• ISSN 1008-505X
  • CN 11-3996/S
ZHONG Jia-wang, ZHANG Li, ZHAN Xiang-sheng, LIU Rong, DONG Qin-ge, ZHANG Man, FENG Hao. Pyrolysis temperature and nitrogen application rate influence the effects of biochar on greenhouse gas emission reduction and spring maize yield[J]. Journal of Plant Nutrition and Fertilizers, 2023, 29(4): 664-676. DOI: 10.11674/zwyf.2022493
Citation: ZHONG Jia-wang, ZHANG Li, ZHAN Xiang-sheng, LIU Rong, DONG Qin-ge, ZHANG Man, FENG Hao. Pyrolysis temperature and nitrogen application rate influence the effects of biochar on greenhouse gas emission reduction and spring maize yield[J]. Journal of Plant Nutrition and Fertilizers, 2023, 29(4): 664-676. DOI: 10.11674/zwyf.2022493

Pyrolysis temperature and nitrogen application rate influence the effects of biochar on greenhouse gas emission reduction and spring maize yield

  • Objective We studied the effects of biochar properties and nitrogen dosage on greenhouse gas emissions and yield of spring maize in the Hetao Irrigation District.
    Methods Both laboratory culture and field experiment was conducted in this research. The test materials were straw biochar and bamboo biochar. The field experiment treatments consisted of control (N) with a conventional nitrogen rate of 300 kg/hm2, straw biochar with a conventional nitrogen rate (SB+N), bamboo biochar with a conventional nitrogen rate (BB+N), straw biochar with nitrogen reduction of 50% (SB+50%N), and bamboo biochar with nitrogen reduction of 50% (BB+50%N). The static chamber-gas chromatography was used to measure the greenhouse gas emission in spring maize field. In the laboratory test, straw biochar (S) and bamboo biochar (B) with pyrolysis temperatures of 200℃, 400℃, and 600℃ were added to the soil. After three days of equilibrium, test soil under constant temperature and humidity was cultured for two weeks under 300 kg/hm2 N addition. N2O, CO2, and CH4 emission fluxes in soil were monitored in the different incubation days.
    Results Compared with N control, treatment SB+N, BB+N, SB+50%N and BB+50%N increased soil temperature in 0−5 cm depth by 0.50℃, 1.84℃, 0.35℃ and 1.37℃ respectively; increased soil temperature in 0−10 cm depth by 0.43℃, 1.83℃, 0.39℃ and 1.11℃, respectively; and increased the moisture content in 0−10 cm soil layer by 13.70%, 8.90%, 12.33%, and 8.90%, respectively. Compared with N control, cumulative N2O emission under SB+N, BB+N, SB+50%N, and BB+50%N decreased by 21.91%, 23.16%, 25.98%, and 28.17%, respectively, during the whole growth period (P<0.05). Cumulative CO2 emission under SB+N and BB+N increased by 7.96% and 9.94% (P<0.05), respectively, while that of SB+50%N and BB+50%N decreased by 11.54% and 10.74% (P<0.05), respectively. Cumulative CH4 emissions under biochar treatments during the growth period were negative and significantly lower than that under N treatment (P<0.05). The global warming potential (GWP) under SB+N, BB+N, SB+50%N, and BB+50%N decreased by 23.26%, 23.98%, 27.00%, and 29.14%, respectively, while the greenhouse gas intensity (GHGI) decreased by 27.24%, 28.97%, 32.57%, and 34.68%, respectively (P<0.05). Compared with N treatment, grain yield under SB+N, BB+N, SB+ 50%N, and BB+50%N increased by 5.47%, 7.01%, 8.26%, and 8.47%, respectively (P<0.05). Biochar addition reduced the emission of N2O and CO2 in soil in the laboratory test. The emission fluxes of N2O and CO2 decreased with increasing pyrolysis temperature of biochar. At the same pyrolysis temperature, the emission reduction effect of bamboo biochar was better than that of straw biochar. Soil CH4 emissions under all treatments presented carbon sinks, and bamboo biochar produced under 600°C had the highest CH4 absorption.
    Conclusions Biochar addition can improve soil temperature and moisture content, and significantly reduce the cumulative emission of N2O and CH4. However, biochar addition can increase the cumulative emission of CO2 under conventional nitrogen application. Biochar addition can significantly increase spring maize yield and decrease GWP and GHGI. The culture test further demonstrated that the emission reduction effect of bamboo biochar was better than that of straw biochar, and the emission reduction effect of biochar with high pyrolysis temperature was better than that of biochar with low pyrolysis. Considering the results of field experiment and laboratory test and environmental and economic benefits, the treatment of 50% nitrogen reduction combined with bamboo biochar was the suitable choice to increase maize yield and reduce greenhouse gas emissions in the Hetao Irrigation District.
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