission.The N₂ O emission fluxof U+DCD and U+HQ+DCD was less than U in the entire test.CO₂ flux peak showed the trend: U>U+DCD>U+HQ+DCD>U+HQ>PCU.U+HQ,U+HQ+DCD and PCU were significantly decreased the accumulation of CO₂ emission,The CO₂ emission reduction effect of U+DCD did not reach a significant level（P<0.05）.The most accumulation absorption of CH4 occurred in U,and the absorption of the other nitrogen measures was significantly lower than U（P<0.05）.（4）Different nitrogen measures could significantly improved the wheat ears（P<0.05）.The 1000-grain weight showed U>U+HQ>U+DCD>U+HQ+DCD>PCU with no significant difference（P<0.05）.Wheat yields of U+DCD and PCU were respectively 1.04 and 1.01 times of U.U+HQ+DCD caused a 9.91% decrease of wheat production and U+HQ also caused decrease at a not significant difference level（P < 0.05）.Different nitrogen fertilizer regulation measures reduced global warming potential and greenhouse gases emission intensity significantly（P<0.05）,in which PCU had the strongest effects.（5）U+DCD and PCU had obvious advantages than U considering effects of different nitrogen fertilizer regulation measures on soil nitrogen transformation,greenhouse gas emissions and wheat yield.In the future,fertilizer with nitrification inhibitor and coated urea nitrogen control measures could be used in the process of agricultural production.