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Chinese Agricultural Science Bulletin ›› 2023, Vol. 39 ›› Issue (26): 98-108.doi: 10.11924/j.issn.1000-6850.casb2022-0760

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Effects of Biochar Combined with Silicate Fertilization on CH4 and N2O Emission Intensity in Rice-wheat Rotation Field under Nighttime Warming

ZHU Mengquan1,2(), LOU Yunsheng1,2(), DU Zeyun2, GAO Anni2, PAN Defeng2, GUO Junhong2   

  1. 1 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044
    2 Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044
  • Received:2022-09-01 Revised:2022-11-05 Online:2023-09-15 Published:2023-09-11

Abstract:

One of the main characteristics of climate warming is that the nighttime warming is larger than the daytime warming. The effect of nighttime warming, silicate application or biochar addition on the production of single crop (rice or wheat) was available, but the coupled effects of the three factors on the emission intensity of CH4 and N2O in rice-wheat rotation field were still unclear. A field simulation experiment was conducted to investigate the effects of biochar with silicate supply on the yield of rice and wheat, CH4 and N2O emission under nighttime warming. An orthogonal experimental design with three-factor and three-level was adopted in this study. The rice and wheat canopy was covered with aluminum foil to simulate nighttime warming (19:00—6:00). Nighttime warming was set at 3 levels, i.e. W0 (ambient temperature, control), W1 (covered with 5 mm aluminum foil film) and W2 (covered with 11 mm aluminum foil film); biochar was amended at 3 levels, i.e. B0 (control), B1 (10 t/hm2 biochar) and B2 (25 t/hm2 biochar); silicate fertilizer was added at 3 levels, i.e. control (Si0), Si1 (steel slag powder at 0.2 t SiO2/hm2) and Si2 (mineral powder at 0.2 t SiO2/hm2). The results showed that the yield of rice and wheat decreased under nighttime warming, but obviously increased with biochar amendment. Nighttime warming, applying mineral powder and biochar inhibited the cumulative emission of CH4, and reduced the total warming potential (SGWP) and greenhouse gases (CH4 and N2O) intensity (GHGI) in rice-wheat field. The rice production contributed more to the SGWP than wheat production, and CH4 emission played a dominant role in the SGWP. Effects of the three factors on the SGWP and the GHGI in rice field were in the sequence of B>Si>W, and in the order of Si>B>W in wheat field. This study suggested that applying 0.2 t/hm2 mineral powder and 25 t/hm2 biochar were the best treatment (factor combination) to stabilize rice and wheat production, and simultaneously reduced the emission of CH4 and N2O under nighttime warming.

Key words: nighttime warming, biochar, silicate, rice-wheat rotation, GHGI