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Effect of biochar amendment on yield and methane and nitrous oxide emissions from a rice paddy from Tai Lake plain, China

Zhang, Afeng, Cui, Liqiang, Pan, Gengxing, Li, Lianqing, Hussain, Qaiser, Zhang, Xuhui, Zheng, Jinwei, Crowley, David
Agriculture, ecosystems & environment 2010 v.139 no.4 pp. 469-475
Oryza sativa, biochar, emissions, fertilizer application, field experimentation, grain yield, greenhouse gases, growing season, lakes, methane, nitrogen fertilizers, nitrous oxide, rice, rice soils, China
A field trial was performed to investigate the effect of biochar at rates of 0, 10 and 40tha⁻¹ on rice yield and CH₄ and N₂O emissions with or without N fertilization in a rice paddy from Tai Lake plain, China. The paddy was cultivated with rice (Oryza sativa L., cv. Wuyunjing 7) under a conventional water regime. Soil emissions of CH₄ and N₂O were monitored with a closed chamber method throughout the whole rice growing season (WRGS) at 10 day intervals. Biochar amendments of 10tha⁻¹ and 40tha⁻¹ increased rice yields by 12% and 14% in unfertilized soils, and by 8.8% and 12.1% in soils with N fertilization, respectively. Total soil CH₄-C emissions were increased by 34% and 41% in soils amended with biochar at 40tha⁻¹ compared to the treatments without biochar and with or without N fertilization, respectively. However, total N₂O emissions were sharply decreased by 40–51% and by 21–28%, respectively in biochar amended soils with or without N fertilization. The emission factor (EF) was reduced from 0.0042kgN₂O-Nkg⁻¹ N fertilized with no biochar to 0.0013kgN₂O-Nkg⁻¹ N fertilized with biochar at 40tha⁻¹. The results show that biochar significantly increased rice yields and decreased N₂O emission, but increased total CH₄ emissions. Summary calculations based on this experiment data set provide a basis for estimating the potential reductions in GHG emissions that may be achieved by incorporating biochar into rice paddy soils in south-eastern China.