Effects of Corn Stalks and Urea on N<sub>2</sub>O Production from Corn Field Soil
2021
Kaikuo Wu | Zhe Zhang | Liangshan Feng | Wei Bai | Chen Feng | Yuchao Song | Ping Gong | Yue Meng | Lili Zhang
Returning corn stalks to the field is an important and widely used soil management practice which is conducive to the sustainable development of agriculture. In this study, the effects of corn stalks and urea on N<sub>2</sub>O production in corn field soil were investigated through a 21-day incubation experiment. This study showed that increasing amounts of urea added to soil with a history of corn cultivation leads to increasing overall N<sub>2</sub>O emissions, by increasing both the intensity and the duration of emissions. Although N<sub>2</sub>O production was affected primarily by urea-derived NH<sub>4</sub><sup>+</sup>-N and NO<sub>3</sub><sup>−</sup>-N, its main source was native soil nitrogen, which accounted for 78.5 to 94.5% of N<sub>2</sub>O. Returning corn stalk residue to the field reduced the production of N<sub>2</sub>O, and the more urea was applied, the stronger the effect of corn residue on reducing N<sub>2</sub>O emissions. Combining the application of corn stalks and urea could reduce the concentration of NH<sub>4</sub><sup>+</sup>-N and NO<sub>3</sub><sup>−</sup>-N derived from urea, and then reduce the substrate required for N<sub>2</sub>O production in nitrification and denitrification processes. In addition, the combined application of corn stalks and urea could effectively inhibit the abundance of key N<sub>2</sub>O-producing genes AOA <i>amoA</i>, <i>nirS</i> and <i>nirK</i>.
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