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| Emission intensity of CH4 and N2O under simulated low light with different colour shading net in paddy field |
| Received:September 08, 2024 |
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| KeyWord:low light stress;rice;methane;nitrous oxide;greenhouse gases emission intensity |
| Author Name | Affiliation | E-mail | | ZHU Jinlong | Jiangsu Provincial University Key Laboratory of Agricultural and Ecological Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China
School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | LUO Yongting | School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | GAO Zeyu | School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | SHI Yuqing | School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | ZHU Qichun | School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | | | LOU Yunsheng | Jiangsu Provincial University Key Laboratory of Agricultural and Ecological Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China
School of Ecology and Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China | yslou@nuist.edu.cn |
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| Abstract: |
| In order to cope with the global climate change, the low light stress caused by extreme cloudy and rainy weather during the rice growing period has limited the sustainable production of rice in the middle and lower reaches of the Yangtze River of China. This study explores which color shading net can better simulate the low light environment, and what impact on rice production, CH4 and N2O emissions from rice field. The single factor randomized experimental design was adopted in this study. The shading treatment was set as follows：C0 （control, no shading）, C1（canopy covered with black shading net）, C2（canopy covered with silver grey shading net）, and C3（canopy covered with white shading net）, with the average shading rate being 60%. The results showed that, the differences existed in the spectral composition（light quality）on rice canopy under different shading treatments, i. e., in C1 treatment, the ratio of red and blue light to photosynthetic active radiation（PAR）changes slightly, and the ratio of red light to infrared（R/FR）decreased 1.81%; in C2 treatment, the ratio of red light to PAR decreased 1.39%, the ratio of blue light to PAR increased 1.09%, and the R/FR ratio decreased 1.96%, with similar properties to that under rainy weather; in C3 treatment, the ratio of red light to PAR increased 5.54%, the ratio of blue light to PAR decreased 5.92%, and the R/FR ratio decreased 7.2%. The changes in PAR, the ratio of red, blue and green light to PAR in C2 treatment were positively correlated with that under cloudy and rainy weather. Compared with C0 treatment, three shading treatments significantly reduced the shoot biomass during the jointing-flowering period, C1 and C2 treatments significantly reduced the dry matter translocation and translocation rate by 77%, 66.4%, and 70.8%, 58.1%, respectively; C1, C2 and C3 significantly decreased rice yield by 65.7%, 25.7% and 33.3%, respectively. In comparison with C0, shading（C1, C2 and C3）significantly decreased CH4 emission flux, but increased N2O emission flux. Compared to C0, C1, C2 and C3 significantly reduced the cumulative CH4 emission in the field by 76.2%, 85.2%, and 76.0%, respectively; while obviously increased the cumulative N2O emission by 19.1%, 106.4% and 295.0%, respectively. C1, C2 and C3 significantly reduced the global warming potential（GWP）and the emission intensity of CH4 and N2O（GHGI）in the field, with GWP decreasing by 75.6%, 87.8%, and 74.2%, and GHGI reducing by 7.3%, 83.4%, and 56.4%, respectively. The yield was significantly correlated with PAR. The contribution of CH4 emission to the GWP was significantly correlated with the ratio of green light to PAR, and the contribution of N2O emission to the GWP was significantly correlated with the ratio of red, blue, green light to PAR, and R/FR ratio. This study suggests that the simulated low light with different color shading nets significantly reduced the yield, and the GHGI in the paddy field. Silver gray shading net was the better choice for simulating low light environments induced by cloudy and rainy weather, and for accurately evaluating the GHGI in rice fields under low light conditions. |
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